The ULTIMATE IGCSE Computer Science Paper 2 Revision

[Music]

Hi, I I go by Puppy in Discord and today we'll be going through the content of

IGCC computer science paper 2 as well as um attempting a paper 2 and um teaching you guys how I approached the 15 marker.

Uh last May June May June 2024 I have taken the exam and got top in country so you'll be in good hands and Ahmed will

be co-hosting the session. So say hi.

Hello everyone. I'm Ahmed. I'm CS helper in the in the server and I appeared for my CS exam last year in October November.

Yes. Okay, let's

start. So, yeah, covering chapters 7 to 10, solving paper two. Um, whatever

skill level you are, it will be suitable for you. It will be recorded and posted

for you. It will be recorded and posted on the channel that's linked in the chat right now. And uh there will be a Q&A

right now. And uh there will be a Q&A slide for after every chapter. So, you

so you guys can ask questions. However,

you can still ask questions and um Ahmed will be answering you or I will be depending on who's speaking. Yeah.

Yep. You can ask questions in chat as puppy goes along and I'll be answering them in chat.

So we'll start off with chapter 7 with the program development life cycle as well as you know inserting chapter 8 in

the design part because um pseudo code is in the design aspect and it's quite hard to introduce the whole chapter 7

without touching on pseudo code. So

yeah so first what is the program develop life cycle? So let's say you were trying to you know make a program.

These would be the four stages you will conduct um to successfully launch the program. First you analyze, then design,

program. First you analyze, then design, then code, then test. And also notice how it's a cycle. And that's because um for example if the program's hype starts

to die down it uh we might want to go through the cycle again analyze why um the hype is dying down and what are the

new requirements of the program. So

yeah, first in the analysis section there's abstraction. In

abstraction you would be simplifying the problem rem removing unnecessary details or essentially just you know removing parts

that the the client or whoever is giving you the task to do the program. you're

just removing the unnecessary parts. And decomposition is after you

parts. And decomposition is after you have abstracted the problem, um you'll break it down into smaller parts and chunking it so it's easier to

manage. And now for the design

manage. And now for the design section there is um the structure diagram, the flowcharts and the pseudo

code. So when you go about designing a

code. So when you go about designing a program you would be uh you can represent the the program in

these three types and so yeah so let's try a structure diagram. So in a structure diagram let's

diagram. So in a structure diagram let's let's try this exam question. So a

satellite navigation system is an example of a computer system that is made up of subsystems. This means that you know there's a top- down hierarchy

where there are subsystems down and down and part of the system has allowing the user to enter details or select a previously saved

destination. You could also display

destination. You could also display directions in the form of a visual map or list. And so now it's asking us to

or list. And so now it's asking us to draw a structure diagram to represent that.

My easy formula trademarked um is first we'll have the big system.

So we give the name of the overall system then the subsystem with input output processes or storage and try to apply

um those concepts into whatever the scenario is and then the further subsystems you name the action method.

So for this one, first you would name the quoteunquote big system as um the satellite navigation system.

Then there's the input part. So for the input part you would be um saying

input which could be new or it could be saved.

And um there is also the output which could be a visual map or a

list and you know just so everything is clear I have the answer on the next slide.

One second here. But don't worry about um you know

here. But don't worry about um you know not matching the mock scheme exactly because the mock scheme is quite lenient. Here is the actual mock scheme

lenient. Here is the actual mock scheme and they just ask one mark for hierarchical structure, one mark for suitable names for subsystems, one mark

for identifiable inputs and one mark for identifiable outputs. So as long as you

identifiable outputs. So as long as you know um you're answering structurally just like this then it'll be

fine. Next we have

fine. Next we have flowcharts. So, a flowchart, as you guys

flowcharts. So, a flowchart, as you guys know, um is a series of flowchart symbols connected by a flow line here, um forming a step-by-step idea of the

algorithm.

So, I'll just show you guys an example and uh we'll refer back to what each symbol means. First, the start. So, yeah, we're

means. First, the start. So, yeah, we're just starting the program here.

Then we print out we print out the menu like this program would be uh a cashier system. We print out the menu. Then we

system. We print out the menu. Then we

initialize the total um total price of the bill. Then we output asking for how

the bill. Then we output asking for how much the item price is. Input the price.

Total it up. And um if the user wants to end it just there, they would enter minus one. it would go back. No, and it

minus one. it would go back. No, and it would just output and stop. Else it

would go back and ask for the next item. And notice how I total equals

item. And notice how I total equals minus uh equals 1 instead of zero. And

that is because minus one um the last item would be minus one and that would cancel out with the one that it started

with. Now what each of them mean?

with. Now what each of them mean?

So first this one is a sub routine. So it it will run a separate

routine. So it it will run a separate and non-length flowchart that is um in another place. Then this is called a process

place. Then this is called a process box. So you might assign variables, you

box. So you might assign variables, you might calculate, you might um yeah and parallelograms are called input or output boxes. So you'll be

outputting a phrase or inputting um for an identifier. Then that is another process

identifier. Then that is another process box that is called a decision box. And

instead of an if you'll be an is and uh there would be yes or no. So

yeah and then a stop. Those are called terminators start and stops. Okay. Um that would be the

stops. Okay. Um that would be the program development life cycles analysis and design section and in the design section there's pseudo code. So Amid

will be teaching you guys the pseudo code syntax.

Okay. So now we're going to start with chapter 8 in which we're going to first cover pseudo code basics syntax variables and arrays. Then input outputs library routines operators and

selection. After that, we are going to

selection. After that, we are going to have a question and answer session. Then

we're going to go to file handling uh iteration and sub routines. Okay, let's

routines. Okay, let's go. Okay, so when we're using pseudo

go. Okay, so when we're using pseudo code to construct a solution to a problem, we need to follow a certain set of rules. Okay, before I carry on, am I

of rules. Okay, before I carry on, am I audible to everyone? If I'm not, you can right

everyone? If I'm not, you can right click on my user and increase user volume.

Okay, perfect. Okay, so you are supposed to follow a certain set of rules. Now,

these rules are called your syntax. Now,

some very basic rules would include that your keywords such as outward, close file, read, uh, repeat, they always need to be in uppercase. Secondly, your

identifiers, they need to be in Pascal case. For example,

case. For example, uh, team names and student marks. Now

you can never put a space between those two and you can never use an underscore in your identifiers. Okay, moving on. When now

identifiers. Okay, moving on. When now

we're going to talk about indentation.

Now when a new line is being made within a statement, we indent the new line by four spaces. Indent means that we're

four spaces. Indent means that we're going to leave four blank spaces from the left and then continue with our statement. When assigning when assigning

statement. When assigning when assigning to variables in pseudo code, we use the arrow key in which we use the we use the

arrow key and we ident we put the name of the identifier, the arrow key and then the value we are assigning. The

value could be another variable, the value could be uh the value could be an expression, anything. We have a small

expression, anything. We have a small example of pseudo port towards the left of the slide towards the right side of the slide. And here you can see an

the slide. And here you can see an example of indentation where when we make uh when we when we make a statement inside of the for loop we leave four

spaces. Okay, that's it for basic

spaces. Okay, that's it for basic syntax. Let's move

syntax. Let's move on. Now we're going to start with

on. Now we're going to start with comments. Comments are added to make our

comments. Comments are added to make our program more readable and maintainable.

So for example uh this is a program that swaps the values of two variables x and y. Now

to a new programmer who has not written this code this might be confusing. So we

can add comments preceded by double slashes and a space. And then we write and now these comments they are ignored by the compiler. So they aren't part of

your code. They're basically added as an

your code. They're basically added as an aid to you in the future or some other programmer to understand the function of your code or understand the function of specific parts of your code. That's it

for comments. Let's move

on. Okay. Now we have data types.

Firstly, data types we have in identifiers we always use Pascal case.

Let's remember that. And we can only use letters and digits when uh defining our data types. Okay, so A to Z and 0 to 9.

data types. Okay, so A to Z and 0 to 9.

And keywords such as input and output should never be used as your identifiers. Now integer is our first

identifiers. Now integer is our first data type. An integer is basically a

data type. An integer is basically a whole number. It could be five, it could

whole number. It could be five, it could be minus3, it could be minus 10. A real

is a decimal number. So in a decimal number, you can you need to have a number on either side of the decimal place for it to qualify as a real number. for pseudo code. Uh a char is a

number. for pseudo code. Uh a char is a single character. Okay. And it is

single character. Okay. And it is enclosed in single quotation marks unlike a string. A string is a sequence of zero or more characters and is

enclosed in double quotation marks. Now

what's important is that a string can also have zero characters. So this is important when we're doing things like presence checks. So a string can have

presence checks. So a string can have zero characters as well. Lastly, we have booleans. So the booleans are basically

booleans. So the booleans are basically variables that store the logical state of true or false. Okay, let's move

false. Okay, let's move on. Next slide. Okay, declaring

on. Next slide. Okay, declaring

variables and constant. Firstly, a

variable is a variable can store many values. A variable can have a new value

values. A variable can have a new value written to it in the middle of your code. You declare a variable as follows.

code. You declare a variable as follows.

Firstly, you use the declare keyword.

You use the declare keyword again in capitals followed by the identifier and then the data type in capital. For example, declare counter as

capital. For example, declare counter as an integer or declare flag as a boolean.

Now this is different when we work with constants. With constants we don't

constants. With constants we don't mention the data type. We only mention the literal. The literal are the values

the literal. The literal are the values that a data type can store. For example,

constant pi we use the assignment arrow 3.14.

Okay so 3.14 is going to be stored to pi. For

constants, you can in pseudo code, you can never assign another variable to a constant. You can never assign uh uh

constant. You can never assign uh uh another constant to a constant or an expression. You must always uh assign a

expression. You must always uh assign a literal to a constant. And a constant should always be assigned at the start of your code. This isn't necessary, but it's good practice because your constant

cannot be changed once it's assigned.

Moving on.

Okay. 1D arrays. An array is essentially a data structure that can that contains several elements of the same data type.

So an array can only store one type, one data type. So you declare an array as

data type. So you declare an array as follows. The declare keyword. Then

follows. The declare keyword. Then

moving on. Okay. Uh in chat guys, ping puppy if you have any questions. Okay.

he'll be answering your questions in chat. Okay. Declare you put in the

chat. Okay. Declare you put in the identifier of the uh array you want to use and then you put in the lower bound and then the upper bound. Now it's

important that your upper lower bound should always be smaller than the upper bound and your lower bound is the first index of your array and your upper bound

is always the last index of your array.

So the index of your array is essentially the row. For example, uh the fourth index in the array you see on screen would be Sarah. So if we were to

use this and for example, if we were to output names index 4, we would do this by enclosing four in square brackets, it would output the string Sarah.

Okay, let's move on. That's it for this slide.

Okay, for assigning content to an array, we can also you we use the assignment arrow. For example, names five and we

arrow. For example, names five and we use the assignment arrow of David, it would assign the value, it would assign the string David to the fifth index.

Now, you can see in the array it says Jonathan on the fifth index. Once we

assign it David, Jonathan is overwritten and now the fifth index will be David.

Okay, let's go.

2D arrays. 2D arrays are like 1D arrays but they are like a table because they don't just have rows they have columns as well. So we declare them similarly to

as well. So we declare them similarly to a single to 1D arrays but after that we after adding the number of rows we also add the lower bound of columns and then

the upper bound of columns. Okay, if you don't understand rows and columns rows are the these these are your rows.

Okay, these are your rows and these are your columns. Okay, so as you can see as

your columns. Okay, so as you can see as in the when we declare, we declare student marks as array 1 to 3, 1 to two.

When we're declaring, we always declare the rows first. Okay, you can if you keep forgetting which one is which one comes first, remember it as remote control, rows, columns, remote control.

Okay. So the rows are declared first.

These as puppy mark these are your rows and then the columns columns 1 2. Okay.

So these are your columns. Now when we use 2D arrays we

columns. Now when we use 2D arrays we again once again we do rows first and then we do columns. For example, if you were to do output student marks square

brackets 2, 1, we would get the marks of student B in history, which would be 22, right? So, I hope that makes sense.

right? So, I hope that makes sense.

Okay moving on. Chapter 8. Okay, that concludes

on. Chapter 8. Okay, that concludes syntax, variables, and arrays. We're now

going to be moving to input, outputs, and library routines. Let's go.

Okay, first we input an output. This is

pretty this is pretty simple. Okay, when

if you want to input a value into an identifier, if you want to prompt the user to input a value, we use the input keyword followed by the identifier that we are writing to. Now what this would do it was it would prompt the user to

enter a value and then that value would be written to the identifier. In

outputting, we use the output keyword and then we would put in the expression that we want to be output. For example,

if you look to the bottom of the slide, we prompt a user to enter your name and then it inputs the name into student name. And

name. And uh you might be confused about what expression means in output. Okay. So

over here you can see in the last line output student name student name is going to be output the value inside of student name. Let's say the value is

student name. Let's say the value is John. The string inside student name is

John. The string inside student name is John. got core we the score of that

John. got core we the score of that student is 22 and then we have the string marks. So now once we run this

string marks. So now once we run this this would translate to John got 22 marks. I hope that makes sense. Okay

marks. I hope that makes sense. Okay

let's move on. Now we have arithmetic operators. We have the very simple ones

operators. We have the very simple ones addition subtraction multiplication division and raising to the power of.

These are very simple but what most people get confused about is integer division and modulus. Firstly, what

integer division does is it returns the quotient of a division of a division operation with the remainder discarded.

