Introduction

Paper 4 is the practical programming paper in Cambridge International A Level Computer Science (9618). Unlike Papers 1, 2 and 3 — which are written exams — Paper 4 requires you to write and run actual programs on a computer.

• It tests your ability to write working programs, not just talk about them.
• Every syllabus topic — OOP, ADTs, file handling, algorithms — is tested through code you write, run and screenshot.
• OOP and ADTs are core skills, not optional extras.

Paper 4 differs from Paper 3 in one important way: Paper 3 tests whether you understand concepts; Paper 4 tests whether you can actually implement them.

From many years of past papers, you should always expect these three question types:

Cambridge Paper 4 examiners are not looking for the cleverest solution. They are looking for code that is readable, correct, and traceable. A simple 20-line solution that works scores more than a clever 5-line solution that is hard to follow.

Python is one of the approved languages for Cambridge 9618 Paper 4 (alongside Java and Visual Basic .NET). Python is used throughout this site because it is clear, readable, and its structure maps closely to Cambridge pseudocode.

Safe features vs features to avoid

Cambridge Paper 4 questions often provide pseudocode describing the algorithm. Your Python must follow the same logic order, use similar variable names, and implement each step clearly. Do not restructure the algorithm unless asked.

DECLARE total : INTEGER
total <- 0
FOR i <- 1 TO 5
  OUTPUT "Enter score: "
  INPUT score
  total <- total + score
NEXT i
OUTPUT "Total: ", total

total = 0
for i in range(1, 6):
    score = int(input("Enter score: "))
    total = total + score
print("Total:", total)

CLASS Animal
  PRIVATE name : STRING
  PRIVATE sound : STRING

  PUBLIC PROCEDURE NEW(n, s)
    name <- n
    sound <- s
  ENDPROCEDURE

  PUBLIC FUNCTION makeSound() RETURNS STRING
    RETURN name & " says " & sound
  ENDFUNCTION
ENDCLASS

class Animal:
    def __init__(self, n, s):
        self.__name = n
        self.__sound = s

    def makeSound(self):
        return self.__name + " says " + self.__sound

a = Animal("Cat", "meow")
print(a.makeSound())

Quick pseudocode → Python reference

Fifteen exam-style tasks. Click Hint for bullet-point guidance, then Help to reveal a worked Python solution.