Pseudocode Concepts

What Is Pseudocode?

Pseudocode is a human-readable notation for describing algorithms. It uses structured language (keywords, indentation) without being tied to any specific programming language. The goal is clarity, not executability.

KEY TAKEAWAY: Pseudocode is the primary language for expressing algorithms in VCE Algorithmics. It bridges natural language and code — precise enough to implement, readable enough for humans.

1. Variables and Assignment

Variables store data values. Assignment uses the ← arrow.

x ← 5
name ← "Alice"
result ← x * 2 + 1

Declaration is implicit — variables are created when first assigned.

2. Sequence

Instructions execute in order from top to bottom.

a ← 3
b ← 4
c ← a + b     // c = 7

3. Conditionals

Branch based on a Boolean condition.

if condition then
    // executed if condition is true
else if other_condition then
    // executed if other_condition is true
else
    // executed if no condition is true
end if

Example:

if score >= 50 then
    result ← "pass"
else
    result ← "fail"
end if

4. Iteration (Loops)

For Loop — iterate a fixed number of times

for i ← start to end do
    // body executed for each value of i
end for

For-Each Loop — iterate over a collection

for each item in collection do
    // body
end for

While Loop — iterate while a condition holds

while condition do
    // body
end while

Example — sum of first n integers:

sum ← 0
for i ← 1 to n do
    sum ← sum + i
end for
return sum

5. Functions

Functions encapsulate reusable logic with inputs (parameters) and an output (return value).

FUNCTION functionName(param1, param2)
    // body
    return result

Example:

FUNCTION isEven(n)
    if n mod 2 = 0 then
        return true
    else
        return false
    end if

Calling a function:

result ← isEven(6)   // result = true

6. Logical Operations in Conditions

Pseudocode Style Guidelines (VCAA)

• Use ← for assignment (not =)
• Use = for equality comparison
• Indent loop and conditional bodies consistently
• Use descriptive variable names
• Comments with //
• ADT operations: Stack.push(S, x) or push(S, x)

EXAM TIP: When writing pseudocode in exams, use consistent notation. Marks are awarded for logical correctness and clarity, not for syntax — but you must be unambiguous.

Complete Example: Linear Search

ALGORITHM LinearSearch(A, target)
    for i ← 0 to length(A) - 1 do
        if A[i] = target then
            return i
        end if
    end for
    return -1