For example, 10 / 3 it leaves us a quotient of three with a remainder of 1.

So div d 10 3 gives us the value of three. It gives us the quotient and

three. It gives us the quotient and discards the remainder. Now modul what modulus does is it finds the remainder of a division operation and then

discards the quotient. So for example 10 / 3 leaves us a quotient of three and a remainder of 1. Now mod 10 3 would give

us a value of 1 as the remainder of the mathematical operation is one. Okay, I

hope that makes sense. Now we're moving on to logical

sense. Now we're moving on to logical and boolean operators. Logical operators

are pretty straightforward. Equal to,

less than, less than or equal to, greater than, greater than or equal to, and not equal to. Now an examples towards the right. If value 1 equals to

value two, then we are going to output the statement values are the same and if. Now for those of you who don't know

if. Now for those of you who don't know for loops at the moment, what basically this will do is it will check to see if value 1 equals to value 2 and it will

output the values are the same. If it

is, it's pretty simple. Now in the second example, if value 3 is greater than value four, then it will output value 3 is greater than value four.

Pretty straightforward. If it's not greater than value four, it will not output that statement. Now uh logical the result of a logical operator is

always uh a boolean state. For

example, the we have the last example is different. Now value if value five and

different. Now value if value five and value six are not equal to each other this will translate to true. If value

five and value six are different uh this will translate to true and the boolean state true will be stored in the is different variable.

Okay, moving on to boolean operators. The boolean operators are

operators. The boolean operators are boolean operators puppy. Okay, and or and not. Now moving towards the right in

and not. Now moving towards the right in the example. If answer is smaller than

the example. If answer is smaller than or equal to zero and answer is greater than or equal to zero then output value

is in range otherwise else output value is out of range. So what essentially this does is it's the same as the value above, but what it will do is it'll

check to see if both these expressions are true. Both of these expressions need

are true. Both of these expressions need to be true in order for the then statement to be executed. If one of them is true and then the other is false, the value will still not be executed as it

requires both conditions to be true.

Moving on, let's go to the next slide.

Now we have library routines. Uh firstly

we're going to start with string operators. We have four string operators

operators. We have four string operators length, lc case, ukase and substring. So

what length what length does is it takes the length it returns the length of a string. For example, if we input the

string. For example, if we input the string happy days, it will return the value 10. It will return the integer

value 10. It will return the integer value 10. This is because there are 10

value 10. This is because there are 10 characters in the length in the length string. Okay? And this always includes

string. Okay? And this always includes the space. You always need to count the

the space. You always need to count the space as a character also. Now the LK case what the

character also. Now the LK case what the LKS function does is the LKS functions returns the LK case function returns a string in lower case as seen in the

example. The UK function returns a

example. The UK function returns a string in uppercase. All the characters will be uppercase. Okay. Now substring

what's substring? Substring is a little confusing. What substring does is it

confusing. What substring does is it returns the part of the string starting from the it returns a part of the string starting from the start character that

we give it and it will be of the length we give. For example, if we give it the

we give. For example, if we give it the string happy days and we're starting at uh the second character we're going starting at a and the length of the and

the length of the output string is to be four. We're

going to count four letters A, B, P, Y.

So substrings substring happy days 2 4 will return with the string happy. Make

happy. Make sense? Okay, let's move on to the next

sense? Okay, let's move on to the next slide. Now we have round and random

slide. Now we have round and random which are the last operators. Okay, random returns a real

operators. Okay, random returns a real number from 0 to one inclusive.

So if you move on to examples, you'll see that random running random would return a value like 0.5 53575 46 whatever. Okay, a very large decimal number. Now in most use cases

decimal number. Now in most use cases this would be pretty useless as it returns a random decimal number between 0 and 1. That's why if we wanted to say

make an output a number between 0 and 5, we would do random* 5. Now what's

important to note here is that this would output a number between 0 and five not 1 and five. If you do randoms times 5, it will never output a number between

1 and 5. It will output a number between 0 and five. Okay? So that's something that most students confuse. Again, a

decimal number of that size will be essentially useless to most of your cases. So that's when the round function

cases. So that's when the round function comes in. Now standalone what the round

comes in. Now standalone what the round function does is that it returns the value of a variable rounded to the amount of decimal places that you specify. For example, rounding

specify. For example, rounding 3.1415 to one decimal place would return with the would return with 3.1. Okay. So

simple enough. So how are we going to use round and random together to return a whole number between say 0 and six?

Round. Firstly we're going to use the round function. Then in the brackets

round function. Then in the brackets we're going to put random * 6 to zero places. Now what random* 6 is going to

places. Now what random* 6 is going to do is it's going to make random decimal number between 0.0 and 6. So that's the

random part covered. Now this random value will exist inside of the round inside of the round function. So the

round function will round it off to zero decimal places. So if the value is

decimal places. So if the value is 4.23517 2 3 5 1 73 it will round the value off to four and the final result we get will be four. Make sense? Let's

move on. Okay. Selection. Now we're moving on

on. Okay. Selection. Now we're moving on to selection. If statements basically

to selection. If statements basically now with selection we have two types of selection in pseudo code. If statements

and case of statements. We're going to start with if statements. Firstly, if

statements only run if a condition is true. We provide if statements with a

true. We provide if statements with a certain condition. The program checks to

certain condition. The program checks to see if that condition is fulfilled and then it executes the statements we give it. Now, an if statement can be written

it. Now, an if statement can be written either with or without an else statement. In the first example, we do

statement. In the first example, we do it without an else statement. If student

marks is greater than 40, then output pass. Okay? So if student marks will be

pass. Okay? So if student marks will be greater than 50 it will output pass and if you always end if okay when you write with an else statement your else

statement you write if a condition is fulfilled then output a certain statement if this condition is not fulfilled the statements written under the else statement will be under the

else clause will be executed. So if

student marks is greater than 40 then out would pass else output fail. So if

the student marks is 23 for example, it would output fail and then we close it off with end if. Now then let's go on to the next slide. We're going to do nested

ifs next. Okay, nested ifs are if

ifs next. Okay, nested ifs are if statements inside of an if statements and this has many use cases. In IGCSC

pseudo code, you will only be required to write up to three levels of nested if statements. Now if we move to the

statements. Now if we move to the example here, puppy, if you can bring the pointer. Now we have the first if

the pointer. Now we have the first if statement in black. If student marks is greater than 40 then execute. Now within

the then clause within the then statements of the first if statement we've started another if statement. So

if student marks is greater than 40 then then this if statement will be executed.

Then if student marks is greater than or equal to 70 then output distinction otherwise else output pass.

Okay. So if student marks are greater than 40 the second if statement will come into play. And if the student marks are greater than 70 it will output distinction. If it's something like 50

distinction. If it's something like 50 it will out pass. Now and then end if the first if statement closes. The first

if statement is in the golden color.

Okay. and then it will output good job.

It's important to note that the good output good job statement is within the first if statement. Okay, the second if statement has ended. It is within the then statements of the first if

statement. And we then go on to the else

statement. And we then go on to the else clause of the first output statement and it will then output if student marks is

not greater than or equal to 40 it will output fail. Make sense? and then end.

output fail. Make sense? and then end.

And that's nested of statements. Okay. Case of statements.

statements. Okay. Case of statements.

Case of statements allow different statements of code. They allow one of several branches of code to be executed depending on the value of a variable.

Okay. Case of statements can be written with an otherwise clause and without an otherwise clause. This is shown in the

otherwise clause. This is shown in the examples here. First, we're going to do

examples here. First, we're going to do it without an otherwise clause. Let's

bring up the example. Okay. Example. Okay. So, this

example. Okay. Example. Okay. So, this

is a program that takes in a number as an input and then displays a message.

So, what a case statement does is that it checks to see if a case applies. For

example, when a case is applied, it the statements in front of that case are executed. So input number, we in take an

executed. So input number, we in take an input of a number and begin case of that number. Now if that number is one, the

number. Now if that number is one, the output will be lucky number one. If it's

two, the output will be cool number two.

If it's three, awesome number three, four, great number four. Now if none of these values if the num if the variable number does not store 1 2 3 or four and

another value it will output your number is invalid. So the otherwise the

is invalid. So the otherwise the statements of the otherwise clause are executed when none of the cases above it are applied and then you end the case of

statement with end case. That's it for case statements. I think we begin the

statements. I think we begin the question answer session after this. Yep.

Okay. Now we have concluded input output basic library routines operators and selection.

Okay. Um Okay.

I want to talk. I want to talk. I I feel I feel extroverted now not having to talk for so long. Does the condition have to be a number um in a case or can

it be boolean like a string?

Sorry, can you repeat it? I do not know what they meant. Does the condition have to be a number in a case or can it be

like a boolean or a string? In the case of statements, if that's what you're talking about, um the the variable can

be a string. Yeah. Yeah. It can be of any data type, right? Yeah. So it can be like case off name and then it would start with I don't know John, David,

Sarah. Then I'll put different greetings

Sarah. Then I'll put different greetings for them for example. Yep. Cuz the syllabus doesn't

example. Yep. Cuz the syllabus doesn't specify that case of only applies to integers. Okay. So it can be booleans,

integers. Okay. So it can be booleans, it can be strings, it can be chars in a substring. Yeah. So it's the

variable you're referencing, then the start index, then the length.

Yep.

Any other questions?

Any other questions, guys? That is allowed

guys? That is allowed um any single statement. So, you can do one one statement, but if you do multiple, you can't. So if you want to

put multiple statement um in the case of something then you would be using a procedure or a function instead

which you'll learn in a bit. Uh yeah and the syllabus specifies that you should only keep your case of statements to one line. If they exceed one line you should

line. If they exceed one line you should use if statements instead of that. So

you can go on to use nested ifs for that. Okay. Someone asked about

that. Okay. Someone asked about substring. So

substring. So um the start index is where where the part of the string you're trying to

extract starts. For this instance you're

extract starts. For this instance you're trying to get app and it starts with a.

A is the second um index second position. So that's the start index of

position. So that's the start index of two and the length is four. So it

becomes happy. Um I've heard what do you mean by indenting? So indenting

basically uh means you know um writing the code like putting a space before or a tab before writing the code or here

for example you're putting space before because it's in the case off section.

That's what indenting means.

Can you show the nested diffs again? Got

a look at it.

Someone wants to see the neester diffs again. Nester diffs. Okay. How do you

again. Nester diffs. Okay. How do you know when to indent? So if you're um if you're using some like fancy

control structures like if or case or in the future we're about to teach like for loops or while loops anything that

um is a fancy control structure then you indent inside. Will you lose marks? Um,

indent inside. Will you lose marks? Um,

in normal questions, I believe you don't. But regardless, you should just,

don't. But regardless, you should just, especially in the 15 markers, so the the examiner has an easier time marking for

you, even if it Yeah, actually. Yeah,

readability is one part of um the 15 marker.

Syntax definitely carries mocks. It's

specified in the marking scheme for it.

Any other questions? Okay. And uh there was a the for the uh what was it?

Indentation question. Uh when you're making well the what the syllabus wants you to do is when you're making a statement inside of a statement you

indent it by four spaces. Okay. And for

example, if you're using an if statement. And now the syllabus says

statement. And now the syllabus says that when you're using an if statement, you don't need to indent four spaces for the then clause. when you add the then clause, you indent two spaces because

the then clause is essentially an extension of the if statement. Uh the

same goes for when you're using nested ifs. If you're putting an if statement

ifs. If you're putting an if statement inside an if statement, you only leave two spaces, not four. But for example, if you have uh an if statement uh and

you're if and then and you're adding an output statement, if you're putting an output in there, then you need to indent the thing by four spaces. If say you're

using a case and and case of and then you're inputting the values, you leave a space of two, not four. Okay? Because

they are an extension of the initial statement. That's what the syllabus

statement. That's what the syllabus says.

Okay, puppy. Any other questions?

I have not seen.

Will we lose Mark if we use case?

No, it's a feature. You should use it.

Uh, and no, you don't have to number your lines. You once you get the exam

your lines. You once you get the exam paper, you're not supposed to number the lines. You're supposed to indent. You're

lines. You're supposed to indent. You're

supposed to comment.

It's just easier to write here. Uh, no,

show you guys like this.

Okay, puppy, there's a question and this is I think an important one. Can we

write the if statement like this? If

variable statement two space then essentially can I put the then clause right after in the same line as the if statement. I've seen this a lot in the

statement. I've seen this a lot in the channel as well. Yes, you can.

I prefer that actually. Yeah. Um, oh

yeah, cuz most of the languages do it that way, right? The Yeah, language. And

also, and one more thing question, sorry, continue. You don't have to

sorry, continue. You don't have to bother with the two space indentation or whatever with um with the then.

Yeah. And

uh Okay. Is there a terminating command term like end or do we have to use an explicit variable such as a found to terminate

the repeat until? You will have to use a variable. There is no break. There is no

variable. There is no break. There is no nothing to end it.

Yeah. Um what if there is no space for you to write the statement in one line?

So, uh, you just carry on the well, try to squeeze it if you can, but if not, carry on on the next line. And if it's an indented statement, then don't indent

the next line. You're carrying on because you're showing you're carrying on. You're not showing that you're

on. You're not showing that you're writing another statement. Do you comment with a slash

statement. Do you comment with a slash or hash slash?

