#include <stdio.h>
    struct calculation1
    {
        int n[2];
    };
    struct calculation2
    {
        int *n;
    };
    int main()
    {
        struct calculation1 cal1 = {10, 20};
        struct calculation2 *ptr1;
        ptr1->n = (struct q*)&cal1.n;
        printf("%d\n", ptr1->n[1]);
    }