#include <stdio.h>

 struct xy {
 int x;
 int y;
 };

 struct zw {
 int z;
 struct xy w;
 };

 int main(void)
 {
 struct zw a;
 struct zw b = {10, {20, 30}};
 struct zw c = {40, {50, 60}};

 a.z = b.z;
 printf("a.z = %d\n", a.z);

 a.w.x = b.w.x;
 printf("a.w.x = %d\n", a.w.x);

 a.w = b.w;
 printf("a.w.y = %d\n", a.w.y);

 a = c;
 printf("a.z = %d\n", a.z);
 printf("a.w.x = %d\n", a.w.x);
 printf("a.w.y = %d\n", a.w.y);

 return 0;
 }