[Music] Um, we will do passages at the end.

pseudo code you're supposed to use / slash. Okay, for if statements the

slash. Okay, for if statements the question that we get often is can you can we use else if in pseudo code? It

would be best if you don't use L-s because the because Cambridge has specified a certain syntax for pseudo code and since pseudo code carries marks and since syntax sorry since syntax

carries marks you should always use nested if statements instead of else if okay techni okay so why can't you so it's just it doesn't exist on the

syllabus and if you do um what you do is you put an a space between else and if and you add an extra end if at the end.

So, it's no different from just, you know, using an uh if or else.

Okay, I think that's it for now. Emit

continue. I'll answer in chat. Okay, so

now we're now going to start with iteration. Firstly, we're going to start

iteration. Firstly, we're going to start count controlled for loops. So, for

loops are four loops iterate a set number of times. Iteration basically

iterate means loop for loops loop a set number of time. Now for loops take an identifier of data type integer. So a

variable the variable that we use in this for example in our example we have for counter 1 to 10 output counter and the next counter. So in this example,

the variable counter will be assigned each integer value from 1 to 10 from value 1 to value 2. In our case, this is going to be each integer value from 1 to

10 until it reaches the value 10. So it

is going to increment every time.

Increment means increase.

Okay? So it's going to begin with one for counter 1 to 10. Output counter is going to output one. That's one

iteration complete. On the next iteration, it's going to be incremented.

It's going to be increased to two. It's

going then it's going to go ahead and output two. We're going to show a

output two. We're going to show a demonstration for this on pseudo code pro in a bit. Okay. So, basically now by

default in four loops the the variable is incremented by one. So 1 2 3 4. We

can use the step clause to set the increment. So if we use a step of two

increment. So if we use a step of two then we can increment the variable by two on every iteration. So one then three then five. We're going to demonstrate that on pseudo code pro in

just a second. Let's move on to the next example. For example, if we have a step

example. For example, if we have a step here four counter 1 to 100. Oh counter 1 to 100 step two. So

100. Oh counter 1 to 100 step two. So

this is going to go one then three then five. and it's going to output counter

five. and it's going to output counter at every iteration and after every iteration it's going to increment it by two. Now step clauses can also be

two. Now step clauses can also be negative. Now when step we use a

negative. Now when step we use a negative step clause then what we do is we make value one larger than value two.

So we iterate from a larger value to a lower value. Puppy can you pull up the

lower value. Puppy can you pull up the example for negative? Okay. So here you can see that

negative? Okay. So here you can see that in the first two examples our value one is smaller than our value two because we're incrementing we are increasing until we reach the value two which is

higher than the first value. When we add a negative increment a decrement essentially. So we have uh our value one

essentially. So we have uh our value one is greater than our value two because we're because we're decreasing the

identifier from value one to value two.

Okay, let's go to the demonstration and then it'll make more sense. Okay, first we're going to go

sense. Okay, first we're going to go without a step first. Declare counter.

Now when we run this after every iteration counter is going to be incremented by one and it's going to output numbers from 1 to 10. Okay. Now

what we're going to set a step of one puppy. So by default

puppy. So by default uh the step of a for loop is one. So if

we set the step to one you'll see that there is no change in the output.

However, if we change the step to two, let's change the step to two. Okay. So now it's going to

two. Okay. So now it's going to increment counter by two on every iteration. So it's going to output one.

iteration. So it's going to output one.

Then it's 1 + 2 3 3 + 2 5 5 + 2 7 and then 9. But when it reaches nine, okay,

then 9. But when it reaches nine, okay, what's very important is that if an iteration causes the value of

the identifier to cross the second value, the loop will terminate. Now this

might not make sense. I'll repeat. If an

iteration causes the value of identifier to pass value to the loop terminates.

You can see this as we have nine. Right?

Now the code would have iterated and when the code iterates with a step of 2, 9 + 2 would have been 11. This would

have given you 11. But our upper bound in this is 10 is the higher value which is value two. It's not it's higher. It's

sorry it's lower than 11. It's 10. So it

can't cross in. Hence that iteration never takes place and that increment never takes place. I hope that makes sense. Okay. Now let's move

sense. Okay. Now let's move to the next slide. Yeah, that's it for for loops.

slide. Yeah, that's it for for loops.

Okay, now we have postcond conditional repeat and preconditional while loops. So the repeat loop uh what repeat

loops. So the repeat loop uh what repeat loop does is that repeat the conditions inside a repeat loop will be executed at least once. So repeat loop check the

least once. So repeat loop check the repeat loop contains a condition at the end. After every iteration of the repeat

end. After every iteration of the repeat loop, the repeat loop checks to see if a certain condition is fulfilled. Now if

that condition is fulfilled, the repeat loop will terminate. However, if it's not fulfilled, if the condition evaluates to the boolean value of false,

it will keep iterating until it evaluates to the boolean value of true.

Okay. So what we're going to do is see an example. Now this starts a repeat

an example. Now this starts a repeat loop. Repeat loop starts output enter

loop. Repeat loop starts output enter the password and it will prompt a user to enter the password. Now the password will be one. Now the password in our

case is 1 2 3 4 5. Now until the user enter password equals to 1 2 3 4 5 the repeat loop will keep looping.

Okay. Now I hope that makes sense. Going

over to while loops now the while loop is a preconditional loop. The condition

in a while loop is tested before the statements are executed. And the

statements will only be executed if the condition evaluates to true. Okay. For

example, while condition while condition is true do statements. So the statements are only going to execute when the when

the condition evaluates to the boolean value of true.

Um okay. So the loop we the loop might never iterate. So if we start the loop

never iterate. So if we start the loop if the control is given to the while loop and the condition is not evaluated to false to true and it's false. This

loop will never be executed. At every

iteration after the statements are output. What the loop does is it checks

output. What the loop does is it checks to see if the value if the value is remains true. The second the value

remains true. The second the value becomes false this it terminates. Now in

the example here we have output enter the password. It prompts a user to enter

the password. It prompts a user to enter the password. So while password does not

the password. So while password does not equal to 1 2 3 4 5 output incorrect password and in and prompt the user to enter the password again. So, it's going

to input, it's going to prompt the user to input the password again and again and again until it's 1 2 3 4 5. Okay, let's move on to the next

5. Okay, let's move on to the next slide. Now, we're going to start with

slide. Now, we're going to start with sub routines. Firstly, we're going to do

sub routines. Firstly, we're going to do procedures, then we're going to move on to functions. So essentially a procedure

to functions. So essentially a procedure is a set of programming statements that are grouped together that can be called to perform a certain task at any point in the program. Okay, please go slow

here. Okay, I'll explain this in detail

here. Okay, I'll explain this in detail since a lot of people don't understand that. So we use sub routines when our

that. So we use sub routines when our program has certain tasks that are repetitive. So if for example our

repetitive. So if for example our program needs to print and for example our pro procedure needs to output the

menu again and again and again instead of typing out the meat beef pork vegetables carrot lettuce again and again and again. We can

just define the procedure the sub routine at the start of the code and then we can call it anytime inside of

the code. So what it essentially does is

the code. So what it essentially does is that it allows us to do repetitive to call repetitive tasks easily. Then now

this is how you define a procedure. You

use a procedure command. You give the procedure a certain identifier and then you input the statements that are going to be executed once the procedure is called. If you don't understand what

called. If you don't understand what being called means, we're going to explain that in one second. Okay. So

look at the example here. The procedure

is the identifier of the procedure here is print menu. And what this does is it outputs two output statements containing foods. Okay. And then we end procedure.

foods. Okay. And then we end procedure.

Okay. So when we call a procedure, we use the call keyword. Okay. Call

followed by the identifier. So here we output the string hello customer please look at our menu. And then we say call print menu. So this is going to output

print menu. So this is going to output the string hello customer please look at our menu. Then it's going to call the

our menu. Then it's going to call the print menu procedure and then the statements within that procedure are going to be executed sequentially. First

it it's going to output meat, beef and pork and then it's going to output vegetables, carrot and lettuce. Okay. So

this is how we this is how we uh use procedures without parameters.

Procedures can also be used with different parameters. One second. the

different parameters. One second. the

parameters entered in a um just to emphasize on the use case of procedures, right? Uh so for example, the customer

right? Uh so for example, the customer maybe you run into a new customer. So

you would use you would call print menu again. So you can print the menu again

again. So you can print the menu again or if the customer wants to reorder again um you can call print menu.

Yep.

So basically we streamline tasks that would have been repetitive. Excuse me

just one second. Apologies. Okay, I'm back. Okay,

second. Apologies. Okay, I'm back. Okay,

so this was an example of using procedures without parameters. We can

also use procedures with parameters.

Okay, let's move on. That's done.

Next, you can also give your parameters.

Now, we can use now we've seen one use case of this. Okay, now we're going to see a procedure with parameters.

Parameters, the parameters that we enter into a procedures will be used as variables in the statements of the procedure. For example, this is how you

procedure. For example, this is how you declare a procedure with parameters.

Firstly the procedure followed by its identifier then brackets then the uh identifier of the parameter and then the data type. Okay. So for example

data type. Okay. So for example procedure greeting first name is going to be string and the last name being input is also going to be string. It's

going to output once the procedure takes in these parameters it's going to use these parameters in its statements. So

it's going to output good morning mister and then it's going to output his last name. You can see the last name is the

name. You can see the last name is the same identifier as the parameter that we've entered. So and then we're going

we've entered. So and then we're going to go output could I call you first name. Same once again you'll see is

name. Same once again you'll see is going to be the same identifier as the as the uh parameter that we used for the first name. And then we do end

first name. And then we do end procedure. Calling a procedure with

procedure. Calling a procedure with parameters is is almost the same. You

use the call keyword and then you put the identifier. In this case, we

the identifier. In this case, we declared it as greeting and John Smith.

Okay? So, a string containing John, Smith. So, when this is called, it would

Smith. So, when this is called, it would output good morning Mr. Smith. Could I

call you John? That's

John? That's it. That's how you streamline repetitive

it. That's how you streamline repetitive tasks. Okay, moving on to functions.

tasks. Okay, moving on to functions.

Functions are just like procedures. They

function the same as procedures except they return a value to the main program to the point at which to the point at which they were called. Okay. So for

example, uh we define a function with parameters such as function identifier the data type one. So the we declare the first

one. So the we declare the first parameter with its data type and then the second with this data type. When

defining a function, we also use the returns keyword which tells us which data type is going to be returned to the point that it was called. Okay. So this

is how a function works. We have the GIF. Puppy, if you could pull up the

GIF. Puppy, if you could pull up the pointer. Okay. So we declare result as

pointer. Okay. So we declare result as an integer and then we start a function add two. We call the function add two.

add two. We call the function add two.

Now what this function essentially does is it takes an input of an integer and then it uses and then it adds two to that integer. So we are specifying that

that integer. So we are specifying that this function will return an integer value.

So we take the we take the result variable and we assign it the okay let's wait for the gif to loop back okay so

we'll start we call it with the value seven we add two to seven and store that value in result and then return result

we return 9 the output is 9 okay I hope that makes sense to [Music] everyone Let's wait for the GIF to loop

back and I'll explain this one more time just if somebody has understood. Okay,

so we add the number seven as a parameter. It adds two to the number

parameter. It adds two to the number seven. It stores it in the value result.

seven. It stores it in the value result.

It returns result which is 9 and it outputs 9. See to the point where the

outputs 9. See to the point where the function is called. Hope that makes sense. Let's

called. Hope that makes sense. Let's

move on. I think that's oh file handling remains on okay let's move on now moving on to file

handling so file handling uh so for file handling we have reading to and writing to a file so before reading to or writing reading from or

writing to a file we must open a file first this is done using the open file command in capital again with the file identifier so now we have two modes for file

one is for the first is the read and then the second is the right mode. Okay, sorry. Uh so we can either

mode. Okay, sorry. Uh so we can either have it for read or we can have it for write. So once we open a file, let's

write. So once we open a file, let's move on to the example here. Okay, so

this example what this does is it copies uh a string from file A and then it stores that string in file B. First we

declare data as a string. We open the file file a.txt for read. Okay, this is important. Notice how it says read. Then

important. Notice how it says read. Then

what we're going to do is we're going to read file file a.txt, data. So what this is going to do is it's going to read the contents of file A and it's going to

store its contents into the variable data. Okay. And then we're going to

data. Okay. And then we're going to close file A.XT using the close file command. So now the contents of file A

command. So now the contents of file A are stored in the variable data. Now to

write it to file B, we're going to open file B dot txt. Open file for write write mode. Okay. And then we're going

write mode. Okay. And then we're going to use we're going to use the write file command for file B txt. Write file.

Fileb.txt data. That means the contents of the variable data are now going to be written to file B. And then we're going to close file B. So now we have copied

the data from file A over to file B. Okay, that's it.

B. Okay, that's it.

That's my part done. We're done with chapter 8, pseudo code.

Um, so first, uh, why would you use parameters instead of just directly hard coding it in?

So for example in the greeting you might want to greet two different persons. So

you might want to call greeting once on John Smith and then call greeting David Blaine. So then now it will it will be

Blaine. So then now it will it will be good morning Mr. Blaine. Can could I call you David? So

um you know it's uh the the procedure is flexible to whatever you input in and I've seen another question

[Music] somewhere local variables can't be changed outside of the function right yes

um so the there is this concept of local and global variables so if If you um declare or assign a value normally

then then it it can be used throughout the program if it's in the main program.

But if you assign a value within the function then the value can't be used outside in the main program. For

example, um this result here, the result variable, it has became nine. But that

nine that result um variable if like you can't reference it. You can't do output result below here. It it just won't understand um what result is because

result only got assigned within the function. It's a local variable rather

function. It's a local variable rather than global.

