text: #include <stdio.h>
  
  struct point {
  	int x;
  	int y;
  };
  
  struct point* addpoint(struct point* p1, const struct point* p2);
  
  
  int main(char argc, char** argv)
  {
  	struct point a;
  	struct point b;
  	struct point* c;
  
  	a.x = 1;
  	a.y = 1;
  
  	b.x = 2;
  	b.y = 2;
  
  	c = addpoint(&a, &b);
  
  	printf("c.x = %i\n", c->x);
  	printf("c.y = %i\n", c->y);
  
  	return 0;
  }
  
  struct point* addpoint(struct point* p1, const struct point* p2)
  {
  	p1->x += p2->x;
  	p1->y += p2->y;
  
  	return p1;
  }
  