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

#define N 3

#define MAX_CHAR 30

main()
{
  int i;
  double x[N], sum=0.0;

  char filename[MAX_CHAR];
  FILE *ifp;
  double num;

  /*
  printf("enter the three numbers to be summed\n" );
  if(scanf("%lf %lf %lf", &x[0],&x[1],&x[2]) != 3)
    {
      printf("please enter 3 numbers");
      exit(1);
    }
  for(i=0; i< N; i++)
      sum += fabs( x[i] ) ;

  printf("the sum is %lf\n", sum);

  */

  printf("enter the filename containing numbers\n " );
  scanf("%s", &filename) ;

  ifp = fopen(filename, "r");
  while ( fscanf(ifp, "%lf", &num) ==1)
    {
      sum +=fabs( num );
    }

  printf("\nthe sum is %lf\n", sum);

}