Sudocode

• Astronomy
• Upper Secondary (Key Stage 4)
• GCSE

Pseudocode

Sudocode

What is this symbol?

What is abstraction?

a) Removing unnecessary data

b) Break down a task to smaller parts

c) Steps taken to complete a task

What is this symbol?

Sudocode

What is this symbol?

Decision

What is abstraction?

a) Removing unnecessary data

b) Break down a task to smaller parts

c) Steps taken to complete a task

What is this symbol? Input/Output

Sudocode

By the end of this lesson you will know what pseudocode is.

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

What is Pseudocode?

Pseudocode is a way of writing out the steps of a program using plain English mixed with simple programming-style structure.

• It is not a real programming language.
• It does not have strict rules.
• Its purpose is to help you plan your code before actually writing it.

Think of pseudocode as writing instructions for a computer in a way humans can easily read and understand.

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

Why Use Pseudocode?

We use pseudocode to:

• Plan our algorithm before coding
• Avoid errors by thinking through the logic
• Describe programs without worrying about syntax
• Communicate ideas to others clearly

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

Pseudocode syntax

Start/End	Algorithm start and end
Input	Data the user enters
Output	Information shown to the user
If/Else	Decision or a condition
Repeat/While	Loop x times or until x meets a condition

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

I do...

Problem:

Ask the user for two numbers and display the larger one.

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

WE DO — Guided Practice

Task: Write pseudocode for a program that:

• asks the user for their age
• checks if the age is 18 or older
• outputs “Adult” if age ≥ 18
• outputs “Child” if age < 18

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

WE DO — Guided Practice

START

    INPUT ________

    IF ________ >= 18 THEN

        OUTPUT "________"

    ELSE

        OUTPUT "________"

END

• age
• age
• Adult
• Child

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

WE DO — Guided Practice

START

    INPUT age

    IF age >= 18 THEN

        OUTPUT "Adult"

    ELSE

        OUTPUT "Child"

END

Which of the following correctly shows a condition in pseudocode?

1. IF
2. REPEAT
3. INPUT
4. START

If their age is 18 what would the system output?

1. Adult
2. Child

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

You do - Independent practice

Task: Write pseudocode for the following problem on your own:

Problem:

• A security system asks the user to enter a 4-digit PIN.
• The PIN must not be "1234" or "4321".
• If the PIN is valid, output "VALID PIN".
• Otherwise, output "INVALID PIN".

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

You do — Independent Practice

_________

______ pin

_____ length of ______ ≠ __    _______

        _______ "INVALID PIN"

    _______ IF ______ = "1234" ______ pin = "4321" THEN

        OUTPUT "_________"

    _________

        ___________ "VALID PIN"

_________

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

You do — Independent Practice

START

INPUT pin

        IF length of pin ≠ 4    THEN

                PRINT "INVALID PIN"

        ELSE IF pin = "1234"  OR  pin = "4321" THEN

                 OUTPUT " INVALID PIN "

        ELSE

                 PRINT "VALID PIN"

END

Sudocode

LO - By the end of this lesson you will know what pseudocode is.

You do — Stretch

The height a student jumps in the high jump needs to be input and validated. The height is entered in centimetres (cm) and must be between 40.0 and 180.0 inclusive.

Write an algorithm to:

• take the height jumped as input

• output "VALID" or "NOT VALID" depending on the height input.