Do we understand? Return and call. Yeah,

understand? Return and call. Yeah,

there's specific to each type. So in in procedures you're you're calling because you're not returning to a function. So

you're just calling the set of instructions inside. Whereas in

instructions inside. Whereas in functions um now you actually have to use it use the value. So you either output the

the value. So you either output the value you assign the value somewhere or do something with the value.

So now for example you could also say um like

answer is add two of seven. So now this answer can actually

seven. So now this answer can actually be reused somewhere rather than output

result that does not work because the result got assigned within the function.

So it didn't get return. Well, it got returned out to the output statement, but the variable result itself is still in um the function. So you can't do output

result because it won't know what value result is because it only got assigned within. It's a local

within. It's a local variable. We have not gone through 15

variable. We have not gone through 15 records yet.

No. Can it be used in other? So yeah, it can't be used in other parts of the code as in the variables that got assigned or declared within the function. But if the

value is returned um for example you say answer is add to of seven. Now this answer variable can be

seven. Now this answer variable can be used anywhere because now it's declared outside. It's it's a global variable.

outside. It's it's a global variable.

Any other questions? What does return do? So

questions? What does return do? So

um return is for example you use you call the function add two of seven. Uh the result of this

seven. Uh the result of this function is is nine. The nine gets returned out. So the answer becomes nine. If

out. So the answer becomes nine. If

let's say we had a function of um whatever returns

integer and function and inside uh it said return 25

then I don't know uh potato this would just be 25 because it's the return statement.

Or let's say we're using the original function but instead of um return result we did

uh we did all the addition and all that but we said return 30 40

um then add two of seven would return 40 because we didn't res return the result. We returned 40. I

hope that clears things up. Does nine get outputed or does nine

up. Does nine get outputed or does nine get stored in the parameter? Um so

nine gets gets to be the result. is

assigned to result and then um result is result is returned. So the

nine is returned to the output. Declare is not deaf in Python.

output. Declare is not deaf in Python.

Um deaf in Python you might say is function. You don't really declare in

function. You don't really declare in Python. You just assign the value if

Python. You just assign the value if normal variables.

Okay, I will start on chapter nine. Oh no, back to chapter 7. So yeah,

nine. Oh no, back to chapter 7. So yeah,

we have finished the design part of chapter 7. Um the pseudo code part done.

chapter 7. Um the pseudo code part done.

Now we can really speed things up because pseudo code is the majority of the syllabus. Yep. So in the life cycle

the syllabus. Yep. So in the life cycle you would have coding and coding is development of the actual program in

real languages. So pseudo code pseudo

real languages. So pseudo code pseudo code is a fake language and normally they would just use um pseudo code just to plan. So regardless of what language

to plan. So regardless of what language you specialize in, you would understand this code because they're supposed to be like English-l like statements and they're mimicking real code.

um in testing. So purpose of test data is to check the program works and it rejects any invalid data etc.

By the way, for all the chapter 8 things that is is uh for for all the chapter 8 things that

is that has like M scheme keywords like for example what's the difference between global and local or whatever you think they might ask in chapter 8 you

can check in pup notes for the answer to like actual wording answers like max scheme answers.

So okay back to testing. For example,

the program takes um only accepts integers between 1 and 10. First you would test normal data

10. First you would test normal data like 2, 4 or 7 because it is in 2, four or 7. Uh it is in 1 and

or 7. Uh it is in 1 and 10. There's abnormal data where

10. There's abnormal data where uh it's data that's supposed to be rejected. For example, ABC 976

rejected. For example, ABC 976 uh like that.

extreme data. So whatever is at the edge of being accepted while still being accepted. Now there's boundary data.

accepted. Now there's boundary data.

So if you want to boundary test for accepted values, it would be zero and no it would be a 1 and

10. And if you want to test for it

10. And if you want to test for it rejected uh boundaries then it would be 0 and 11.

Yeah. Now that is coding and testing done in the life cycle onto standard methods of solution.

So standard messup solutions are basically standard sets of algorithm we use to solve problems for like for example you want

to search a value um you don't have to come up with how to search a value every single time people people have thought of the most

efficient way to do so before so you just replicate that method in your language quick definitions algorithm is

a sequence of instructions. Search is to search and sort is to sort. So the first one we have here is

sort. So the first one we have here is linear search. So for example, you have

linear search. So for example, you have a 1D array of numbers and you want to check or you want to search for the number 33. You would go

number 33. You would go along and check each one and boom, 33 is found here.

Uh disclaimer that one I did not make that one I found it from Google. Anyways

example code for so you would loop through uh let's say the the array r has 50

numbers.

So you would loop through the elements from 1 to 50.

And if the number you're trying to find is equal to the value or the element you're looping through, then you have found the number.

Hello. Today now, hello. Today I'll be Oh, okay. Bubble sort.

Oh, okay. Bubble sort.

Um, I will send you guys a link on YouTube if you can't hear the stream, but if you can then just watch the stream. Hello. Today I'll be explaining

stream. Hello. Today I'll be explaining the basics of bubble sword, the swap optimization, and the index pass optimization. So, first of all, what is

optimization. So, first of all, what is bubble sort?

B sort is a fundamental sorting algm that works by repeatedly stepping through a list, comparing adjacent elements, and swapping them if they are in the wrong order. And to make this

easier, let's use numbers from 1 to 5. So let's mix them up

5. So let's mix them up first.

Now what it does is it would flip the first two numbers and check if the current number is larger than the next number. If so,

it swaps. Now it moves on to here whether

swaps. Now it moves on to here whether this is greater than this and five is greater than two so it swaps. Greater than three it swaps and

swaps. Greater than three it swaps and five is also greater than one so it swaps again. Now this goes again three more

again. Now this goes again three more times. Four is greater than two so it

times. Four is greater than two so it swaps. Greater than three so it swaps.

swaps. Greater than three so it swaps.

greater than one so it swaps.

No, it checks. Two is greater than three, which is not true. So, it passes.

Three is greater than one. Yes. So, it

swaps. 3 is greater than four. No. Four

is greater than five. No.

So, then it checks. Two is greater than one. Yes. So, it

one. Yes. So, it

swaps. Two is smaller than three, so it doesn't swap. Three is smaller than

doesn't swap. Three is smaller than four, so it doesn't swap. And four is smaller than five, so it doesn't [Music] swap. Now the list has been fully

swap. Now the list has been fully sorted. And now let's explain why for

sorted. And now let's explain why for the outer and inner loop, we have to go from 1 to 5 - 1. For the outer

1. For the outer loop, the worst case scenario is when 1 or the smallest number is at the

end. This is because the algorithm

end. This is because the algorithm favors the highest number and so higher numbers will be bubbled to the end while

the lowest number would just get displaced to the left. And so the worst case scenario is

left. And so the worst case scenario is when the lowest value is at the end and it has to be swapped 1 2 3 four times.

And so that is why the outer loop goes from one to four and the inner loop goes from also from one to four

because this the first index and it compares with the next second third and fourth and fourth compares with the

fifth and so if it's one to five then it would also compare fifth to the sixth but there's no sixth so an error would

happen. So that's why we go from one to

happen. So that's why we go from one to four and four would compare to five. So now let's explain the swap

five. So now let's explain the swap optimization. This is where we sort the

optimization. This is where we sort the list here. Again five is greater than

list here. Again five is greater than everything. Then three is smaller, four

everything. Then three is smaller, four is bigger, four is also bigger than one.

And then three bigger than two one. Two

is greater than one. And

one. And so even if we might have not done four outer iterations or in this case we might have but it would go through a

loop. It would go through an outer

loop. It would go through an outer iteration again until no swaps has happened. This is

because when there is a swapped that happened, it's the case when a number is greater

than the next. So if each number is smaller than the next, no swap can happen because they are already in ascending order. So that's why no when

ascending order. So that's why no when no swaps happen, the list has been fully sorted and we can end the loop.

[Music] And let's go to the index path optimization. This is

optimization. This is where again I said that the bubble sort algorithm favors the largest

number. So let's say on the first outer

number. So let's say on the first outer iteration four is smaller than five, five is greater than two and five is greater than one. So notice how the

largest number always goes to goes to the end. So after the first

the end. So after the first iteration, we can know for sure that the largest number is at the end because regardless it would be bubbled up and

swapped to the end. And so now we know that the largest number is already at the end. So we can only check so we can

the end. So we can only check so we can just check these four numbers instead of checking all five since we don't we already know this is in the correct

place. So we can just only sort this

place. So we can just only sort this instead. And so

instead. And so now four would be swapped. Four is

greater than one. So it would swap with one. And four is greater than three. So

one. And four is greater than three. So

it swaps with three. And notice how the second highest value is now at the second last place of the list after the

second iteration.

And same for if we check here one and so we can uh only check this after the third but this is already

sorted. The point here is

sorted. The point here is after after x index has passed we can ignore x as much elements

because the largest value would have already went to the end.

[Music] Okay, that is it for the bubble sword video.

Um, now I'll wait for those who went to YouTube because they can't hear the the stream volume. But yeah, does anyone

stream volume. But yeah, does anyone have any questions about

the bubble sort? Also, if you want to like actually see the code, um, you can check the notes, the pub notes in the

embed. Why are you so cool? Thank

embed. Why are you so cool? Thank

you. Pupnotes are in the the bot that keeps messaging or you can type pupnotes in bot spam.

Okay, we'll move on for counting, totaling, and finding an average. That's also considered a

an average. That's also considered a standard method of solution.

So um by counting you uh they mean counting how many iterations have passed in the loop. In totaling you're summing

values when you input numbers for example and finding an average is basically finding a mean. Um although

average I know I mean is a type of average but you're in CS you're not in math so an average is mean. Anyways

um this program oh we'll be going to pseudo code pro so it's easier to explain everything. Uh wrong

everything. Uh wrong one. Oh no I lost my program.

one. Oh no I lost my program.

Okay, let's type it up. I can use pup notes. Hey, look at

up. I can use pup notes. Hey, look at this.

Okay. Yeah. The the whole premise of this program is to enter a number enter numbers and find an average and

total.

So for example, I enter five, I enter 9, I enter 14. Um, and let's stop by entering

enter 14. Um, and let's stop by entering minus one.

And can you like not bother with me right now? Thank

right now? Thank you. Um, it's still bothering me.

you. Um, it's still bothering me.

Please stop. Okay,

stop. Okay, we'll rerun the [Music] program. Five, 9, 14, and let's

program. Five, 9, 14, and let's stop. And so we have entered three

stop. And so we have entered three numbers um excluding the the minus one to quit.

our total 5 + 9 + 14 is indeed 28 and the average is 9.3 also um the reason why I set total to one is

because the last one will ruin the total because we're adding the number to the total and the minus one does count as a

number also I have set count to minus one because um because yeah this minus one will not count as a number. So rather than zero

we're doing minus one. And so we'll go line by line. We

one. And so we'll go line by line. We

initialize a total and count. We keep

repeating this output process and input process. We output asking them to enter

process. We output asking them to enter a number. then input the number minus

a number. then input the number minus one is a way to end end the inputting. So I I use the minus one

inputting. So I I use the minus one system is because for example the next time you might want to enter 10 numbers

instead of three. So yeah, count is minus one because instead of initializing count to zero, um we will have an extra number here

which doesn't technically count as minus one just to stop the program. So

yeah, count equals count + one to increase the count until number is equals to minus one. That's our stop flag.

Um our average of course is total count the mean and we output. That is how

output. That is how you count total and find an average. Next let's find the maximum and

average. Next let's find the maximum and minimum from an array.

So the way I like to do this is for example we have an array of

temperatures 1 to 50. I mean 50 50 days for example so 50 elements and declare the minimum and

maximum we'll set the minimum and maximum to be the first value in case it is and even if it isn't uh that value will be overridden later.

So now that we have already started at one, we'll be starting count at two. Oh,

the arrow's gone. I should fix that in pub notes, too. Um for 2 to 50. And

50. And if if the current temperature at the index count is bigger than the current

maximum, then it becomes the new maximum. And then if temperatures

maximum. And then if temperatures um at the index count, so the temperature we're looping on is less than the minimum we originally thought

we were uh having, then the new minimum would be the temperature at the index count and we'll continue looping through

count. And lastly, we'll output maximum

count. And lastly, we'll output maximum and minimum temperature.

Oh yeah, note that you could also do from four count arrow 1 to 50. Um, and

if you want to do that for maximum you have to say - 999 and for minimum you have to say 999. Uh, so it gets immediately

999. Uh, so it gets immediately overridden by um the maximum or the minimum but I just

like to start at one because you know it's it's a waste of time.

Okay, we have finished standard methods exclusion. Again, you I'll finally

exclusion. Again, you I'll finally answer uh questions at the end of the chapter. And now we're on to validation

chapter. And now we're on to validation and verification checks. With

checks. With validation is basically checking the input is proper for your program.

For example, you're asking for um a student's mark maybe as a percentage or maybe just a test that is

out of 100. And so

um you would expect the number to be zero and 100, right? So you can use a range check. You ask them to enter

range check. You ask them to enter student marks. You input it and then you

student marks. You input it and then you keep doing it until it satisfied the condition. This condition being the

condition. This condition being the marks is greater than zero and less than 100 aka it's between 0 and 100

100. Next there's the length check. So

100. Next there's the length check. So

if you want for example the password to be exactly eight characters then you keep entering the password until the

length of the password is eight.

