#include <stdio.h>//修正後
 
struct a_xy {
    int x;
    int y;
};
 
struct b_xy {
    int x;
    int y;
};
 
int main(void)
{
    struct a_xy a = {10, 20};
    struct b_xy b = {30, 40};
 
    a.x = b.x;
    printf("a.x = %d\n", a.x);
 
    a.x = b.x;
    a.y = b.y;
 
    printf("a.y = %d\n", a.y);
 
    return 0;
}