/* Exercise mpz_fac_ui.

Copyright 2000, 2001, 2002 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>
#include "mpir.h"
#include "gmp-impl.h"
#include "tests.h"


/* Usage: t-fac_ui [x|num]

   With no arguments testing goes up to the initial value of "limit" below.
   With a number argument tests are carried that far, or with a literal "x"
   tests are continued without limit (this being meant only for development
   purposes).  */


int
main (int argc, char *argv[])
{
  unsigned long  n;
  unsigned long  limit = 1500;
  mpz_t          f, r;

  tests_start ();

  if (argc > 1 && argv[1][0] == 'x')
    limit = ULONG_MAX;
  else if (argc > 1)
    limit = atoi (argv[1]);

  /* for small limb testing */
  limit = MIN (limit, MP_LIMB_T_MAX);

  mpz_init_set_ui (f, 1);  /* 0! = 1 */
  mpz_init (r);

  for (n = 0; n < limit; n++)
    {
      mpz_fac_ui (r, n);
      MPZ_CHECK_FORMAT (r);

      if (mpz_cmp (f, r) != 0)
        {
          printf ("mpz_fac_ui(%lu) wrong\n", n);
          printf ("  got  "); mpz_out_str (stdout, 10, r); printf("\n");
          printf ("  want "); mpz_out_str (stdout, 10, f); printf("\n");
          abort ();
        }

      mpz_mul_ui (f, f, n+1);  /* (n+1)! = n! * n */
    }

  mpz_clear (f);
  mpz_clear (r);

  tests_end ();

  exit (0);
}