Um, then we have to type check if we want to check the input is a specific data type. Although technically you're

data type. Although technically you're in the gray area here because you can't really determine a type of things for

Cambridge pseudo code.

Uh the only question they might ask here is by asking you to enter a whole number and if

um if it's not a whole number you can ask it ask to enter it again. The reason

this works is because for example um you do 2.4 for mod. M mod mod is

getting the remainder, right? Divisor

dividend um equals whatever. And so you're trying to get the remainder. If you're trying to divide

2.4 by one, the remainder would be 04. But if you divide a whole number by

04. But if you divide a whole number by one, let's say 10 divided by one, the remainder would be zero because it perfectly fits to 10.

That's why you can check if it's a whole number or not. Or if you want to count it an integer, you can I guess. Now let's continue with

guess. Now let's continue with validation. So you can check the

validation. So you can check the presence. Um enter your email address

presence. Um enter your email address and if the we enter until the email address is not blank. This sign being not equal

to the format check is where you're checking it to be a specific format like for example a serial number or code to

be begin with ABC. So please enter serial number and we'll take the three charact first characters and check if it's

ABC. Um this works because one is the

ABC. Um this works because one is the start index. So this is the first

start index. So this is the first character and you're using three um length three. So first, second and third.

Now the check digit um check digits is typically on barcodes and it's how you it's when you

calculate um all these front digits and then put it into some random algorithm or some calculation method and

you would get a check digit at the end three. So now when let's say a cashier,

three. So now when let's say a cashier, the accountant or whatever you call them, um they type in the book code or the barcode,

whatever. Uh assuming they can't scan it

whatever. Uh assuming they can't scan it cuz the barcode got damaged or whatever, they they enter all the code, we would

get the the first digits except the last one. So I'm doing minus one here. And

one. So I'm doing minus one here. And

we're calculating the check digit by some unknown function named calculate.

This the unknown function.

Um and we check whether uh the the last digit which the last digit would have

the position of the length of the string um of length one. So just one digit here is equal to the check digit we just

calculated. This code you don't need to

calculated. This code you don't need to know because there is no algorithm you're supposed to know for check digit.

So basically you're using all the first numbers to calculate a last number. So

then next time you reenter the the the whole code you can check whether the last numbers is the same. If the last number is the same that means there you

didn't mistype it. Now in

it. Now in verification you have to you want to ensure the data is copied uh correctly

from one source to another. For example

um for your brain to to the password entry uh place. So you can do a visual check

uh place. So you can do a visual check or double entry check. These are two types of verification.

The visual check is where you look at it. You tell the person to look at it

it. You tell the person to look at it and yeah that's a check. So you can press the I button for on the password for example or for the double entry check

you know when you typically go make a password it would ask you to enter the password again just so they know that you have entered the correct password

when you set it.

This would be the code for um visual entry, you know, outputting the password for them to check and type yes to

confirm or uh entering a password, entering another password, and checking if they're the same. So that's the double entry

same. So that's the double entry check. Now lastly, in chapter seven, we

check. Now lastly, in chapter seven, we have choice tables.

So um basically you have a flowchart or pseudo code given to you and you're trying to trace the values

throughout the program. This is my easy formula. So

program. This is my easy formula. So

initialize the variables then mostly they're loops. So write the

they're loops. So write the corresponding values etc. I'll go I'll go through it with you guys. So here complete the trace table

guys. So here complete the trace table for the input data. Normally I try to understand what

data. Normally I try to understand what the code is first. So let's see

um it initializes total of zero and then account of zero and then it wants us to input a value

then so I assume this is some totaling program or yeah I see here average so probably both totaling and averaging um if the value is zero it's going this

way that means it when you type zero it wants the program to calculate an average

and re output the total and the average or if it's not zero then we continue if it's minus one then it's a stop so as

you can see normally you stop when it's minus one and then if it's the regular value so it's not minus one you just total up the value and you increment the

count it would go over and So let's see let's say 25 25 is a normal no let's start with initialization right

so they started at zero here and zero here now um 25 as a value inputed so it'll be

here and the value is not zero so we're not doing all this fancy stuff it's not manified so we're continuing

And total would increase by the value and the count would increase by one. So total would increase by 25 and

one. So total would increase by 25 and count would be one. Next

one. Next 35. Sorry about my

35. Sorry about my handwriting. Um that's

handwriting. Um that's 60 and then it would be two. Next is three.

two. Next is three.

Sorry.

Oh and uh 63 and the count would be

three and zero. So, we're now averaging and totaling.

So zero average is now calculated 63 / 3 is 21 and you don't have calculators in

this exam. So

this exam. So um yeah good luck with that. Then total is

that. Then total is uh outputs the total and outputs the average. the

average. the output. No, it doesn't output the word

output. No, it doesn't output the word output. What am I

output. What am I doing? Oh,

doing? Oh, sorry.

[Music] Um, total is

63. Calculators are not allowed. Yes.

63. Calculators are not allowed. Yes.

um the average is 21. So you go on the next line here

21. So you go on the next line here because you're outputting again. And then

again. And then um you've seen you you guys have seen me do this so I won't continue with that.

But please remember um when you see minus one it stops. So

sometimes they give you extra values, but if if it stops the program, then you stop. They like to catch you on the

stop. They like to catch you on the minus one. I've seen minus one in so

minus one. I've seen minus one in so many flowcharts. So yeah, be careful

many flowcharts. So yeah, be careful with that. Um the answer, yep, the first part

that. Um the answer, yep, the first part we did correctly. Yeah, it ends at minus one. Careful with

one. Careful with that. Okay, we have finished chapters

that. Okay, we have finished chapters seven and eight. Any questions?

Um, one of the most asked questions was in the um, average totaling and counting pseudo code, why was count minus one?

They didn't seem to understand that part. So, if you could revisit that,

part. So, if you could revisit that, this one, right?

Yep. Okay.

So, [Music] um for example, we made count to zero. We start

at zero. That's that's supposed to be normal. Uh, let's say we add we want the

normal. Uh, let's say we add we want the number five, we want the number four, we want the number three. So now the total

would be 12 and the average would be four and then we want to quit. So we do minus one by quitting to

quit. Um total is 12, average is three.

quit. Um total is 12, average is three.

Good. But the problem is no average is not three. Average is four. The problem

not three. Average is four. The problem

is that it thinks that the amount of numbers we entered is four because it counted the minus one here.

So then that made the count now four. So

then 12 gets divided by four to be three rather than the numbers entered being three and the average actually being four because 12 the average of this

obviously is four, right? Because it's

the middle value.

Okay. Any other questions? Why did he add the first value? Yeah, that one in the second line.

So, are you asking why I'm only putting it on the second line rather than

first? Or are you asking why I'm totally

first? Or are you asking why I'm totally like 25 to 50? Why the second line? Okay. So,

50? Why the second line? Okay. So,

um questions typically have initialization like zero um and zero of total and count that's

outside the main loop. This is the main loop. We've been gone through like total

loop. We've been gone through like total and counting, right?

Um, and if you're initializing some values outside the main loop, then uh you do that on the first line, then

you do all the loop stuff on the second line or third or whatever.

Yep. Okay.

Isn't it better to use while loop for totaling and averaging? Did I not use a

averaging? Did I not use a while? Oh, I use a repeat. H either

while? Oh, I use a repeat. H either

works. I just like to do um a repeat especially when you have minus one because it's pretty clear like you're you're repeating until you get a

minus one, you know. Any other

know. Any other questions? Does repeat take one more

questions? Does repeat take one more step than a while? Um

so sometimes it does, sometimes it doesn't. The main takeaway is repeat

doesn't. The main takeaway is repeat checks for the value after the loop whereas while checks before. So that

means that repeat will uh guarantee if I can find

repeat.

Oh yeah.

Um see you're already repeating. you're

already doing the stuff. But while

loop checks here and then does the loop, that means if the first time they enter the

password up top here is already 1 2 3 4 5, then it won't go in the while loop because you're already testing the condition

here. Whereas here, you're doing

here. Whereas here, you're doing whatever first, then you're checking here.

Any other questions? I'll move on to chapter nine

questions? I'll move on to chapter nine then. Okay, chapter nine is all about

then. Okay, chapter nine is all about SQL.

So um first I'll introduce you to single table databases which is all you'll do for IGCC computer science

SQL and then um how you should suggest basic data types and what a primary key is and how

to suggest the suitable one.

So here is a single table database. It's

database. It's basically it's basically like a collection of data um in in a table in one table right

because single table and for example in this case we want to keep data of different customers. So their first name, their

customers. So their first name, their last name, their country. This the column

country. This the column um Cambridge likes to call it a field and the row is called a record. So

one record of data is Maria Kramer from Germany that has customer ID 1 and the field would be the field of first name would have you know these

different first names. A cell, a data item, a column value, um is just one

rectangle and a table is everything. Now, if we want to suggest

everything. Now, if we want to suggest suitable basic data types, first we'll have to see what data types are even available for us, right?

Um so the first data type that is available is what text and alpha numeric. These

are two different things. The text data type is a collection of characters.

Um so it can be English alphabet, it can be spaces, it can be emojis, whatever.

Alpha numeric on the other hand uh can be only letters and numbers not spaces not emojis not special characters. So that's the difference. So

characters. So that's the difference. So

keep that difference in mind because Cambridge likes to trick you a bit.

Um when they want you to suggest a suitable data type. Sometimes it's

interchangeable. A lot of the time it is. But just please know the difference.

is. But just please know the difference.

Text you can include the number. Text is

like a string. You can include anything in text. But alpha numeric only letters

in text. But alpha numeric only letters and numbers. A character is one single

numbers. A character is one single character in one in single quotes. Um a

b c whatever in lower or uppercase. It can also be special

uppercase. It can also be special characters. Now boolean can it's just

characters. Now boolean can it's just two valid states true or false. yes and no

or anything that has two valid states not just these two because it's SQL now rather than code. For example, in a past

paper, um there was an SQL table with horses and it included the gender with M and

F and you would call it boolean, not a character because it's not even true or false, but it's M or F. So, you know, to

validates rather than a character. Not that these are gender of

character. Not that these are gender of horses. I am not making any comments

horses. I am not making any comments whatsoever.

Um next we have integers which yeah integers whole numbers but also negative numbers zero

whatever real um any type of numbers including fractional or decimal or whatever date and time they're often

interchangeable for Cambridge IGCC um date being a date time being a time

and time hasn't come up often or at all I don't think in past papers but yeah minus 5 is a real it's a number

yeah an example for suggesting data types let's say we have a game store with different games

um game ID name and description okay I I'll have you guys suggest what Each field game ID name description should have

um as a data type. So, first game ID.

What do we think? Alpha numeric

think? Alpha numeric indeed. It could be tax, but Cambridge

indeed. It could be tax, but Cambridge would way prefer alpha numeric because um first, you know, you only need

letters and numbers. And second is so you know, you're not mistyping something like a space or whatever cuz spaces aren't even possible. And third is it

saves memory because you only need you need lower data to lower number of bits to

represent only letters and numbers rather than all characters and spaces and everything. Name. What do we think?

everything. Name. What do we think?

name text text string string text text so the answer is text there is no string in SQL keep that in mind there's only text in alpha

numeric and I won't waste your time you know description is also text because there are spaces definitely Okay,

now let's learn um what our primary key is.

So let's see the purpose, right? Let's

say we have a restaurant, a a taco shop.

There's three customers, John Gondo, Sarah Johnson, and John Davis.

Um, and when we're keeping the names, we're keeping their first name and the initial of their last name. John D,

Sarah J, and John D. Now,

D. Now, um let's say they they come up to you and ask how

much how how many tacos have John Davis eaten? right here. You won't even know

eaten? right here. You won't even know because there are two John D's. It could

be John D, John Davis or John Doe. So

that's why now we have what you call primary key typically is some sort of ID

like customer ID. Um 1 2 3. So now John Doe could be number one and John D could be number uh John Davis could be number three. So they would know what customer

three. So they would know what customer they are.

And yeah, this is the mark scheme description. Um, it uniquely identifies

description. Um, it uniquely identifies a record. So, you know, a customer

a record. So, you know, a customer whatever the case study is.

And the primary key would be different for each record. That's that's the main point of it.

read, understand and complete SQL scripts to query data. So querying is

data. So querying is searching searching in the database.

Let's say you have a table called dog books and you want to um get the name of

descriptions of the books.

So you would select name and description from all the dog books. The

table name being dog books. So you're

getting the name, the description, these two fields from the dog books and you would get these. You could also do select asterisk

these. You could also do select asterisk from do dog books and asterisk is a wild card and that means you want everything.

So you get book number, you get name, description, news, truck left, and you see why that might be useful

um in a bit. But yeah, now what if you only want new type of dog books? So the

golden retrievers and the chibatu um dog books are are new in stock or whatever. And what if you only want the

whatever. And what if you only want the new ones?

Well, you can use the wear clause and you can check whether it's new. This

would be the same as new equals true.

But since it's already a boolean, you can just write where new. That's the

same for if conditions in the in pseudo code by the way. But

yeah, and the result you would only get the name and description of new dog books. New is true. these two

books. New is true. these two

dots.

Now, how do we differentiate between Okay, that's a very solid point.

[Music] Um, you don't have like in um in in SQL or in in Cambridge, I mean

Cambridge IGCC. So, there's only equal.

Cambridge IGCC. So, there's only equal.

