C++ Handbook

`case` — C Keyword

`case` — C Keyword

The case keyword in C: defines a labeled branch within a switch statement.

How to use this reference page

Use reference pages to confirm names, categories, nearby facilities, and the constraints that matter before writing or reviewing code.

  • Scan the top of the page first to identify the primary types, functions, or algorithm families involved.
  • Use the nearby-page links when your question is really about a companion header, related algorithm family, or broader subsystem.
  • Validate tricky behavior with a small compileable example before relying on memory for details like invalidation, ordering, allocation, or lifetime rules.

case (C)

Defines a labeled branch within a switch statement. Execution jumps to the first matching case.

Syntax

switch (expr) {
    case constant: statements
}

Example

#include <stdio.h>

int main(void) {
    char c = 'a';

    switch (c) {
        case 'a': case 'e': case 'i':
        case 'o': case 'u':
            printf("vowel\n");   /* executed */
            break;
        default:
            printf("consonant\n");
    }
    return 0;
}

Notes

Example in practice

int main() {
    // Pick one facility from this reference page.
    // Write the smallest program that exercises its main precondition,
    // complexity rule, or lifetime constraint before scaling up.
    return 0;
}