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Practice · 2 of 4

Parameter passing trace

CHALLENGE
Difficulty: intermediate+25 XP

Trace run(5) by hand: shift doubles its parameter and returns v - 1, but the first call's result is **discarded**. Predict run(5), then implement run so the tests pass — the buggy instinct is to think the discarded call changed v.

Back to lesson: Practice: Tracing lab