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

   1 /* -*-c-*-
   2  *
   3  * $Id: factorial.c,v 1.3 2002/01/13 19:51:59 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 1.3  2002/01/13 19:51:59  mdw
  34  * Provide proper help and options parsing.  Allow more bases.  Use
  35  * @mptext@ to read integers for the better base support.
  36  *
  37  * Revision 1.2  2001/06/16 13:22:59  mdw
  38  * Added command-line option to select output radix.
  39  *
  40  * Revision 1.1  2000/07/09 21:30:49  mdw
  41  * Demo program to compute factorials.
  42  *
  43  */
  44
  45 /*----- Header files ------------------------------------------------------*/
  46
  47 #include "config.h"
  48
  49 #include <ctype.h>
  50 #include <limits.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53
  54 #include <mLib/mdwopt.h>
  55 #include <mLib/quis.h>
  56 #include <mLib/report.h>
  57
  58 #include "mpint.h"
  59 #include "mpmul.h"
  60 #include "mptext.h"
  61
  62 /*----- Main code ---------------------------------------------------------*/
  63
  64 static void usage(FILE *fp)
  65 {
  66   pquis(fp, "Usage: $ [-r radix] integer\n");
  67 }
  68
  69 static void version(FILE *fp)
  70 {
  71   pquis(fp, "$, Catacomb version " VERSION "\n");
  72 }
  73
  74 static void help(FILE *fp)
  75 {
  76   version(fp);
  77   putc('\n', fp);
  78   usage(fp);
  79   fputs("\n\
  80 Prints the factorial of the given integer on its output.  Input may be\n\
  81 in decimal (the default), octal with preceding zero, hex with preceding\n\
  82 `0x', or any base N between 2 and 62 inclusive with preceding `N_'.\n\
  83 Output may be in any base between 2 and 62; the default is base 10.  For\n\
  84 bases between 11 and 36 inclusive, lowercase letters of either case are\n\
  85 used as additional digits with values 10 upwards; lowercase is always\n\
  86 used for output.  For bases between 37 and 62 inclusive, lowercase letters\n\
  87 have lower value than uppercase; hence `a' has the value 10, while `A' has\n\
  88 the value 36.\n\
  89 \n\
  90 Options provided:\n\
  91 \n\
  92 -h, --help              Display this help message.\n\
  93 -v, --version           Display the version number.\n\
  94 -u, --usage             Display a usage message.\n\
  95 \n\
  96 -r, --radix=N           Write output in base N.\n\
  97 ", fp);
  98 }
  99
 100 int main(int argc, char *argv[])
 101 {
 102   unsigned long x;
 103   int r = 10;
 104   char *p;
 105   mp *f, *ulmax, *xx;
 106   unsigned fl = 0;
 107
 108 #define f_bogus 1u
 109
 110   ego(argv[0]);
 111
 112   for (;;) {
 113     static const struct option opt[] = {
 114       { "help",         0,              0,      'h' },
 115       { "version",      0,              0,      'v' },
 116       { "usage",        0,              0,      'u' },
 117       { "radix",        OPTF_ARGREQ,    0,      'r' },
 118       { 0,              0,              0,      0 }
 119     };
 120     int i = mdwopt(argc, argv, "hvur:", opt, 0, 0, 0);
 121     if (i < 0)
 122       break;
 123     switch (i) {
 124       case 'h':
 125         help(stdout);
 126         exit(0);
 127       case 'v':
 128         version(stdout);
 129         exit(0);
 130       case 'u':
 131         usage(stdout);
 132         exit(0);
 133       case 'r':
 134         r = atoi(optarg);
 135         if (r < 2 || r > 62)
 136           die(EXIT_FAILURE, "bad radix `%s'", optarg);
 137         break;
 138       default:
 139         fl |= f_bogus;
 140         break;
 141     }
 142   }
 143
 144   if (optind + 1 != argc || (fl & f_bogus)) {
 145     usage(stderr);
 146     exit(EXIT_FAILURE);
 147   }
 148   ulmax = mp_fromulong(MP_NEW, ULONG_MAX);
 149   p = argv[optind];
 150   while (isspace((unsigned char)*p))
 151     p++;
 152   xx = mp_readstring(MP_NEW, argv[optind], &p, 0);
 153   while (isspace((unsigned char)*p))
 154     p++;
 155   if (!xx || *p || MP_CMP(xx, >, ulmax))
 156     die(EXIT_FAILURE, "bad integer `%s'", argv[optind]);
 157   x = mp_toulong(xx);
 158   mp_drop(xx);
 159   mp_drop(ulmax);
 160   f = mp_factorial(x);
 161   mp_writefile(f, stdout, r);
 162   fputc('\n', stdout);
 163   mp_drop(f);
 164   return (0);
 165 }
 166
 167 /*----- That's all, folks -------------------------------------------------*/