#include <stdio.h>

#include "geography.h"

/**
 * Computes the distance of a path given the latitudes and longitudes
 * of the points on the path.  The coordinates are read from standard input
 * and assumed to be in degrees.  The output is the number of points in the
 * path and the total distance using the great circle distance between adjacent
 * points.
 *
 * Compile and link with
 * gcc -Wall -std=c99 -pedantic distance.c
 * gcc -Wall -std=c99 -pedantic more_math.c
 * gcc -Wall -std=c99 -pedantic geography.c
 * gcc -o Distance distance.o more_math.o geography.o -lm
 *
 * @version 0.2 2018-09-06 colatitude now works in radians
 * @version 0.1 2017-09-01
 */
int main()
{
  double total_distance = 0.0;

  location prev;
  location curr;

  // upgraded to read user input (no more hard-coding) and calculate
  // the distance along a multi-point route (using a loop!)
  int n = 0;
  while (scanf("%lf %lf", &curr.lat, &curr.lon) == 2)
    {
      if (curr.lat < -90.0 || curr.lat > 90.0)
	{
	  fprintf(stderr, "Invalid latitude\n");
	  
	  return 1;
	}
      
      n++;

      
      if (n >= 2)
	{
	  total_distance += distance(&prev, &curr);
	}
      prev = curr;
    }
  
  printf("%d points; total distance %lf miles\n", n, total_distance);
}