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A-Level Computer Science Past Papers & Drilling (Paper 4): Program Design, Testing
TUTORZONE ORIGINAL DRILLING MOCK · CAMBRIDGE A-LEVEL COMPUTER SCIENCE (9618) PAPER 4
Written to the Cambridge 9618 syllabus (2027-2029): Paper 4 Practical, 75 marks, 2 h 30 min (sections 19-20; submit program code and testing evidence in Java, VB or Python console mode). Also Paper 1 theory (75), Paper 2 programming (75) and Paper 3 advanced theory (75). This is a Paper 4 drilling mock: 4 questions for 75 marks with answers and techniques.
What is in A-Level Computer Science (9618) Paper 4?
Direct answer: Paper 4 Practical, 75 marks, 2 h 30 min, submitting program code and testing evidence (Java/VB/Python console).
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 4 (Practical) | Submit code + testing, 75 marks | 25% A-Level | 2 h 30 min |
| Paper 2 (Problem-solving and Programming) | Answered in pseudocode, 75 marks | 25% A-Level | 2 hours |
A-Level Computer Science Paper 4 drilling technique: write the design (input-process-output) before coding; arrays are 0-based (0 TO 3); write boundary-value tests for functions; print your test evidence before submitting. Boundary testing is a common lost mark.
How this paper was built
This is a TutorZone original drilling mock: the questions follow the Cambridge 9618 structure (Paper 4, 75 marks) and the answers are our own, not Cambridge past papers or marking references.
Numeric and trace answers were recomputed programmatically.
Pacing
| Section | Marks | Suggested time | What to do first |
|---|---|---|---|
| Paper 4 (Practical) | 25% A-Level | 20 min plan, 100 min code, 30 min test | design + code + test |
| Paper 2 (Problem-solving and Programming) | 25% A-Level | about 20 min per question | algorithms + data structures |
Why does boundary-value testing matter?
Direct answer: boundary values (79/80) expose condition errors and are a common lost mark.
Paper 4: practical drilling (4 questions, 75 marks)
Design before coding; boundary-test your functions.
Question 1 (20 marks)
Write a program design that reads four marks [72, 85, 63, 90] and computes the average.
Question 2 (15 marks)
Write code to find the highest mark and output it.
Question 3 (20 marks)
Write a function returning a grade from the average (77.5): >=80 ‘A’, >=70 ‘B’, otherwise ‘C’.
Question 4 (20 marks)
Write a test plan for the Grade function at boundaries 79, 80, 69, 70. What are the expected results?
What matters in the grade function’s condition order?
Direct answer: test the higher threshold first (>=80 before >=70), or the top grade can never be returned.
Paper 4 answers
Question 1
marks <- [72, 85, 63, 90] -> 77.5 (20).
total <- 0
FOR i <- 0 TO 3
total <- total + marks[i]
NEXT i
average <- total / 4
OUTPUT average
Question 2
highest <- marks[0] -> 90 (15).
FOR i <- 1 TO 3
IF marks[i] > highest THEN
highest <- marks[i]
ENDIF
NEXT i
OUTPUT highest
Question 3
FUNCTION Grade(avg) -> ‘B’ (20).
IF avg >= 80 THEN RETURN 'A'
ELSEIF avg >= 70 THEN RETURN 'B'
ELSE RETURN 'C'
ENDIF
ENDFUNCTION
Question 4
79 -> ‘B’; 80 -> ‘A’; 69 -> ‘C’; 70 -> ‘B’ (5 each). The test plan should list input, expected and actual output.
Which topics does this paper drill?
Direct answer: program design, array processing, functions and boundary-value test plans.
Where these marks are usually lost
| Mistake | What it looks like | What it costs | Instead |
|---|---|---|---|
| No test plan | Code only | List input, expected and actual output | test evidence |
| Array bound wrong | 1 TO 4 | 0-based: 0 TO 3 | 0 TO 3 |
| Condition order wrong | >=70 before >=80 | Test the higher threshold first | >=80 first |
How to use this paper
First drill: the full 2 h 30 min on all 4 questions with no references.
Mark it: check the boundary values and test plan.
Second drill: redo three to seven days later, aiming to finish inside 2 h 10 min.
What should I do after drilling this paper?
Direct answer: log answers with no test plan or wrong array bounds; redo in three to seven days; and drill Paper 2 programming.
FAQ
Is this a Cambridge past paper?
No. The questions and answers are TutorZone originals, not Cambridge past papers or marking references.
What is in A-Level Computer Science Paper 4?
Practical: submit complete program code and testing evidence, 75 marks, 2 h 30 min, in Java, VB or Python console mode.
Why does boundary-value testing matter?
Boundary values (79/80) expose condition errors and are a common lost mark.
Official references
| Resource | What to check |
|---|---|
| Cambridge A-Level Computer Science 9618 syllabus (2027-2029) | Confirm the Paper 1-4 marks and times |
| https://www.tutorzone.com.hk/en-alevel-computer-science-9618-paper-2-mock-2027/ | A-Level Computer Science Paper 2 drilling mock |
Related: practice area · A-Level Computer Science Paper 2 drilling mock
Next step: find a tutor / register as a tutor
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