Java operators — which two expressions are equivalent for the integer value 16?\n\nCandidates:\n1) 164\n2) 16>>2\n3) 16/2^2\n4) 16>>>2\n\nAssume 32-bit signed ints and Java operator precedence.

Difficulty: Medium

Correct Answer: 2 and 4

Explanation:


Introduction / Context:
This question reinforces the difference between arithmetic, shift, and bitwise XOR operators in Java, and highlights that ^ is XOR, not exponentiation. It asks which proposed expressions evaluate to the same result when applied to the integer 16.



Given Data / Assumptions:

  • All operations are on ints.
  • >> is arithmetic right shift; >>> is logical right shift.
  • ^ performs bitwise XOR, not power.


Concept / Approach:
Right-shifting 16 by 2 gives 16 / 2^2 in the power sense, but since ^ is XOR, writing 16/2^2 is actually (16/2) ^ 2 by precedence, and since 2 ^ 2 == 0, the expression 16/0 is a constant-expression division by zero which is illegal at compile time. Meanwhile, 16 >> 2 and 16 >>> 2 both yield 4 for a nonnegative integer.



Step-by-Step Solution:

Compute 16 >> 2 → 4 (shift right by 2 bits).Compute 16 >>> 2 → 4 (logical right shift; same for nonnegative values).Expression 164 → 64 (not equal to 4).Expression 16/2^2 → invalid (compile-time error due to divide by zero).


Verification / Alternative check:
Evaluating on a REPL confirms both right-shift variants produce 4 for nonnegative inputs. For negative values, >> and >>> differ.



Why Other Options Are Wrong:

  • Pairs involving 1 do not match 4.
  • Pairs involving 3 use an invalid expression; equivalence cannot hold.


Common Pitfalls:
Misreading ^ as exponent; in Java, there is no exponent operator—use Math.pow for powers.



Final Answer:
2 and 4

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