A procedure TwoParts() will input a sequence of real values, one at a time. The procedure will: • process the sequence in two parts • form a first total by adding the values until the first zero • form a second total by adding the values after the first zero until the second zero • output the average of the two totals, together with a suitable message. Values input in the first part are totalled using global variable TotalA and those input in the second part are totalled using global variable TotalB.

Mark scheme

Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.

1. [1] (a) Procedure heading and ending
2. [1] (a) Declare all local variables
3. [1] (a) Initialise TotalA and TotalB
4. [1] (a) First conditional loop until zero entered, summing TotalA // Loop until both parts (sequences) have been entered
5. [1] (a) Second conditional loop until zero entered, summing TotalB // Loop summing appropriate Totals
6. [1] (a) Calculation of average and output with a message // Calculation of the average for the values making up the two totals and both output with a suitable message
7. [1] (b)(i) (1D) array
8. [1] (b)(i) of 20 reals
9. [1] (b)(ii) (Multiple instances referenced via a single identifier so) fewer identifiers needed
10. [1] (b)(ii) Easier to process / search / organise / access the data // Values may be accessed via a loop-controlled variable /an index //An array / data can be iterated through
11. [1] (b)(ii) Makes the program/algorithm easier to write / design / understand / maintain / modify // Simplifies the program // Easier to debug / test