Explain why constants, variables and arrays are used in programming. Constants Variables Arrays

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.

1. [6] Constants
2. Two from:
3. ∞ The value cannot be changed accidentally ...
4. ∞ ... during the execution of the program
5. ∞ Value only needs to be changed once if circumstances change/during the initialisation process
6. Variables
7. Two from:
8. ∞ Stores a value that can change ...
9. ∞ ... during the execution of the program
10. ∞ Can use a variable without knowing its value
11. Arrays
12. Two from:
13. ∞ A list of items of the same data type ...
14. ∞ ... stored under a single name
15. ∞ To reduce the number of variables used
16. ∞ Any item can be found using an index number to show its place in the list