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

   1 /* -*-c-*-
   2  *
   3  * $Id: factorial.c,v 1.4 2004/04/08 01:36:15 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 /*----- Header files ------------------------------------------------------*/
  31
  32 #include "config.h"
  33
  34 #include <ctype.h>
  35 #include <limits.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38
  39 #include <mLib/mdwopt.h>
  40 #include <mLib/quis.h>
  41 #include <mLib/report.h>
  42
  43 #include "mpint.h"
  44 #include "mpmul.h"
  45 #include "mptext.h"
  46
  47 /*----- Main code ---------------------------------------------------------*/
  48
  49 static void usage(FILE *fp)
  50 {
  51   pquis(fp, "Usage: $ [-r RADIX] INTEGER\n");
  52 }
  53
  54 static void version(FILE *fp)
  55 {
  56   pquis(fp, "$, Catacomb version " VERSION "\n");
  57 }
  58
  59 static void help(FILE *fp)
  60 {
  61   version(fp);
  62   putc('\n', fp);
  63   usage(fp);
  64   fputs("\n\
  65 Prints the factorial of the given integer on its output.  Input may be\n\
  66 in decimal (the default), octal with preceding zero, hex with preceding\n\
  67 `0x', or any base N between 2 and 62 inclusive with preceding `N_'.\n\
  68 Output may be in any base between 2 and 62; the default is base 10.  For\n\
  69 bases between 11 and 36 inclusive, lowercase letters of either case are\n\
  70 used as additional digits with values 10 upwards; lowercase is always\n\
  71 used for output.  For bases between 37 and 62 inclusive, lowercase letters\n\
  72 have lower value than uppercase; hence `a' has the value 10, while `A' has\n\
  73 the value 36.\n\
  74 \n\
  75 Options provided:\n\
  76 \n\
  77 -h, --help              Display this help message.\n\
  78 -v, --version           Display the version number.\n\
  79 -u, --usage             Display a usage message.\n\
  80 \n\
  81 -r, --radix=N           Write output in base N.\n\
  82 ", fp);
  83 }
  84
  85 int main(int argc, char *argv[])
  86 {
  87   unsigned long x;
  88   int r = 10;
  89   char *p;
  90   mp *f, *ulmax, *xx;
  91   unsigned fl = 0;
  92
  93 #define f_bogus 1u
  94
  95   ego(argv[0]);
  96
  97   for (;;) {
  98     static const struct option opt[] = {
  99       { "help",         0,              0,      'h' },
 100       { "version",      0,              0,      'v' },
 101       { "usage",        0,              0,      'u' },
 102       { "radix",        OPTF_ARGREQ,    0,      'r' },
 103       { 0,              0,              0,      0 }
 104     };
 105     int i = mdwopt(argc, argv, "hvur:", opt, 0, 0, 0);
 106     if (i < 0)
 107       break;
 108     switch (i) {
 109       case 'h':
 110         help(stdout);
 111         exit(0);
 112       case 'v':
 113         version(stdout);
 114         exit(0);
 115       case 'u':
 116         usage(stdout);
 117         exit(0);
 118       case 'r':
 119         r = atoi(optarg);
 120         if (r < 2 || r > 62)
 121           die(EXIT_FAILURE, "bad radix `%s'", optarg);
 122         break;
 123       default:
 124         fl |= f_bogus;
 125         break;
 126     }
 127   }
 128
 129   if (optind + 1 != argc || (fl & f_bogus)) {
 130     usage(stderr);
 131     exit(EXIT_FAILURE);
 132   }
 133   ulmax = mp_fromulong(MP_NEW, ULONG_MAX);
 134   p = argv[optind];
 135   while (isspace((unsigned char)*p))
 136     p++;
 137   xx = mp_readstring(MP_NEW, argv[optind], &p, 0);
 138   while (isspace((unsigned char)*p))
 139     p++;
 140   if (!xx || *p || MP_CMP(xx, >, ulmax))
 141     die(EXIT_FAILURE, "bad integer `%s'", argv[optind]);
 142   x = mp_toulong(xx);
 143   mp_drop(xx);
 144   mp_drop(ulmax);
 145   f = mp_factorial(x);
 146   mp_writefile(f, stdout, r);
 147   fputc('\n', stdout);
 148   mp_drop(f);
 149   return (0);
 150 }
 151
 152 /*----- That's all, folks -------------------------------------------------*/