// this program extracts lines, corresponding to 
// a definite particle from a .num file 

#include <math.h>
#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#include "escanf.h"

main (int argc, char* argv[])
{
    FILE *in, *out;
    char*  string1 = (char*) malloc (513 * sizeof (char)) ;
    int idt = 0;
    float variable ; 

    if ( ! (in = fopen (argv[1], "r"))) 
       { printf (" No input file \n") ; exit (0); 
       }
    if ( ! (out = fopen (argv[2], "w"))) 
       { printf (" Unable to create output file\n"); exit (0);
       } 
    if ( ( idt = atoi (argv[3]) ) < 10 ) 
       { printf (" Invalid particle id\n"); exit (0);
       }

 
    while ( fgets (string1, 512, in) )  {
       while ( escanf (string1, "%f", &variable) ) ;
       if ( fabsf ( fabsf (variable) - idt) < 1e-4  ) 
                  fputs (string1, out) ; 
   }

   fclose (in);
   fclose (out);
}