Programming · 4 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 5% of your exam marks.
1D array manipulation with FOR loops appears regularly in Paper 2. 4 to 6 marks.
To read the value at a given position, use the array name followed by the index in square brackets:
OUTPUT Scores[3] // outputs 5 (the third element)
The expression Scores[3] is just a single value (an integer in this case). It can be used anywhere a normal integer can:
TotalSoFar ← Scores[1] + Scores[2]
IF Scores[4] > 0 THEN
OUTPUT "Has a positive score"
ENDIF
To change the value at a given position, assign with ←:
Scores[2] ← 100 // changes the second element from 10 to 100
// Scores is now: [12, 100, 5, 2, 8]
The other elements are untouched.
If the index is 0 or 6 (in our 5-element example), the access is invalid and the program will report an error or behave unpredictably. Always make sure indices stay within 1 ... LENGTH(array).