Writing Exam-Style Programs

The programming spec is taught topic by topic — variables, then selection, then iteration, then arrays, then subroutines. But Paper 1 exam questions do not arrive topic by topic. A question might ask you to write a program that uses all of those things together, in a single coherent solution.

This lesson does not introduce new programming concepts. It shows you how to pull everything you already know into a complete program — the way the exam requires you to.

The biggest Paper 1 mistake is writing code immediately. Students who plan first write cleaner, more complete programs and make fewer errors.

Always start with inputs, processing, outputs (IPO):

Scenario: Write a program that asks a user to enter 5 quiz scores (each between 0 and 10), validates each score, stores them, calculates the average, and tells the user whether they passed (average ≥ 6) or failed.

Component	Detail
Inputs	5 quiz scores, each entered by the user
Processing	Validate each score (range 0–10); store in array; sum all scores; calculate average
Output	Each invalid score rejected with a message; final average; "Pass" or "Fail"

What programming constructs do I need?

• Array to store 5 scores
• FOR loop to collect 5 inputs
• WHILE loop (inside FOR) for validation
• Accumulator to total the scores
• IF/ELSE for pass/fail decision
• FUNCTION to keep validation reusable

Planning this before writing means you will not reach the end and realise you forgot validation, or used the wrong loop type.

With the plan in hand, build the solution piece by piece.

Pseudocode:

FUNCTION getValidScore()
    OUTPUT "Enter score (0-10): "
    score ← INT(USERINPUT)
    WHILE score < 0 OR score > 10 DO
        OUTPUT "Invalid. Enter a score between 0 and 10: "
        score ← INT(USERINPUT)
    ENDWHILE
    RETURN score
ENDFUNCTION

SUBROUTINE runQuiz()
    scores ← [0, 0, 0, 0, 0]
    total ← 0

    FOR i ← 0 TO 4
        scores[i] ← getValidScore()
        total ← total + scores[i]
    NEXT i

    average ← total / 5

    OUTPUT "Your average score is: " & STR(average)

    IF average ≥ 6 THEN
        OUTPUT "Pass"
    ELSE
        OUTPUT "Fail"
    ENDIF
ENDSUBROUTINE

runQuiz()

Python equivalent:

def get_valid_score():
    score = int(input("Enter score (0-10): "))
    while score < 0 or score > 10:
        print("Invalid. Enter a score between 0 and 10.")
        score = int(input("Enter score (0-10): "))
    return score

def run_quiz():
    scores = [0] * 5
    total = 0

    for i in range(5):
        scores[i] = get_valid_score()
        total += scores[i]

    average = total / 5
    print(f"Your average score is: {average}")

    if average >= 6:
        print("Pass")
    else:
        print("Fail")

run_quiz()

Once written, verify the program with a trace table. Use a test case that exercises the validation (an invalid input followed by a valid one) and checks the pass/fail branch.

Test: inputs are 10, 8, 7, 6, 9 — all valid, average = 8.0, expect Pass.

i	score entered	valid?	scores[i]	total after
0	10	✓	10	10
1	8	✓	8	18
2	7	✓	7	25
3	6	✓	6	31
4	9	✓	9	40

average = 40 / 5 = 8.0 → 8.0 ≥ 6 → Output: "Pass" ✓

Test: one invalid input — user enters 15, then 8.

Attempt	Input	Condition: 15 < 0 OR 15 > 10	Action
1	15	TRUE	Reject, ask again
2	8	FALSE	Accept, exit WHILE

score returned = 8 ✓

These errors appear in student answers repeatedly. Check your program against every item before you stop writing.

1. Uninitialised variables

# Wrong — total has no starting value
FOR i ← 0 TO 4
    total ← total + scores[i]
NEXT i

# Correct
total ← 0
FOR i ← 0 TO 4
    total ← total + scores[i]
NEXT i

Using a variable before assigning it a value is a logic error that produces unpredictable results.

2. Missing ENDIF or ENDWHILE

# Wrong
IF average ≥ 6 THEN
    OUTPUT "Pass"
ELSE
    OUTPUT "Fail"
# Missing ENDIF — syntax error, program cannot run

Every IF needs ENDIF. Every WHILE needs ENDWHILE. Every FOR needs NEXT. Check these before finishing.

3. Wrong loop type

• FOR — use when you know the exact number of iterations in advance (e.g. "collect 5 scores")
• WHILE — use when you repeat until a condition changes (e.g. "keep asking until valid")

Using a FOR loop for validation forces a fixed number of attempts. Using a WHILE loop to collect exactly 5 scores makes the count harder to control. Match the loop type to the problem.

4. Array index errors

AQA pseudocode arrays are zero-indexed by convention in most contexts. A 5-element array uses indices 0 to 4. A FOR loop to fill it should run FOR i ← 0 TO 4, not 1 TO 5.

5. No validation on user input

If the question describes a range or constraint on input, validate it. An unvalidated input that accepts any value — including impossible ones — is an incomplete answer for any question that asks for a "robust" or "secure" program.

6. Using SUBROUTINE when a value needs to be returned

A SUBROUTINE performs actions but does not return a value. A FUNCTION calculates and returns a value with RETURN. If your code needs to use the result of a called block elsewhere, it must be a FUNCTION.

# Wrong — SUBROUTINE cannot be used to return a value
SUBROUTINE getValidScore()
    ...
    RETURN score   # invalid in a SUBROUTINE
ENDSUBROUTINE

# Correct
FUNCTION getValidScore()
    ...
    RETURN score
ENDFUNCTION

7. Vague identifier names

x, a, temp tell the examiner nothing. Use names that reflect the variable's purpose: score, total, average, userName. Clear identifiers also reduce your own mistakes.

The program in this lesson follows a pattern you can adapt to almost any Paper 1 question:

1. Define a FUNCTION to get and validate a single piece of input
2. Use a FOR loop to collect the required number of inputs into an array
3. Process the array (total, count, find max/min, search, sort)
4. Output results using IF/ELSE or OUTPUT statements
5. Wrap in a SUBROUTINE called at the end

Not every question needs every component. But thinking in this structure before writing means you will not forget validation, will not use the wrong loop, and will not miss an ENDIF.