break statement

Causes the enclosing for, while or do-while loop or switch statement to terminate.

Used when it is otherwise awkward to terminate the loop using the condition expression and conditional statements.

Syntax

break ;

Appears only within the statement of a loop body (while, do, for) or within the statement of a switch.

Explanation

After this statement the control is transferred to the statement or declaration immediately following the enclosing loop or switch, as if by goto.

Keywords

break.

Notes

A break statement cannot be used to break out of multiple nested loops. The goto statement may be used for this purpose.

Example

#include <stdio.h>
 
int main(void)
{
    int i = 2;
    switch (i) {
        case 1: printf("1");
        case 2: printf("2");   // i==2, so execution starts at this case label
        case 3: printf("3");
        case 4:
        case 5: printf("45");
                break;         // execution of subsequent cases is terminated
        case 6: printf("6");
    }
    printf("\n");
 
    // Compare outputs from these two nested for loops.
    for (int j = 0; j < 2; j++) 
        for (int k = 0; k < 5; k++) 
            printf("%d%d ", j,k);
    printf("\n");
    for (int j = 0; j < 2; j++) {
        for (int k = 0; k < 5; k++) { // only this loop is exited by break
            if (k == 2) break;
            printf("%d%d ", j,k);
        }
    }
}

Output:

2345
00 01 02 03 04 10 11 12 13 14 
00 01 10 11

References

C11 standard (ISO/IEC 9899:2011):
- 6.8.6.3 The break statement (p: 153)
C99 standard (ISO/IEC 9899:1999):
- 6.8.6.3 The break statement (p: 138)
C89/C90 standard (ISO/IEC 9899:1990):
- 3.6.6.3 The break statement