X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/progs/factorial.c

diff --git a/progs/factorial.c b/progs/factorial.c
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+/* -*-c-*-
+ *
+ * Example factorial computation
+ *
+ * (c) 2000 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "config.h"
+
+#include <ctype.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <mLib/mdwopt.h>
+#include <mLib/quis.h>
+#include <mLib/report.h>
+
+#include "mpint.h"
+#include "mpmul.h"
+#include "mptext.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+static void usage(FILE *fp)
+{
+  pquis(fp, "Usage: $ [-r RADIX] INTEGER\n");
+}
+
+static void version(FILE *fp)
+{
+  pquis(fp, "$, Catacomb version " VERSION "\n");
+}
+
+static void help(FILE *fp)
+{
+  version(fp);
+  putc('\n', fp);
+  usage(fp);
+  fputs("\n\
+Prints the factorial of the given integer on its output.  Input may be\n\
+in decimal (the default), octal with preceding zero, hex with preceding\n\
+`0x', or any base N between 2 and 62 inclusive with preceding `N_'.\n\
+Output may be in any base between 2 and 62; the default is base 10.  For\n\
+bases between 11 and 36 inclusive, lowercase letters of either case are\n\
+used as additional digits with values 10 upwards; lowercase is always\n\
+used for output.  For bases between 37 and 62 inclusive, lowercase letters\n\
+have lower value than uppercase; hence `a' has the value 10, while `A' has\n\
+the value 36.\n\
+\n\
+Options provided:\n\
+\n\
+-h, --help		Display this help message.\n\
+-v, --version		Display the version number.\n\
+-u, --usage		Display a usage message.\n\
+\n\
+-r, --radix=N		Write output in base N.\n\
+", fp);
+}
+
+int main(int argc, char *argv[])
+{
+  unsigned long x;
+  int r = 10;
+  char *p;
+  mp *f, *ulmax, *xx;
+  unsigned fl = 0;
+
+#define f_bogus 1u
+
+  ego(argv[0]);
+
+  for (;;) {
+    static const struct option opt[] = {
+      { "help",		0,		0,	'h' },
+      { "version",	0,		0,	'v' },
+      { "usage",	0,		0,	'u' },
+      { "radix",	OPTF_ARGREQ,	0,	'r' },
+      { 0,		0,		0,	0 }
+    };
+    int i = mdwopt(argc, argv, "hvur:", opt, 0, 0, 0);
+    if (i < 0)
+      break;
+    switch (i) {
+      case 'h':
+	help(stdout);
+	exit(0);
+      case 'v':
+	version(stdout);
+	exit(0);
+      case 'u':
+	usage(stdout);
+	exit(0);
+      case 'r':
+	r = atoi(optarg);
+	if (r < 2 || r > 62)
+	  die(EXIT_FAILURE, "bad radix `%s'", optarg);
+	break;
+      default:
+	fl |= f_bogus;
+	break;
+    }
+  }
+
+  if (optind + 1 != argc || (fl & f_bogus)) {
+    usage(stderr);
+    exit(EXIT_FAILURE);
+  }
+  ulmax = mp_fromulong(MP_NEW, ULONG_MAX);
+  p = argv[optind];
+  while (isspace((unsigned char)*p))
+    p++;
+  xx = mp_readstring(MP_NEW, argv[optind], &p, 0);
+  while (isspace((unsigned char)*p))
+    p++;
+  if (!xx || *p || MP_CMP(xx, >, ulmax))
+    die(EXIT_FAILURE, "bad integer `%s'", argv[optind]);
+  x = mp_toulong(xx);
+  mp_drop(xx);
+  mp_drop(ulmax);
+  f = mp_factorial(x);
+  mp_writefile(f, stdout, r);
+  fputc('\n', stdout);
+  mp_drop(f);
+  return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/