GCSE Computer Science (8525/2) – Paper 2:
Computing Concepts
Practice Exam Paper | Time allowed: 1 hour 30 minutes
Total marks: 80
Instructions:
• Answer all questions.• You must write your answers in the spaces provided.• You may use a calculator.
Section A – Algorithms and Programming (42 marks)
Question 1: Algorithms (8 marks)
The following pseudocode is intended to calculate the average of five test scores entered by the user.total = 0 count = 0
REPEAT 5 TIMES
INPUT score total = score count = count + 1 average = total / count OUTPUT average
a) Identify one logic error in the pseudocode. (2 marks)
Answer:
The line total = score should be total = total + score. (1 mark for identifying incorrect line, 1 mark for correct fix)
b) Rewrite the corrected pseudocode. (3 marks)
Answer:
total = 0 count = 0
REPEAT 5 TIMES
INPUT score total = total + score count = count + 1 average = total / count OUTPUT average 1 / 2
(1 mark for correct initialization, 1 mark for corrected accumulation, 1 mark for correct average)
c) What is the purpose of the variable count in the pseudocode? (1 mark)
Answer:
It keeps track of how many scores have been entered.
d) State one reason why a FOR loop would be better than a REPEAT loop in this situation.
(2 marks)
Answer:
Because the number of repetitions (5) is known in advance. (1 mark for stating FOR loop is more appropriate, 1 mark for reason)
Question 2: Trace Tables (6 marks)
Given the pseudocode:
x = 3 y = 2 WHILE x < 10 y = y + 1 x = x + y OUTPUT x, y Complete the trace table.Iteration x y Start 3 2
- 5 3
- 9 4
3 14 5
(1 mark per correct row after "Start" = 3 marks)
Final Output: 14 5 (1 mark)
Explanation: (2 marks – 1 for tracking x, 1 for tracking y correctly)
Question 3: Subroutines and Parameters (6 marks)
a) Explain the difference between a function and a procedure. (2 marks)
Answer:
A function returns a value; a procedure does not. (1 mark each point)
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