Question

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C: for loop int initial declaration

Can we declare some variables in for statement in C programming?If so,in which version of c standard will we find the feature?

Answer 1

In C89/C90, all declarations have to appear at the beginning of a block:

/* valid in C89/C90 */
printf("Hello\n");
{
    int i;
    for (i = 0; i < 10; i++) {
        int j = i % 3;
        printf("%d\n", j);
    }
}

Starting with C99 you can mix declarations and statements, and declare variables in the first part of a for:

/* valid in C99 */
printf("Hello\n");
int whatever;
for (int i = 0; i < 10; i++) {
    int j = i % 3;
    printf("%d\n", j);
}