generator.c

#include <stdio.h>

// A generator that generates 0..10 infinitely
int generator(void) {
    static int i, state = 0;
    switch (state) {
        case 0: goto LABEL0;
        case 1: goto LABEL1;
    }

LABEL0: /* start of function */

    for (i = 0; i < 10; i++) {
        state = 1;
        return i;
LABEL1:;
    }
    goto LABEL0;
}

int main() {
    // Will print 1..10, then 1..10 again
    for (int j = 0; j < 20; j++) {
        printf("%d\n", generator());
    }
}