1  /* Classify numbers as probable primes, primes or composites.
       2     With -q return true if the following argument is a (probable) prime.
       3  
       4  Copyright 1999, 2000, 2002, 2005, 2012 Free Software Foundation, Inc.
       5  
       6  This program is free software; you can redistribute it and/or modify it under
       7  the terms of the GNU General Public License as published by the Free Software
       8  Foundation; either version 3 of the License, or (at your option) any later
       9  version.
      10  
      11  This program is distributed in the hope that it will be useful, but WITHOUT ANY
      12  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
      13  PARTICULAR PURPOSE.  See the GNU General Public License for more details.
      14  
      15  You should have received a copy of the GNU General Public License along with
      16  this program.  If not, see https://www.gnu.org/licenses/.  */
      17  
      18  #include <stdlib.h>
      19  #include <string.h>
      20  #include <stdio.h>
      21  
      22  #include "gmp.h"
      23  
      24  char *progname;
      25  
      26  void
      27  print_usage_and_exit ()
      28  {
      29    fprintf (stderr, "usage: %s -q nnn\n", progname);
      30    fprintf (stderr, "usage: %s nnn ...\n", progname);
      31    exit (-1);
      32  }
      33  
      34  int
      35  main (int argc, char **argv)
      36  {
      37    mpz_t n;
      38    int i;
      39  
      40    progname = argv[0];
      41  
      42    if (argc < 2)
      43      print_usage_and_exit ();
      44  
      45    mpz_init (n);
      46  
      47    if (argc == 3 && strcmp (argv[1], "-q") == 0)
      48      {
      49        if (mpz_set_str (n, argv[2], 0) != 0)
      50  	print_usage_and_exit ();
      51        exit (mpz_probab_prime_p (n, 25) == 0);
      52      }
      53  
      54    for (i = 1; i < argc; i++)
      55      {
      56        int class;
      57        if (mpz_set_str (n, argv[i], 0) != 0)
      58  	print_usage_and_exit ();
      59        class = mpz_probab_prime_p (n, 25);
      60        mpz_out_str (stdout, 10, n);
      61        if (class == 0)
      62  	puts (" is composite");
      63        else if (class == 1)
      64  	puts (" is a probable prime");
      65        else /* class == 2 */
      66  	puts (" is a prime");
      67      }
      68    exit (0);
      69  }