Question Constellation Sign up for free AQA · GCSE · Computer Science · Higher
Rewriting a condition without NOT
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 |
Rewrite line 2 from the algorithm in Figure 2 without using the NOT operator. The algorithm must still have the same functionality.
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Marking points
- 1 Replaces NOT(num > 1) with an equivalent boundary test that includes 1, while retaining OR num > 20.
Full-mark answer
IF num ≤ 1 OR num > 20 THEN
Why this answer loses marks
I removed NOT but changed the connector between the two tests as well.
Only the negated comparison should be inverted; changing the connector changes which inputs reach the branch.