--- /dev/null
+/* -*-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 -------------------------------------------------*/