Computer Science · May / June 2023 · Paper 21 · Question 5
0478
As printed in the paper
The question as text
An algorithm has been written in pseudocode to allow some numbers to be input. All the positive numbers that are input are totalled and this total is output at the end. An input of 0 stops the algorithm. 01 Exit ← 1 02 WHILE Exit <> 0 DO 03 INPUT Number 04 IF Number < 0 05 THEN 06 Total ← Total + Number 07 ELSE 08 IF Number = 0 09 THEN 10 Exit ← 1 11 ENDIF 12 ENDIF 13 ENDIF 14 OUTPUT "The total value of your numbers is ", Number
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Show the answer and mark scheme
5(a)[4]
One mark per mark point, max four
Line 04 / IF Number < 0should be IF Number > 0
Line 10 / Exit ← 1 // Line 01/ Exit ← 1 and Line 02 / WHILE Exit <> 0should be Exit ← 0 // should be Exit ← 0 and WHILE Exit = 0
Line 13 / ENDIFshould be ENDWHILE
Line 14 / OUTPUT "The total value of your numbers is ", Numbershould be OUTPUT "The total value of your numbers is ", Total
Correct algorithm:
01 Exit ← 1
02 WHILE Exit <> 0 DO
03 INPUT Number
04 IF Number > 0
05 THEN
06 Total ← Total + Number
07 ELSE
08 IF Number = 0
09 THEN
10 Exit ← 0
11 ENDIF
12 ENDIF
13 ENDWHILE
14 OUTPUT "The total value of your numbers is ", Total
5(b)[4]
One mark per mark point, max four
Initialise a new (counting) variable… Count ← 0 // to count the acceptable numbersInsert a counting statement between lines 05 and 07… Count ← Count + 1Add a new output after the loop/after line 13 / at the end (of the program)… OUTPUT Count
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