#include<stdio.h>
#include<stdlib.h>
#include<math.h>   /* may still need gcc shapes1.c -lm */
#define PI 3.1415927

struct circle {
  int x;  int y;
  double radius;
};
typedef struct circle circle;

circle make_circle(int x, int y, double r) {
  struct circle C;
  C.x = x;
  C.y = y;
  C.radius = r;
  return C;  // copying elided by modern compilers upon return
}
double area_c(circle* this) { return this->radius*this->radius*PI; }
double circumference_c(circle* self) {  return self->radius*2*PI; }
double distance_c(circle* this, circle *other) {
  int dx = this->x - other->x;
  int dy = this->y - other->y;
  return sqrt((double)(dx*dx + dy*dy));  
}

struct rectangle {
  int x; int y;
  double width; double height;
};
typedef struct rectangle rectangle;

void make_rectangle(rectangle *this, int x, int y, double w, double h) {
  this->x=x;  this->y=y;  this->width=w;  this->height=h;
}// old C style, allocate memory "down stack"

double area_r(rectangle* this) {  return this->width*this->height; }
double circumference_r(rectangle* self) {
  return self->width*2 + self->height*2;
}
double distance_r(rectangle* this, rectangle *other) {
  int dx = this->x - other->x;
  int dy = this->y - other->y;
  return sqrt(dx*dx + dy*dy);  
}

int main() {
  circle C[2] = {make_circle(3,4,5), make_circle(50,60,10)};
  rectangle R[2];
  make_rectangle(R,3,4,5,6); make_rectangle(R+1,30,40,50,60);
  double totalarea = 0;
  int i = 0;
  for(;i<2;i++) { totalarea += area_c(C+i);  totalarea+= area_r(R+i); }
  printf("totalarea = %.2f\n",totalarea);
  return 0;
}//main