git.distorted.org.uk Git - u/mdw/catacomb/blob - factorial.c

   1 /* -*-c-*-
   2  *
   3  * $Id: factorial.c,v 1.2 2001/06/16 13:22:59 mdw Exp $
   4  *
   5  * Example factorial computation
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: factorial.c,v $
  33  * Revision 1.2  2001/06/16 13:22:59  mdw
  34  * Added command-line option to select output radix.
  35  *
  36  * Revision 1.1  2000/07/09 21:30:49  mdw
  37  * Demo program to compute factorials.
  38  *
  39  */
  40
  41 /*----- Header files ------------------------------------------------------*/
  42
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45
  46 #include <mLib/mdwopt.h>
  47 #include <mLib/quis.h>
  48 #include <mLib/report.h>
  49
  50 #include "mpmul.h"
  51
  52 /*----- Main code ---------------------------------------------------------*/
  53
  54 int main(int argc, char *argv[])
  55 {
  56   unsigned long x;
  57   int r = 10;
  58   char *p;
  59   mp *f;
  60
  61   ego(argv[0]);
  62
  63   for (;;) {
  64     static const struct option opt[] = {
  65       { "radix",        OPTF_ARGREQ,    0,      'r' },
  66       { 0,              0,              0,      0 }
  67     };
  68     int i = mdwopt(argc, argv, "r:", opt, 0, 0, 0);
  69     if (i < 0)
  70       break;
  71     switch (i) {
  72       case 'r':
  73         r = atoi(optarg);
  74         if (r < 2 || r > 36)
  75           die(EXIT_FAILURE, "bad radix `%s'", optarg);
  76         break;
  77       default:
  78         exit(EXIT_FAILURE);
  79     }
  80   }
  81
  82   if (optind + 1 != argc) {
  83     pquis(stderr, "Usage: $ [-r radix] integer\n");
  84     exit(EXIT_FAILURE);
  85   }
  86   x = strtoul(argv[optind], &p, 0);
  87   if (*p)
  88     die(EXIT_FAILURE, "bad integer `%s'", argv[optind]);
  89   f = mp_factorial(x);
  90   mp_writefile(f, stdout, r);
  91   fputc('\n', stdout);
  92   mp_drop(f);
  93   return (0);
  94 }
  95
  96 /*----- That's all, folks -------------------------------------------------*/