/* nag_bessel_y0 (s17acc) Example Program.
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 2 revised, 1992.
 */

#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nags.h>

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  Integer  exit_status = 0;
  double   x, y;
  NagError fail;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n]");
  fprintf(fpout, "nag_bessel_y0 (s17acc) Example Program Results\n");
  fprintf(fpout, "     x           y\n");
  while (fscanf(fpin, "%lf", &x) != EOF)
    {
      /* nag_bessel_y0 (s17acc).
       * Bessel function Y_0(x)
       */
      y = nag_bessel_y0(x, &fail);
      if (fail.code != NE_NOERROR)
        {
          fprintf(fpout, "Error from nag_bessel_y0 (s17acc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
      fprintf(fpout, "%12.3e%12.3e\n", x, y);
    }

 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  return exit_status;
}