ITPEC IP April 2026 Question 6
ITPEC IP April 2026 — Question 6 of 100
Save A in TMP, copy B to A, then copy TMP to B — the temporary variable preserves the value that the first assignment would otherwise destroy.
Let the original values be A = x and B = y. The sequence in option (b) gives:
- •
TMP ← A, so TMP holds x - •
A ← B, so A becomes y - •
B ← TMP, so B becomes x
The final values are therefore exchanged.
Answer (b)
Why not others:
- (a) finishes with B ← A after A already became y, leaving both variables equal to y
- (c) saves B, then overwrites A with B and restores B from TMP; both remain y
- (d) overwrites A and then copies that overwritten value to B, again leaving both equal to y
Key rule: Before overwriting one swap operand, save its original value; the final assignment must restore that saved value into the other operand.
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