Anyways, the wearer clause. Let's

continue. What if you only want new books that are 200 in stock? So you want new and you want 200 less than 200 in

stock. So you would search new and less

stock. So you would search new and less than 200 in stock. Um just like pseudo code you can use and you can use not you can use

uh or and yeah it would only be golden retrievers because it's true and 192

whereas this book is new but not less than 200 stocks. Now you could also order your

stocks. Now you could also order your query. For

query. For example, oh sorry um you can get all the doc books name

and description and or ordered by the name. So originally it was Pomeranians

name. So originally it was Pomeranians golden retrievers and beagles. Now it

starts with beagles because it's a B then yeah etc. And

also you can order by multiple fields for example first name and last name of let's say a

customer customer table. And so in this case you would first go by the first name. Um so Adam would be first then the

name. Um so Adam would be first then the two John's then let's say descending last name.

um Smith because an S and then D because an the O is before an A, right? And so that is how you specify

right? And so that is how you specify whether it's ask or whether it's desk is yeah or ascending or descending is by labeling those

two. Now let's say you wanted to to know

two. Now let's say you wanted to to know how many books are left. You can sum the stock that are

left and you would get 810. How many types of books there are?

810. How many types of books there are?

You select and you count and inside the count you put an asterisk um from the table dog books where there are new. So basically, you're trying to

are new. So basically, you're trying to count how many types of new dog books there are, which there are two because it's just golden retrievers and

jibu. And

jibu. And um question you might want to ask is why the asterisk? Asterisk normally

the asterisk? Asterisk normally represent like all the fields.

But in this case, um, you would always use an asterisk because if you labeled a field, there's really no point because,

um, counting only a field just basically does the same thing but exclude values that are empty. But in IGCC there aren't

any empty values. So yeah, just always count asterisk. Also, um when you order by

asterisk. Also, um when you order by order by name for example, by default it's ascending. Just pointing that

it's ascending. Just pointing that out. Now we go on to the summary.

out. Now we go on to the summary.

So the select statement is to choose the fields or the sum or count function to display. The from clause is to choose

display. The from clause is to choose the table, but you only have one table because you're doing RGCC, so don't worry.

Um, the wearer clause is the condition.

Order by is to choose what field you're ordering by. and ascending or descending

ordering by. and ascending or descending sum and counts. That is it for chapter 9. Any

counts. That is it for chapter 9. Any

questions? If we write ordered by name would be ascending or descending. It

will be ascending. Ascending is

default. Any other questions?

There was a question can we and if so how uh set des desk or ASC in order of

numbers can we set descending or ascending in order of numbers what wait I'll send the message down Oh yeah, numbers. Yes. Yes. Yes.

Sorry. Let's say

um we we can order by the stock left for example. Um so stock left ascending

example. Um so stock left ascending would be 102 then 142 then 192 then 374. Has anyone written notes? Um, all

374. Has anyone written notes? Um, all

the notes you will need is in pup notes.

It that is being constantly sent by the bot. And yeah, it will be also recorded,

bot. And yeah, it will be also recorded, but just check notes because it will include some mark scheme descriptions especially in chapter 8.

presentation will be sent um in the computer science channel um pinned soon pop notes. Yes, there

pop notes. Yes, there is. Okay, let's go to chapter

is. Okay, let's go to chapter 10. So, first I'll have a bit of a tiny

10. So, first I'll have a bit of a tiny preface to chapter 10. Then I'll teach you guys the uh how to identify and use

the standard symbols for logic gates.

Then define and understand the functions of logic gates. Then um solving different

gates. Then um solving different scenarios.

So oh sorry.

So you might ask why even logic gates? Um the reason is in in the CPU or

gates? Um the reason is in in the CPU or in the computer you're storing you're storing whether it's a zero or one bit

um with these little transistors. And with these transistors

transistors. And with these transistors you can make a circuit that will add up to a very big circuit. And that means you can add stuff, multiply stuff and

then eventually run all these programs. Yeah. Now

Yeah. Now uh I will teach you the different types of logic gates and then we will combine it to a logic

circuit. The first type is the

circuit. The first type is the notgate. So it will just output the

notgate. So it will just output the opposite value. For example, um not zero

opposite value. For example, um not zero is one and not one is zero. So let's say this is called a truth table. Um

basically the values corresponding to each other. Our variable here is a 0 and one.

other. Our variable here is a 0 and one.

The result of not a would be one and zero because yeah they're the inverse for the and gate

um it would output one if both are one example a and b are one zero and zero no they're not um they're not both one so

the result is zero zero again zero again and one one so then it will become a Now types of logic gates we have the

orgate. So if either one is one either a

orgate. So if either one is one either a or b is one then x will be one. So you

can see here one one one one one. Um the

one. Um the norate if neither uh neither a nor b is one then x will be

one. So this will only be true when

one. So this will only be true when they're both zero. The nan gate

zero. The nan gate um if both aren't one

uh it it will be one which is essentially just not of a and b which basically means

um you know everything but when a and b are one it will be zero.

XR gate exclusively or so A or B but not both then it will be a one that's why it's called X or exclusively A or B but

not A and B so does it for logic gates now

um why so yeah they're used to there they are elements of a logic expression or a logic circuit giving one as output

and they're used to control data flow with like the AOU for example the arithmetic and logic unit you're trying to calculate things so you um make

circuits and do them and I'll show you a little demo of how they're used.

So let's say this is A, this is B, this is C. This is an ANDgate. This is a

is C. This is an ANDgate. This is a NOTgate and this is an OR gate. So

gate. So um since this is an O or gate uh either this part is true or this part

is true, the light bulb would turn on.

So this is the and gate. You need both for this to come on and this would be true or this not zero being one. So it

will already be true making it true or both. Um, I'll send the website here.

both. Um, I'll send the website here.

But yeah now for exam questions or scenarios um I'll introduce the most important

ones especially with logic expressions because if you know these these are called logic expressions, by the way, the the wordings. And so, if you know

how to do the words, then you'll likely know the equivalent drawing or um whatever of

it. They want us to draw this whole

it. They want us to draw this whole thing.

And what I normally like to do is I I focus on um the gates that are touching the

variables. For example,

variables. For example, um we start with not a so stuff that is directly impacting a rather than this and in the middle of

everything.

um or B and uh we'll skip that for now. B

exclusively or C [Music] um X or being the same thing but just with a line

across. And we combine these two

across. And we combine these two with an and. Yeah. And gates are just the flat

and. Yeah. And gates are just the flat version of or. Boom. We draw the logic

or. Boom. We draw the logic circuit. Yes, you can curve the

circuit. Yes, you can curve the lines. Technically, it's a bit better,

lines. Technically, it's a bit better, but as long as the examiner can read, they don't mind.

Now yeah we got it correctly and here are the labels.

So split it um into two parts and here and then we combine it and then yeah the result is

here and um let's complete the truth table. So

uh sorry we have oh the logic expression here [Music]

um not so what I like to do the easy formula TM um is break them into different columns then combine it. For

example, we want the first part and we do that by um first figuring out not A.

So no I mean sorry um by not A or B. No yeah yeah no not A.

So we break them into this and each different parts. Um, not a being one

different parts. Um, not a being one one 0 0 0 or

B. So, let's call this D for now. And

B. So, let's call this D for now. And

then D or B because we're combining not A with or B.

Um, and so if it's an or then if this is true, then this would also be true. and

also or B. So B is true in these last two and yeah neither. Now we want B, X or

neither. Now we want B, X or C. And

C. And so either but exclusively either not both. So Yep. Yep. This is both. So you

both. So Yep. Yep. This is both. So you

can't um here you can you can one here you can one one you can't and then let's call that

[Music] um F and let's call that E and this would be everything combined.

So E and F and so it would be something

like sorry um E and F. So it would

be zero. Um this is an and so one

be zero. Um this is an and so one one 0 0 both ones. So one because it's and

zero. Yeah, we got

zero. Yeah, we got it.

Um then a logic expression from the circuit.

So let's start from the first first inputs from the left then to the right. So

right. So um I will note it here because it's easier. X equals not a because we have a

easier. X equals not a because we have a not get here and then not a and

b and then this too far. So let's go back to here. Um we also have not

C and between these we're oring it. So

or so this would be the final answer and yeah this should be the last one and then we can go to

papers. So

papers. So um how do we find the logic expression from the truth table? We can do

that. Oh sorry

that. Oh sorry [Music] um by checking the rows that make it

true because yeah because that's that's the final answer. That's the result. We want

final answer. That's the result. We want

to see what made it true from these three and they don't want they don't want us to simplify at all. So the first

way that would make it true is by a and sorry I'll just type it.

The first way here would be A and not B and not C. The second way at the bottom

is A and B and C because they're all true. And so it's either either this way

true. And so it's either either this way or this way. You know what we can do? We

can put an or in the middle of everything. So

everything. So now it would be something like this.

You might think it's a bit long, but um they explicitly told us not to simplify.

So yeah, that is the final answer according to the mark scheme. And that is it for chapter 10.

scheme. And that is it for chapter 10.

I remember seeing a question. In the

question, if I wanted a line to go from A to C, would it intersect B or do I make it behind? I do not know what you understand by this

question. Do we have any other

question. Do we have any other questions? Thank you so

questions? Thank you so much. Um, it's not the end by the way.

much. Um, it's not the end by the way.

We have a test paper of paper two coming on. X nor is not in the syllabus so you

on. X nor is not in the syllabus so you cannot use it. We only rewrite and on that last

it. We only rewrite and on that last topic. What do you

topic. What do you mean? If two lines

mean? If two lines intersect then you make the intersection clear. Okay. Okay. Well, we don't have

clear. Okay. Okay. Well, we don't have any um for example just show you with the circuit I

guess.

Um let's say this didn't exist and um how do I get rid of this? Okay. And then this became this

this? Okay. And then this became this and this had no this is a knot.

Sorry.

Um and yeah, so just just cross the lines. It it as long as um the examiners

lines. It it as long as um the examiners can tell which lines go where and you're making the intersection clear, then that's fine.

Do we have to form the logic is from only truth table? Well, let's check this wonderful

table? Well, let's check this wonderful note section, shall we? Do we have to form a logic circuit

we? Do we have to form a logic circuit from truth table? Logic is to find a logic from a truth table. Yes, you do.

Um, in the notes I only included mostly for logic expressions because there would be like 10 or nine of these. But

yeah you do. How convenient

do. How convenient indeed. Couldn't it also be A or B or C?

indeed. Couldn't it also be A or B or C?

What do you mean?

Um anyways uh please clarify on that question but I got another separate point is for this question um you have to leave it like this. There

is no other way to do this. just find

the rows that will end up in a one and just or them. That's the only way. If

you somehow find an easier method or whatever, um you you'll get cut you get marks cut off you because that's not the way they

intended to. So yeah, and they said do

intended to. So yeah, and they said do not simplify. So they want you to find

not simplify. So they want you to find the combinations. Bobby, you'll never be

the combinations. Bobby, you'll never be asked to simplify an expression, right?

Yes, you will not be and you shouldn't at all. You should see the rose and what

at all. You should see the rose and what makes it true. Never seen it. Yeah.

So never simplified even if you know how.

Any other questions? Okay, let's do papers then.

questions? Okay, let's do papers then.

Yay.

That was a while. Papers, papers,

while. Papers, papers, papers.

Okay.

Verification is used to make you lot.

Yeah. Um is used to make sure a value is entered has not changed during the input.

While validation is checking is suitable for the program.

Um the type of validation. Okay.

So a type of validation would be a length check. They want in this

check. They want in this style. So what would be the validation

style. So what would be the validation check? this case it would be um the

check? this case it would be um the format check because we're checking it's in the date, month, and year style. And

style. And um would type check be correct? No, it

would not because they went to certain style and you can't do that by just checking it's a string.

one example of normal test data and the reason. So,

reason. So, um let's say 01 uh 1100 because that's a normal

date or something like this.

[Music] um abnormal. So

abnormal. So uh 1st of January 2000 that is not

accepted because that is not in the proper style.

Don't the reason seem a bit too vague? Um, well, let's see the

vague? Um, well, let's see the mask. A, that was correct. Format check.

mask. A, that was correct. Format check.

Yep.

Look, the only thing they care about is the the they should be accepted. You can add whatever, but

accepted. You can add whatever, but yeah. And

yeah. And rejected. So yeah. Um mention the word

rejected. So yeah. Um mention the word accepted or rejected. Describe how a length

rejected. Describe how a length uh how a length check could be used with the data entered.

So a length check could be used by checking

the date entered is 1 2 3 4 5 6 7 8 9 10 10

characters long because if they're matching this format then that means you know they included the the two date

digits, the two months digits, the four year digits, and um the two slashes.

Now, how should we make it two marks? Well, let's

marks? Well, let's see. Oh, yeah.

see. Oh, yeah.

um projected if too short too long because it's not in the valid

style. Can the space also be counted?

style. Can the space also be counted?

Yes, space is included in the length check. The length check just checks the

check. The length check just checks the number of characters. Okay, this is fun.

characters. Okay, this is fun.

draw a pseudo code statement that would um to the most appropriate pseudo code use. So let's say counting which one

use. So let's say counting which one would count. This one would definitely count

count. This one would definitely count because we're incrementing by one each time.

finding an average I mean pretty clear we're summing up and then dividing that's a mean and then totaling

um we're not toting anywhere these this is five not all pseudo code uses will be required using a conditional statement

that and then using a procedure that [Music] um and both here and in logic circuit

questions you guys have to make sure that the intersections are clear because let's say like this and let's say

totaling was I don't know intersecting that either like um just you know be be

good give the examiner a break let them fast. Okay.

fast. Okay.

