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

   1 /* -*-c-*-
   2  *
   3  * Example factorial computation
   4  *
   5  * (c) 2000 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "config.h"
  31
  32 #include <ctype.h>
  33 #include <limits.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36
  37 #include <mLib/mdwopt.h>
  38 #include <mLib/quis.h>
  39 #include <mLib/report.h>
  40
  41 #include "mpint.h"
  42 #include "mpmul.h"
  43 #include "mptext.h"
  44
  45 /*----- Main code ---------------------------------------------------------*/
  46
  47 static void usage(FILE *fp)
  48 {
  49   pquis(fp, "Usage: $ [-r RADIX] INTEGER\n");
  50 }
  51
  52 static void version(FILE *fp)
  53 {
  54   pquis(fp, "$, Catacomb version " VERSION "\n");
  55 }
  56
  57 static void help(FILE *fp)
  58 {
  59   version(fp);
  60   putc('\n', fp);
  61   usage(fp);
  62   fputs("\n\
  63 Prints the factorial of the given integer on its output.  Input may be\n\
  64 in decimal (the default), octal with preceding zero, hex with preceding\n\
  65 `0x', or any base N between 2 and 62 inclusive with preceding `N_'.\n\
  66 Output may be in any base between 2 and 62; the default is base 10.  For\n\
  67 bases between 11 and 36 inclusive, lowercase letters of either case are\n\
  68 used as additional digits with values 10 upwards; lowercase is always\n\
  69 used for output.  For bases between 37 and 62 inclusive, lowercase letters\n\
  70 have lower value than uppercase; hence `a' has the value 10, while `A' has\n\
  71 the value 36.\n\
  72 \n\
  73 Options provided:\n\
  74 \n\
  75 -h, --help              Display this help message.\n\
  76 -v, --version           Display the version number.\n\
  77 -u, --usage             Display a usage message.\n\
  78 \n\
  79 -r, --radix=N           Write output in base N.\n\
  80 ", fp);
  81 }
  82
  83 int main(int argc, char *argv[])
  84 {
  85   unsigned long x;
  86   int r = 10;
  87   char *p;
  88   mp *f, *ulmax, *xx;
  89   unsigned fl = 0;
  90
  91 #define f_bogus 1u
  92
  93   ego(argv[0]);
  94
  95   for (;;) {
  96     static const struct option opt[] = {
  97       { "help",         0,              0,      'h' },
  98       { "version",      0,              0,      'v' },
  99       { "usage",        0,              0,      'u' },
 100       { "radix",        OPTF_ARGREQ,    0,      'r' },
 101       { 0,              0,              0,      0 }
 102     };
 103     int i = mdwopt(argc, argv, "hvur:", opt, 0, 0, 0);
 104     if (i < 0)
 105       break;
 106     switch (i) {
 107       case 'h':
 108         help(stdout);
 109         exit(0);
 110       case 'v':
 111         version(stdout);
 112         exit(0);
 113       case 'u':
 114         usage(stdout);
 115         exit(0);
 116       case 'r':
 117         r = atoi(optarg);
 118         if (r < 2 || r > 62)
 119           die(EXIT_FAILURE, "bad radix `%s'", optarg);
 120         break;
 121       default:
 122         fl |= f_bogus;
 123         break;
 124     }
 125   }
 126
 127   if (optind + 1 != argc || (fl & f_bogus)) {
 128     usage(stderr);
 129     exit(EXIT_FAILURE);
 130   }
 131   ulmax = mp_fromulong(MP_NEW, ULONG_MAX);
 132   p = argv[optind];
 133   while (isspace((unsigned char)*p))
 134     p++;
 135   xx = mp_readstring(MP_NEW, argv[optind], &p, 0);
 136   while (isspace((unsigned char)*p))
 137     p++;
 138   if (!xx || *p || MP_CMP(xx, >, ulmax))
 139     die(EXIT_FAILURE, "bad integer `%s'", argv[optind]);
 140   x = mp_toulong(xx);
 141   mp_drop(xx);
 142   mp_drop(ulmax);
 143   f = mp_factorial(x);
 144   mp_writefile(f, stdout, r);
 145   fputc('\n', stdout);
 146   mp_drop(f);
 147   return (0);
 148 }
 149
 150 /*----- That's all, folks -------------------------------------------------*/