/* Last edited on 2009-10-31 17:34:53 by stolfi */

double parse_double ( int *argn, int argc, char **argv, double lo, double hi )
  { char *rest;
    double x;
    if (*argn >= argc) 
      { arg_error("argument value is missing", (*argn)-1, argv[(*argn)-1]); }
    x = strtod(argv[*argn], &rest);
    if (*rest != '\0') 
      { arg_error("invalid number", *argn, argv[*argn]); } 
    if ((x < lo) || (x > hi)) 
      { arg_error("out of range", *argn, argv[*argn]); }
    ++(*argn);
    return x;
  }