/*---------------------------------------------------------------------------
  Program: CalcPol
  Content: Calculates the extent of a polygon
  Author:  Jürgen Plakolb - S0810307029@students.fh-hagenberg.at
  Date : 17.10.2009
---------------------------------------------------------------------------*/

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

int main(int argc, char *argv[])
{
   int i;
   double dx, dy;
   double extent, distance;
   if(argc <= 5) {
     printf("Error in %s: wrong amount of arguments!\n", argv[0]);
     printf("3 Points are necessary! \n");
     exit(-1);
   }
   else if (argc % 2 == 0) {
     printf("Error in %s: wrong amount of arguments!\n", argv[0]);
     printf("for each point two coordinates are necessary! \n");
     printf("%d Elemente", argc);
     exit(-1);
   }
   else {
     for (i = 1; i <= (argc - 2); i += 2) {
       printf("P%d (%s | %s)\n", (i / 2), argv[i], argv[i+1]);
     }
     /*Calculation  of extent*/
     extent = 0.0;
     for (i = 1; i < (argc - 3); i += 2) {
       dx = atoi(argv[i]) - atoi(argv[i + 2]);
       dy = atoi(argv[i + 1]) - atoi(argv[i + 3]);
       distance = sqrt(pow(dx, 2) + pow(dy, 2));
       extent += distance;
     }
     dx = abs(atoi(argv[1]) - atoi(argv[argc - 2]));
     dy = abs(atoi(argv[2]) - atoi(argv[argc - 1]));
     distance = sqrt(pow(dx, 2) + pow(dy, 2));
     extent += distance;
     printf("\nUmfang= %.2f \n", extent);
   }
   return 0;
}