#include <stdio.h>

struct A
{
    int i;
    char c;
};

int main()
{
    union {
        struct A a;
        int i[2];
    } u;

    memset(&u.a, 0, sizeof u.a);
    printf("%d\n", u.i[1]);

    u.a.c = 1000;
    printf("%d\n", u.i[1]);

    return 0;
}