Pseudocode 📝 - Digital Solutions 2025

Pseudocode is a simplified way of writing out the steps of an algorithm without worrying about the rules of a specific programming language.

It helps programmers:

plan before coding
spot errors more easily
explain logic to others
write readable documentation
transition smoothly from idea to code

Key advantages:

Easier to read than real code
Faster to write and update
Good for testing logic before coding
Helps with collaboration between tech and non-tech team members
Ideal bridge between flowcharts and final code

QCAA Pseudocode Rules¶

In Digital Solutions, pseudocode is the standard way to represent algorithms. Since schools use different programming languages, the syllabus uses pseudocode to ensure consistency. The QCAA has set specific rules for how it must be written.

Keywords¶

KEYWORDS should be written bold and capitalized.

Keywords do not have to be valid programming language words as long as they clearly convey the intent of the line of pseudocode.

Calculations¶

Pseudocode should clearly indicate what is happening at each step, including formulas of calculations.

For example: CALCULATE net is not as clear as CALCULATE net = gross − tax

Naming Conventions¶

Use snake case naming convention for variable names with multiple words, subroutines, methods and functions.

Snake case is a convention where all words are in lowercase and spaces between words is replaces with an _

For example: VAR file_name

Font¶

Use a mono-space typeface when writing algorithms on computer:

Windows mono-space fonts:

Courier New
Consolas
Cascadia Code
Cascadia Mono

Mac mono-spaced fonts:

Andalé Mono
Consolas
Courier
Courier New

Variables¶

To input or output values, common words can be used as keywords.

For example:

INPUT mark
WRITE "the total is" count
PRINT x, y
DISPLAY name, result
READ name from list.txt
OUTPUT average

Pseudocode uses the assignment operator, = to assign values.

For example:

CALCULATE net = gross - tax

Simple Pseudocode Activities

Activity 1 Create an algorithm that asks the user to enter the length and width of a rectangle, calculates the area, and displays the result.

Activity 2 Create an algorithm that asks the user to enter the number of hours worked and the hourly rate, calculates the total pay, and displays the result.

Activity 3 Create an algorithm that reads three student marks from a file called marks.txt, calculates the average, and writes the result to a file named average.txt.

Modularisation¶

All pseudocode modules start and ends with the BEGIN and END keywords.

Main algorithm:

BEGIN
    statements
END

Defining procedures, subroutines, methods or functions

BEGIN function_name
    statements
END

Calling procedures, subroutines, methods or functions

statements
function_name
statements

Modularisation Pseudocode Activities

Activity 1 Create a program that calculates the perimeter of a rectangle. The main program should:

Ask the user to input the length and width
Call a module named calculate_perimeter which returns the perimeter using the formula: perimeter = 2 × (length + width)
Display the result to the user

Activity 2 You are designing a program that reads a student’s name and score from a file called input.txt. The main program should:

Call a function named generate_report
generate_report should call another function named format_score, which returns a sentence combining the name and score
generate_report should write that sentence to a file called report.txt

Iterations¶

There are three main types of loops — each has a clear start and end, with the statements within the loop indented.

Post-test loops

REPEAT
    statements
UNTIL condition

Pre-test loop

WHILE condition
    statements
ENDWHILE

Counted loop

FOR count = start_val TO end_val
    statements
NEXT count
ENDFOR

Iteration Pseudocode Activities

Activity 1 Write an algorithm that displays the numbers 1 to 10, one per line.

Activity 2

Write an algorithm that asks the user to enter a password. Repeat until the correct password "admin123" is entered.

Activity 3

Write an algorithm that displays a menu with options and asks the user for a choice. Keep repeating until the user enters "exit".

Activity 4

Write an algorithm that reads 5 numbers from the user and calculates the total.

Selection¶

A control structure used for decisions or branching and choosing alternate paths. The beginning and end of these structures are indicated with keywords.

IF statement

IF condition THEN
    statements
ENDIF

IF...ELSE statement

IF condition THEN
    statements
ELSE
    statements
ENDIF

IF...ELIF...ELSE statement

IF condition THEN
    statements
ELSE IF condition THEN
    statements
ELSE
    statements
ENDIF

MATCH statement

In most other languages these are called switches

SWITCH test_variable
    CASE option
        statements
    CASE option
        statements
    CASE option
        statements
ENDSWITCH

Selection Pseudocode Activities

Activity 1

Ask the user for a number. If the number is greater than 100, display "Big number".

Activity 2

Ask the user to enter their age. If the age is 18 or over, display "Adult", otherwise display "Minor".

Activity 3

Ask the user to enter a test score (0–100).

If the score is 80 or more, display "High"
If the score is 50 or more, display "Medium"
Otherwise, display "Low"

Activity 4

Ask the user to type a day abbreviation (eg. "mon", "tue", "wed"). Display the full day name (e.g. "Monday").

SQL¶

The QCAA does not have any opinion about the pseudocode for SQL. Therefore, just write your SQL code like you would use it in your program.

Full Pseudocode Activities

Activity 1 You are creating a program to process student results. The program should:

Read a list of 5 student names and their scores from scores.txt
For each student:
- Calculate if their score is a pass or fail (pass mark is 50)
- Store a formatted message like “Jamal scored 78: PASS”
Write all results to a file called results.txt
Repeat this process until the file is finished
Use modularisation to separate the calculation logic from the report generation

Activity 2 You’re building a system for a group of friends who ordered multiple pizzas and want to split the cost based on how many slices each person ate.

Each line in pizza_log.txt contains: person_name, slices_eaten

The total cost and total number of slices are entered by the user.

The program should:

Ask the user for the total pizza cost and the total number of slices across all pizzas.
For each line in pizza_log.txt, read the person’s name and slices eaten.
Use a function called calculate_share to calculate what that person owes.
Write each person’s name and amount owed to pizza_bill.txt.
Accumulate the total collected and display it at the end.

What Pseudocode to Include¶

Your assignment have limited space, so you will not be able include all your algorithms as pseudocode. That presents the question, what code should you include?

Ultimately, the pseudocode presented in your assignment should demonstrate your coding skill. Choose the algorithms that you are most proud of, or that you found the trickiest.

Also keep in find that you should be demonstrating all six of the algorithm basic building blocks:

sequence
assignment
conditions
selection
iteration
modularisation

General Pseudocode Activities

What are two key advantages of writing pseudocode before coding?
Why does the QCAA use pseudocode instead of specific programming languages?
What naming convention should be used for variables and functions in pseudocode?
What pseudocode should you include in your assignments?
What are the six basic building blocks that should be demonstrated in your pseudocode?