ITPEC FE Subject B April 2026 Question 7

A is Index and B is index - 1.

The recursion scans the array from the last position down to the first:

• •linearSearch starts it with index = N
• •index < 1 means the whole array has been examined without a hit, so -1 is returned
• •if D[index] equals the key, the position wanted is the current index itself — that is blank A
• •otherwise the search must continue one position to the left, so the recursive call passes index - 1 — that is blank B

Answer (d)

Why not others:
- (a), (b) and (c) — return the constant 1 on a hit, reporting the first position no matter where the value was found
- (g), (h) and (i) — return index - 1, one position to the left of the element that actually matched
- (e) and (h) — recurse with N - 1, a value that never changes between calls, so the recursion never reaches the base case
- (f) and (i) — recurse with N - index, which jumps around the array instead of stepping through it

Key rule: In a recursive scan the parameter must move steadily toward the base case. Anything built from N alone is constant across calls and loops forever.

AI-generated — may contain errors