Difficulty: Medium
Correct Answer: same results 2 time(s)
Explanation:
Introduction / Context:
This problem compares two rounding-style expressions across an array of doubles: rounding x + 0.5 using Math.round, and taking Math.ceil of x. You must evaluate each element carefully, considering IEEE rounding rules, negative numbers, and boundary behavior.
Given Data / Assumptions:
Concept / Approach:
Work element by element, converting Math.round’s result to a long and Math.ceil’s result to a double; the == comparison promotes long to double for equality testing. Focus on how negative values behave with rounding and ceiling.
Step-by-Step Solution:
v = -2.3 → v + 0.5 = -1.8 → round(-1.8) = -2; ceil(-2.3) = -2 → equal (count++). v = -1.0 → v + 0.5 = -0.5 → round(-0.5) = 0; ceil(-1.0) = -1 → not equal. v = 0.25 → v + 0.5 = 0.75 → round(0.75) = 1; ceil(0.25) = 1 → equal (count++). v = 4.0 → v + 0.5 = 4.5 → round(4.5) = 5; ceil(4.0) = 4 → not equal. Total count = 2.
Verification / Alternative check:
Try v = 1.2 (round 1.7 = 2, ceil 1.2 = 2) to see another equality case; explore edge cases like v = -0.1.
Why Other Options Are Wrong:
0/1/4 miscount the matches; the code compiles fine.
Common Pitfalls:
Misunderstanding rounding with negatives; forgetting that round(4.5) becomes 5.
Final Answer:
same results 2 time(s)
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