Now they want us to find the minimum temperature from 25 elements. Let's

see.

So the temperature is already declared.

They already have values in it. So we

don't need to do anything.

[Music] Um let's declare the minimum being an

integer and uh let's also declare the count because we'll be looping soon I hope.

Um yes I do not need to declare the array but I do have to declare the rest or assume sometimes sometimes there are mocks for declaring sometimes there

aren't I don't know minimum like my favorite styles I like to do same thing as the first one then starting as the second because if the

second one is slower then it gets overridden anyways.

Um for count from 2 to 100 because we have 100 no we have 25 elements sorry and we will

uh check if the temperature is at the count is less than the minimum or the current minimum we know of

then That's the new minimum because that's actually lower. And if

lower. And if uh next count and then output the minimum

is this minimum. I hope

minimum. I hope um yeah indeed. See how most people will set it

indeed. See how most people will set it to a randomly high value so then it gets compared and then the first one becomes lower. But this is also accepted because

lower. But this is also accepted because you're being more efficient here.

[Music] um different cities.

So what does it want to do? Find errors

and suggest corrections. Okay, let's go

corrections. Okay, let's go through city does not have a colon here.

[Music] Um that's weird. Although there's already a

weird. Although there's already a boolean, so yeah.

So, although I don't know whether not being a colon here is me downloading it wrong or Yeah. something. When you're done,

or Yeah. something. When you're done, can I send? Yes, I

can. Um, yeah. No. Colon. Maybe. Maybe

not. I don't know how I downloaded it.

And then also um boolean type because glancing through here it's already clear that the name of the city

or the country whatever is going to be a string because it's the it's a name. Um okay. Now let's go back to

name. Um okay. Now let's go back to actually understanding the code.

So we're counting. So, it seems like we're looping through something.

Um, line number. You don't need to write any line numbers. Oh, that line number.

I mean, you can Yeah, you should probably um This is very rough. Type declaration

for city array line 01. Yeah.

01. Yeah.

to label the line number. Thank

you. And so the correction would be something like

this of string. Oh yeah. What what does the program do? The program seems like we're looping. So this is definitely

we're looping. So this is definitely wrong.

Um, oh, here it already tells us, sorry, allows the name of 50 cities and the countries to be entered and then it's outputed. Okay,

that's cool. Oh, yeah, we're doing some kind of

cool. Oh, yeah, we're doing some kind of loop here, there's until, so this has to be repeat and then um since city is being entered first,

this should probably be one and then two.

For reference, I assume what is going on here is there's a 2D array with city and

country. And so you'd have the name, the

country. And so you'd have the name, the country, the name, and the country, the name, and the country. So this would be 1, one. Um

country. So this would be 1, one. Um

this would be 2 one second row first column 3 one third row first column or one two

2 3 two for example and so both ending in two is wrong.

Yeah. Anyways back to how it was an if rather than um a repeat.

So if instead of repeat line uh 05 and

then repeat if to start a loop or whatever

error three so yeah I pointed out why is there a two rather than first? Because

city is supposed to be first.

Um two uh input city count two shouldn't be column two

line 07. Note that you should probably write

07. Note that you should probably write in better English than this. I'm just

you know going through the fashion [Music] um

declare no not declare input city count one this will be recorded and uploaded.

Yes. Um the last error count + one for out why is it looping from 1 to one? It

should be 1 to 50. So

yeah. And yeah, you can see here the city is definitely coming first because you're outputting like this.

And we have 50 city and countries.

[Music] Um, describe changes you would make to allow a city, a c the name of the

country to be input and to display um only the stored cities from that

country. Okay, let's see.

country. Okay, let's see.

So we want to first um oh we don't want to rewrite the

algorithm. Okay. So we want

algorithm. Okay. So we want to declare a variable for the in for the

chosen chosen country name as a string

then output out and in the country of choice.

Um then we want to implement uh linear

search. Wait,

search. Wait, no. Allow the name of an

no. Allow the name of an algorithm. Oh, the cities are actually

algorithm. Oh, the cities are actually stored.

Sorry. Okay.

So remove input of city name and the output prompt.

[Music] Um add [Music] uh uh change from repeat

until no [Music] uh change from until until 50

to first inputting um whether where the user wants to stop

entering the country name then until the flag is true or they want to stop

entering.

Um then implement linear search for the country

um to check. Okay. Well, now now the country

check. Okay. Well, now now the country names would also be already stored.

Yeah, we so yeah we are assuming the array has all the countries and all the cities stored and they want to enter the country name and we want to give them the city name back. Yeah, it's a bit

hard. Sorry.

hard. Sorry.

um input country name. They want to find rather than

name. They want to find rather than inputting to the array to the array.

um to check to find the country then

output the corresponding city with the same index slashc count slash row.

[Music] Um I think that is what they mean. Let's

see.

That's the fixed one. One, two, three,

one. One, two, three, four, five. Why are there

four, five. Why are there five? Oh, these are combined to two

five? Oh, these are combined to two marks. Okay, then I completely skipped

marks. Okay, then I completely skipped this.

Sorry. Um, it should either start at zero, uh, count should either start at zero.

So then it actually be, uh, becomes 50 instead of 49. Um, or until count is greater than 50. Now, yeah, country to be searched. Oh, please do label the

be searched. Oh, please do label the position. I forgot about that. Using a

position. I forgot about that. Using a

new variable. Yep. Um, add an if being searched. And if it is then

searched. And if it is then um I put the city cool variables and constants.

So consents should be consents should be assigned to a literal

whereas variables can be changed throughout the program which can't be changed

throughout the program.

Constants should be used for a specific value that will remain the same.

Eg mass constant like pi. variables

um should be used when calculating a new value or inputting value. Sorry if I do not have the

value. Sorry if I do not have the correct mark scheme wording. I am no longer the prime puppy.

Oh yeah, they should. They're both used for data

should. They're both used for data storage.

Programmers they should have meaningful identifiers.

Yes. And programmers should be able to understand. Yes.

understand. Yes.

Is it important to identify both variables are named data store?

Um I just say that they have meaningful identifiers. Yeah, same thing kind

identifiers. Yeah, same thing kind of flowchart. We're traceabling again.

of flowchart. We're traceabling again.

Let's go. I will screenshot this so it's

go. I will screenshot this so it's easier to see.

The question wording did not help. So,

let's see what's happening. Um, oh, it's the one we just

happening. Um, oh, it's the one we just did. Sorry. Well, you got the answer

did. Sorry. Well, you got the answer now.

Describe the purpose of the algorithm.

Um inputting uh multiple values until stopped with minus one. Then

minus one. Then uh I'll putting the total and putting the

average.

Sorry. Oh, I did not read. Okay.

Um, be careful of this as well. This zero actually goes back to

well. This zero actually goes back to the first rather than here. So, so

you're retoing everything when when there's a zero. And yeah, well, I get two marks

zero. And yeah, well, I get two marks calculating the average and outputting, but yeah, careful. Careful.

write pseudo code. Looks like we are doing some

code. Looks like we are doing some substring. Okay, let's

substring. Okay, let's see. So,

see. So, um it's explaining what substring is.

And now they want us to start a string the string in the quote. Let's do that.

Um in the quote variable string no

quote is learning never exhaust the mind. Yes it does. Anyways um let's

mind. Yes it does. Anyways um let's extract the mind.

[Music] So uh phrase is

substring of quote and frame the start index.

That's 1 2 3 4 5 6 7 8 9 10 11 12 13 14

15 16 17 18 19 20 21 22 23 24 25th. T is

25th. That's the start index. And then let's see the length. So

index. And then let's see the length. So

um 1 2 3 4 5 6 7 8 25 and 8.

Oh, and they want the lowerase version as well. So let's out key

as well. So let's out key that. And then let's output the

that. And then let's output the phrase.

Um yeah, you don't need to um assign the start index by the way or the

length. They they allow you to just use

length. They they allow you to just use it correctly. And yeah, use of substring

correctly. And yeah, use of substring use of L case.

Oh, they want you to display this too.

So, display the phrase first.

Sorry. Need to declare phrase. Indeed,

we do.

Okay. Now, why do we use procedures and parameters? So, procedures are used

parameters? So, procedures are used Um then we use sets of statements

or code throughout throughout the program.

This um means code gets repeated less often and

um is easier to read and more [Music] maintainable.

Any fixes to the set of code would also apply throughout the program.

Parameters are used to take in values from the main program

to the parameters. This means

uh the procedure can be reused with different parameter values. Let's

values. Let's see collection of programming statements. So yeah,

statements. So yeah, um keep that in mind. Allow modular

programs reused. Yep. Creation faster.

not really um make program shorter, less duplication of code. We said less repeating. So yeah, that's cool. That's

repeating. So yeah, that's cool. That's

easier to maintain to pass values from the main program. That is indeed

program. That is indeed um taking in values from the main program. That's what the parameter

program. That's what the parameter does. And like the function return gift

does. And like the function return gift I'm about to show you. Yeah.

And so that the so that it can be used and different data.

Yeah. Now they want us to draw the following logic expression. So

let's do that. Um let's draw it in paint actually

that. Um let's draw it in paint actually because that's a lot easier.

[Music] MS paint. I love

MS paint. I love it. A NAND

it. A NAND B. Good point is that NAND gates or NOR

B. Good point is that NAND gates or NOR gates just is nan but with the with the circle after.

Um, and then Bx or C. So, let's do that first with a cross here. Then we knot

here. Then we knot it. And

it. And then we or everything.

Um that is it for the bullying and complete the truth table.

So, let's use the um easy method. Let's do it here as

method. Let's do it here as well. Delete that

well. Delete that first. Um N and B

first. Um N and B That would be um and is 0001. So it would be 1 0 0 0.

That means only when uh no every everything except when both are one. But

are one. But yeah, no win both are one. And then

BXRC. Let's take this part and BXR C 0 one one one is not. So

zero um zero one one one is not and then we want to knot that

um so let's do everything opposite and we would like to or this part and this All right. So, one

right. So, one um one well everything that's one on the left is one then neither. So, zero and then

neither. So, zero and then one. That should be

one. That should be it.

Yep. Yep.

Okay. And yeah, that's what the working space is meant to be for.

Although, I mean, I suggest you don't do it in your head because just just don't. Okay.

don't. Okay.

This is why [Music] um I said to be careful of this because this is again a boolean not a

character. Number of records we

character. Number of records we have. Okay, I actually have to count.

have. Okay, I actually have to count.

1 2 3 4 5 6 7 8 9 10 11 12 um 15 18. Which field is most suitable for the

18. Which field is most suitable for the primary key? So of course the code would

primary key? So of course the code would be the primary key because the primary key is the identifier the unique one.

Records are row indeed and field is a column but you can easily remember by record row both

are reason is that code code is different for every

record meaning it can distinguish uniquely identify a row from all the other

rows. They like that word so much, you

rows. They like that word so much, you know, unique.

Um breed This can be easier, but I'll just say text just in case, especially with the possibility of

it being on another language. Yes, we

will do the 15 markers. So, hang on tight. Um,

tight. Um, generously because it's M or F age I assume is

integer.

Yep. And arrived is Date. Date

Date. Date time. String is

time. String is wrong. String is not does not exist in

wrong. String is not does not exist in SQL.

only text and alpha numeric remember real does exist.

Yes. But real real are numbers.

Um from what table we can go back to the question and see horses and I assume they want breed origin to be Scotland.

15 marker. Everybody, can we have a round of applause or something?

Thank you. Thank

you. Um, okay. Let's

go. I will I'll just put this on my left screen and then put pseudo code pro on my right screen.

Okay let's see. What does the question

see. What does the question want? Ping. Tenzo. I remember

want? Ping. Tenzo. I remember

Tenzo.

Okay. So, what flooring companies stores names of 100 customers in customers?

quotations shows the details of each customer's um quotation including each. So I

assume by that case the um the index of each row would be the same like the same customer to the same

details of each. The length is one decimal place. The width is one decimal

decimal place. The width is one decimal place. The area is to the whole number.

place. The area is to the whole number.

A choice is whole number. Um and price is whole

number. Um and price is whole number. Measurements are in meters. All

number. Measurements are in meters. All

floors are rectangle. Room measurements are between

rectangle. Room measurements are between 1.5 and five. So that's a range check validation. Remember guys?

validation. Remember guys?

Yeah. and customer in the index 4 um of customers. So yeah, as I said before

customers. So yeah, as I said before um the customer details of the force index was would be in the quotation of index

4 wood choices. These are the ones available and they're in wood type and price.

[Music] Um, they want to input a customer name, the room length and width. Check

that is valid. If not, re-enter until valid. Calculate the area. Input the

valid. Calculate the area. Input the

choice of the wood. Find the price per square meter

wood. Find the price per square meter that is here. So, we have to do a linear search.

Um and calculate or we can use a case off uh calculate the price of the wood needed because now we have the error of the of the room and the price per square

meter. We can just multiply

meter. We can just multiply it store the data in the relevant array and um output the

quotation continue and accept the next customer. This is why you read the whole

customer. This is why you read the whole question first.

um which is because uh you want to this this would be a loop on the whole program and you don't want to rewrite that do you and

since these are already stored values you don't have to declare them but then pseudo code pro very

handy they have this for you if I can find it somewhere

the exam questions. Yes, pass

papers. So you can check for 2023 October November to

[Music] two. No, wrong one. One second.

two. No, wrong one. One second.

[Music] Um, am I tripping? Okay.

tripping? Okay.

