Difficulty: Easy
Correct Answer: 43
Explanation:
Introduction / Context:
This snippet chains parsing, formatting, and rounding. The key is understanding that Math.ceil rounds up to the nearest integer (as a double) and that casting to int then truncates toward zero, preserving the rounded integer value in this case.
Given Data / Assumptions:
s = "42", then s.concat(".5") → "42.5".Double.parseDouble("42.5") succeeds, producing 42.5.Math.ceil(42.5) = 43.0.
Concept / Approach:
Double.valueOf(s).doubleValue() is redundant after parsing, but it returns the same double. Math.ceil returns a double whose value is the smallest integer greater than or equal to the argument. Casting this value to int simply yields that integer.
Step-by-Step Solution:
Verification / Alternative check:
Had the code used Math.floor, the result would be 42. Using Math.round(42.5) would yield 43 as well (ties go to +∞ for positive halves in Java’s round-to-nearest-even? Actually, round(42.5) = 43 in Java).
Why Other Options Are Wrong:
ceil and integer casting.Double.
Common Pitfalls:
Expecting a NumberFormatException from "42.5"; that would occur for Integer.parseInt, not Double.parseDouble.
Final Answer:
43
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