/* CSE303, Fall 2005, Homework 3, Problem 1 */

/* simple 2D-point manipulations */

#include <stdio.h>
#include <stdlib.h>

struct Point2D {
  double x;
  double y;
};
typedef struct Point2D point_t;

struct Line2D {
  double m; // slope
  double b; // intercept
};
typedef struct Line2D line_t;

void init_point(point_t * pt, double x, double y) {
  pt->x = x;
  pt->y = y;
}
void print_point(point_t * pt) {
  printf("\n(%g,%g)",pt->x,pt->y);
}
void init_line(line_t * line, double m, double b) {
  line->m = m;
  line->b = b;
}
void print_line(line_t * line) {
  printf("\ny = %g x + %g", line->m, line->b);
}

/* PUT YOUR FUNCTIONS HERE */

void points_test() {
  point_t points[15];
  line_t  lines[4];
  init_point(&points[0], 0.0, 0.0);
  init_point(&points[1], 5.0, 5.0);
  init_point(&points[2], 0.0, 1.0);
  init_point(&points[3], 5.0, 6.0);
  init_line(&lines[0], -1.0, -3.0);
  init_line(&lines[1], 0.0, 3.0);
  lines[2] = line_containing(points[0], points[1]);
  lines[3] = line_containing(points[2], points[3]);
  points[4] = intersect1(lines[0],lines[1]);
  points[5] = intersect1(lines[2],lines[3]);
  {point_t * new_point1 = intersect2(&lines[0],&lines[1]);
   point_t * new_point2 = intersect2(&lines[2],&lines[3]);
   point_t * new_point3 = intersect3(&lines[0],&lines[1]);
   point_t * new_point4 = intersect3(&lines[2],&lines[3]);
   points[6] = *new_point1;
   points[7] = *new_point2;
   points[8] = *new_point3;
   points[9] = *new_point4;
   free(new_point1);
   free(new_point2);
   free(new_point3);
   free(new_point4);
   intersect4(&points[10],&lines[0],&lines[1]);
   intersect4(&points[11],&lines[2],&lines[3]);
   {int ans1 = intersect5(&points[12],&lines[0],&lines[1]);
    int ans2 = intersect5(&points[13],&lines[2],&lines[3]);
    int i;
    for(i=0; i < 4; ++i)
      print_line(&lines[i]);
    for(i=0; i < 15; ++i)
      print_point(&points[i]);
    printf("\nans1=%d, ans2=%d\n",ans1,ans2);
   }}
}

int main(int argc, char**argv) {
  points_test();
  return 0;
}