Question Constellation Sign up for free AQA · GCSE · Computer Science · Higher
Inputs producing Unknown output
Figure 2 shows an algorithm, represented using pseudo-code. Line numbers are included but are not part of the algorithm.
| 1 | num ← USERINPUT |
| 2 | IF NOT(num > 1) OR num > 20 THEN |
| 3 | OUTPUT "False" |
| 4 | ELSEIF num > 1 AND num < 15 THEN |
| 5 | OUTPUT "Almost" |
| 6 | ELSEIF num MOD 5 = 0 THEN |
| 7 | OUTPUT "True" |
| 8 | ELSE |
| 9 | OUTPUT "Unknown" |
| 10 | ENDIF |
A user inputs a value into the algorithm in Figure 2. State one value that the user could input that would result in an output of Unknown.
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Marking points
- 1 States at least one valid Unknown-producing input: 16, 17, 18 or 19, with no incorrect value.
Full-mark answer
16
Why this answer loses marks
Any value inside the broad allowed range.
This does not trace the earlier conditions, so the proposed value could be caught by a different output branch first.