/****************************************
 * Program that shows how a more complex
 * example may be solved in C.  By the
 * end of the semester, the code in this
 * program will be fully understood by
 * CSC230 students.
 ***************************************/

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

/****************************************
 * Function header that takes the 
 * difference of the two ints provided
 * as parameters
 ***************************************/
static int compute_length (int, int);

/****************************************
 * Starts the program and handles the 
 * user interaction
 ***************************************/
int
main (void)
{
  //Create data structure for use in program
  typedef struct
  {
    int left;
    int right;
    int length;
  } seg_t;

  //Create pointers to instances of the 
  //data structure
  seg_t *seg1, *seg2;

  //Allocate memory for each instance of the
  //data structure
  seg1 = (seg_t *) malloc (sizeof (seg_t));
  seg2 = (seg_t *) malloc (sizeof (seg_t));

  //Get user input and assign to appropriate
  //members of data structure
  printf ("Enter left edge of segment 1: ");
  scanf ("%d", &(seg1->left));
  printf ("Enter right edge of segment 1: ");
  scanf ("%d", &(seg1->right));
  printf ("Enter left edge of segment 2: ");
  scanf ("%d", &(seg2->left));
  printf ("Enter right edge of segment 2: ");
  scanf ("%d", &(seg2->right));

  //Use the computer_length method to calculate
  //appropriate values and assign to memeber
  seg1->length = compute_length (seg1->left, seg1->right);
  seg2->length = compute_length (seg2->left, seg2->right);

  //Do final comparison and print message
  if (seg1->length == seg2->length) {
      printf ("Segment lengths are equal\n");
  }  else{
      printf ("Segment lengths are NOT equal\n");
  }

  //Always return something
  return 0;
}

/***************************************
 * Returns the difference between left
 * and right
 **************************************/
int
compute_length (int left, int right)
{
  return (right - left);
}