C switch-case constants and duplicates: Which compilation error(s) will be reported for this switch that includes a computed case and a literal with the same value? #include <stdio.h> int main() { int a = 5; switch (a) { case 1: printf("First"); case 2: printf("Second"); case 3 + 2: printf("Third"); case 5: printf("Final"); break; } return 0; }

Introduction / Context:
This question focuses on constant expressions in case labels and the prohibition of duplicate case values. It also checks the misconception that every case must end with a break to compile.

Given Data / Assumptions:

• A case uses 3 + 2.
• Another case uses the literal 5.
• Several cases have no break.

Concept / Approach:
Case labels must be integer constant expressions, and duplicates are illegal. The expression 3 + 2 is a constant expression that evaluates to 5 at compile time, colliding with the later case 5:. Missing break may cause fall-through, but that is a runtime behavior choice, not a compile error.

Step-by-Step Solution:
Evaluate 3 + 2 → 5.Detect duplicate labels: case 3 + 2 and case 5 both equal 5.Compiler emits duplicate case label error.

Verification / Alternative check:
Replace one of the labels with a distinct constant (e.g., 6) and compilation succeeds, regardless of missing break statements.

Why Other Options Are Wrong:
Expression not allowed — constant expressions are allowed. No break in each case — not a compile error. No error — incorrect due to duplication.

Common Pitfalls:
Forgetting that constant expressions are folded at compile time; believing break is mandatory.

Final Answer:
Duplicate case case 5: