closure-test.c

#include <stdio.h>

void dotimes(void (*func)(void), int n)
{
    int i;
    for (i = 0; i < n; ++i)
    {
        func();
    }
}

int main()
{
    int level = 0;

    void level_upper() { level++; }

    printf("%d\n", level);

    dotimes(level_upper, 10);
    printf("%d\n", level);

    dotimes(level_upper, 5);
    printf("%d\n", level);

    return 0;
}

/*
 * masa@zola:$ ./closure.out 
 * 0
 * 10
 * 15
 * masa@zola:$ 
 */