Here. Yeah. What's going here?

Okay. This is pseudo code pro.

and yeah. Okay, let's go back.

[Music] Um, so they want us to initialize with type and price that will be no. Okay, let's

be no. Okay, let's first um go through the approach I would take, right? So they want us to initialize. So

right? So they want us to initialize. So

that's definitely what you're going to do initially. And then

initially. And then um since we're going to keep accepting customers, I'll have to make a loop

first to keep accepting customers like a for loop, a while loop, repeat loop, something right?

And then I'll just do inputs. Then a

range check here. Then this means I'll have to use a repeat until um because we want until it's

valid. And then input the wood of

valid. And then input the wood of choice. Um so that's an input and then

choice. Um so that's an input and then that can be done with a case off or that can be done with a linear search preferably a linear

search because uh they gave us an index meaning and they made us make

uh lists uh arrays sorry. So yeah, they definitely want indexing and all that.

Calculate the price of wood needed that can be done by price per square meter and output. So yeah, that's how I would

and output. So yeah, that's how I would approach this question.

So let's declare wood type as an array of uh array as one two three of

um string the names are in string. So yeah

and then the price as a real because it's like this and then We initialize it

one is laminate in pseudo code pro. You could

do like bulk like this laminate and then whatever, but that is not allowed in the

real exams. So, I'll just stick to um what you would do in the exam. And then let's set the price

exam. And then let's set the price $29.99. And I'm just referencing the

$29.99. And I'm just referencing the view.

Now I want to repeat um and let's see if I have to initialize anything before. I don't think so.

before. I don't think so.

Okay, we'll see. Um we want their name and room length and room width.

So room room no other name. Input your

name. Enter.

Um, we can input customer [Music] name of string and

um, you see how I keep like declaring new stuff as I go along. So yeah, as someone pointed out in the chat, you should leave a very large gap at the

start. And so now you can declare stuff

start. And so now you can declare stuff as you go

output enter room length and we want to um keep doing that until it's valid.

So room length is to one decimal place.

So it's a real as a real and then yeah with I'll just say width and length area input

length until um and If the length is we said from 1.5 to 10

inclusive so less than 1.5 or length is um greater than 10. So

this is where it's wrong. Um we want to output an error message.

So invalid boom length would be between 1.5 and 10 inclusive.

Um and if until the length is greater than

equal to 1.5 or length is less than or equal to 10. No. And and

sorry. So now they have to be greater than 1.5 and 10. Uh less than 10. So

they're in between. Now we can do the same thing

between. Now we can do the same thing with the width.

Unfortunately, you do not have copy and paste in the exam. So you will have to type it all out.

And um we will calculate the room area by multiplying times

length. Simple enough.

length. Simple enough.

And then we will input the choice of wood and find

the price per square meter type of wood.

Input. Oh yeah. And in the 15 marker they they want marks for commenting. So

comment as you go along.

initialize types. Just simple stuff like this. even

types. Just simple stuff like this. even

if it's you think it's stupid.

Um, they give Max for it and you probably want Max would type um

uh wood and that's a string they want to enter.

No, we want to find the index. And

index. And [Music] um if they can't find the wood type,

then that mean that means um they entered it wrong. So they have to re-enter. So we'll have to make a

to re-enter. So we'll have to make a loop. and also

loop. and also um check whether it's found they found uh we found the

correct um wood type that they entered.

So we'll make a booty for one two let's say the length of wood type

just so that if we were to use this program in the future um it would be

flexible. Why am I declaring all the

flexible. Why am I declaring all the variables? So,

variables? So, um I I just like to do it. No, I I do it in this case because I'm using Pseudo Code Pro's

website.

Um and it it won't run if I don't declare. Anyways, you should

declare. Anyways, you should uh No, I mean, you can do it if you want. There was a serverwide argument

want. There was a serverwide argument which resulted in like two warnings or something, two timeouts.

Um, the way I like to do it is declare if it's not given. Some people don't declare it at

given. Some people don't declare it at all. Some people declare it

all. Some people declare it um declare everything. Although actually

I didn't identify anything because I use Python. But you shouldn't use Python.

Python. But you shouldn't use Python.

You should use pseudo code because the examiner would be used to marking pseudo code.

[Music] Um now you can let's

find whether the count is the same. So

wood type count is um the same as the wood entered. And if so, first we have to say

entered. And if so, first we have to say found is true.

Then also um also wood index. Yeah, we have to keep track which which one we found which position

actually which is an integer.

which would be the count we're going to. And no, next

to. And no, next count. And then

count. And then um linear search to find index of of wood.

press. Now, we want to do all this until until like they enter wood type that is actually found. This

found. This means we should repeat everything until it's found.

This also means we should uh declare it no we assign found as false post because

[Music] um we haven't no we want it to go into no yeah we want to check whether it's true or false here and the default

should be And we should probably throw in throw a message here saying um if not

found then output in not found what

type and if and this assumes we have found the wood type and kept track of the wood

index. Now we can find the price per

index. Now we can find the price per square meter of that wood price.

[Music] Um, well, yeah, it would just be price of wood type. No, wood

index. But I'll just use this whole thing when we're going to use it. Store data in relevant array. That's

it. Store data in relevant array. That's

where you do it.

[Music] Um, so in the quotations, oh, up to 100. Okay, that's

why 100 customers. But we'll have to use a wow because they might stop. Hey, will

they? No, they won't. Yeah, four. I'm

sorry.

Good. Good spot.

Um and then I'll add this to locationations of customer count.

And um one would be the length of the room

and two would be the width of the room.

Sorry. 3 would

be the area of the room.

Um, four would be the choice of the [Music]

room. No, choice of wood and X. Sorry.

room. No, choice of wood and X. Sorry.

So that's that. And then the price of wood required in dollars. So the price at wood would

index. Okay, we have

index. Okay, we have stored and now we have to output and everything and the price of wood

required. So let's have a total price

required. So let's have a total price here. They want to round in one dec

here. They want to round in one dec decimal place too. So, let's round that before that.

Um, do you need to have another flag for not found? I don't know what you mean.

Cuz if you found Yeah, it will run forever.

But we want them to give us a valid wood type. That's the whole point.

type. That's the whole point.

Well, price of wood required in dollars. That means um we have to

dollars. That means um we have to calculate the final price before do don't we? Okay. Total price. Total

don't we? Okay. Total price. Total

price is price of wood index times the area. Then we can store the total price

area. Then we can store the total price here. But we'll also have to

here. But we'll also have to round that.

And since for future reference, we also want to um round it for the output too, then we should probably round it here rather

than round on the store because we'll round it on the output anyways. Isn't your validation loop

anyways. Isn't your validation loop running forever then? Because found will never be true if it's not found.

Yeah, it it it it will run forever, but you know, we would expect the customer to actually like do it properly. Sorry. Um, so yeah, we got the

properly. Sorry. Um, so yeah, we got the total price in 2DP and now we want to output customer name.

customer name. I put

name. I put uh wood choice.

[Music] Um what what uh here we can comment again. Calculate

total price by uh by multiplying price and

area. Uh, put name, choice, wood choice,

area. Uh, put name, choice, wood choice, and price. And that should be it. Continue

price. And that should be it. Continue

to accept the next customer.

Um oh yeah, next customer account. And hopefully we didn't do

account. And hopefully we didn't do anything wrong. Let's

anything wrong. Let's see. Same name.

see. Same name.

Okay.

Um, I would have hoped that the length

um without proper casing work, but it would not.

Oh yeah, length does not work here. My

bad.

Three. Um, you can't find the length of an array. I will copy the code once it works and it should just

know quotations has not been declared. I thought pseudo code pro

declared. I thought pseudo code pro would do it for me. Let's not die

me. Let's not die here. Or I don't think I clicked it

here. Or I don't think I clicked it properly actually.

[Music] Um yeah, start the code. Um

code. Um Okay, they do not want to work. Oh,

because there's no sort of code. That's

why. Or at least I don't think so. Yeah, all the quotations and stuff.

so. Yeah, all the quotations and stuff.

It's just I'll do it myself then. No worries.

[Music] Um, declare customers as an array of 1 to 100

um of string. Then declare

quotations quotations with an array one to 100 of um no of real. Yeah.

One two five. There might be a type error. I

five. There might be a type error. I

would be so annoyed. Any tips on how to double check

annoyed. Any tips on how to double check your code?

Um, we'll first check if it probably um if it's proper. That

proper. That being Oh, why did pseudo code pro just capitalize everything I did. That's not

cool. Okay, whatever. Um, yeah, check check whether you commented. check all

the syntax first and then um go through the logic. I

mean yeah maybe before you write plan it out write it somewhere um in pencil comments are mandatory.

Yeah AO3 or something like that. Yeah plan it like with pencil just

that. Yeah plan it like with pencil just so you know the structure of the program.

Um, so then when you come back and read everything, it's it's cool enough.

Oops. Okay. Let's say the length is minus one. That shouldn't work. Okay,

minus one. That shouldn't work. Okay,

that's cool. Five.

Yep. Um,

10. Yep. And

then enter the type of wood. So, we have laminate, pine, and oak. Let's say

birch. That should be wrong. Okay.

Laminate wood choice.

Um, okay. Sorry.

And whoever I'm copying this code to, I'm sorry how um everything is full caps. But yeah, that should be it for

caps. But yeah, that should be it for that. Yeah, that's correct. Right. One

that. Yeah, that's correct. Right. One

second. Um 29.99

* 5 * 10, that's 50. Yay.

50. Yay.

Okay, that's how you do the 15 marker.

That concludes the session.

Do we have any other questions?

Let's take questions for like five minutes. It's It's been a while, right?

minutes. It's It's been a while, right?

Wake up, guys. It's done.

They do appear first.

Is that the last question? 25 marks,

guys. questions quick. Oh yeah, I'll send this in the chat.

No questions. The question says after Yeah, I just changed that.

Do we need to initialize every variable?

Um uh yes. I I don't know what you mean

yes. I I don't know what you mean though. There's there's some variables

though. There's there's some variables in the 15 marker that they tell you that this certain variables stores this certain value.

Yeah. Okay. So, you don't have to initialize those. If you have to

initialize those. If you have to initialize a certain variable, for example, uh the amount of football teams in a certain league. So, the question will ask you to

league. So, the question will ask you to input the number of leagues in the football in enter the number of teams in the football league. So, you will need to initialize that. It depends on the

question. Anything else? When is this

question. Anything else? When is this session going to be uploaded? That's a

big one.

Soon.

Um soon. It's It's pretty late for me.

So, either tonight within this hour or or tomorrow morning. That means you should probably subscribe to the channel.

Um, so so you can get updated whether the video is posted or not. Yeah. Yeah.

If he reaches 100 subscribers by tonight, he'll upload it by tomorrow.

Yeah. Yeah. Yeah. Just say that.

With the notification bell. Yeah.

Yep. Any other questions?

Pseudo code chapter 7 chapter eight um SQL boolean one question. Yep. Okay. Someone

has do we need to use for [Music] functions? Go on. Okay. for Python or

functions? Go on. Okay. for Python or pseudo code. Uh in the in paper two, you

pseudo code. Uh in the in paper two, you only have options to use a programming language for the 15 marker. For the rest of the smaller questions, you have to use pseudo code. So you'll have to learn

pseudo code in any case. And even for the 15 marker, most people say that um pseudo code is marked more leniently. So

you should go for that.

Yes, I support that even though I wrote Python, but you should write pseudo code. Um, unless you're like extremely

code. Um, unless you're like extremely skilled in Python and you're too too lazy to learn pseudo code or whatever, but you should already know pseudo code for the questions before. So, yeah,

you'll have to learn it anyways. Yeah,

for functions, the input taken, do we need to enter a number? Um, in in lower marks, most of the time you don't, but I do it anyways. But um you definitely

need to do it in the 15 marker just so the program is like fully proper um because they want proper proper program, proper variable names, proper

identifiers, proper everything in the 15 marker. How many data types are there in

marker. How many data types are there in SQL? Let's

SQL? Let's see. Let's see. Let's see. Let's see.

see. Let's see. Let's see. Let's see.

Let's see.

very beautiful slides I spent very long making.

[Music] Um yeah. Okay. So text alpha numeric

Um yeah. Okay. So text alpha numeric kind of similar characters boolean integer wheel

daytime no string. The string is basically why

string. The string is basically why aren't functions and procedures used for 15 markers? They are. You have to um you

15 markers? They are. You have to um you can and some questions require you to write them. For example, like the

write them. For example, like the specimen paper, there was the hospital monitor procedure.

Use it if you have to reuse some set of code multiple time. But normally if you don't then just don't bother. Yeah.

Yeah. But sometimes the question they explicitly ask you to write a procedure that does like Pokemon. Yeah. Yeah. Um

hospital one send right the slide. The slide.

So there's some animation that you know blocks is true. So that's why I will clean up the slide and then pin it in

the computer science channel.

So yeah, perfect. So the video, the slides, everything should be pinned in the computer science channel either today or tomorrow.

Um, okay. Whoever asked for

okay. Whoever asked for the Fine, I'll paste the pseudo code in here. Wait. In pseudo code, how would

here. Wait. In pseudo code, how would you put an output message for a function parameter? You don't put an output

parameter? You don't put an output message explicitly like I assume you mean to explain that this parameter does this. You you define the parameter

this. You you define the parameter yourself. So you know which parameter

yourself. So you know which parameter works.

Oh, like as you say input number one, input number for a sum function. No, you

when you're calling the function, you input those in the brackets.