/**
 * fak.c
 * Copyright (C) 2008 Markus Broeker
 */

#include <stdio.h>
#include <stdlib.h>

unsigned long fak (short i)
{
    if (i == 0)
        return 1;
    else if (i > 0)
        return (i * fak (i - 1));
    else
        return (i * fak (i + 1));
}

int main (int argc, char **argv)
{
    short number;

    printf ("Enter a number: ");
    if (scanf ("%hd", &number) != 1) {
        printf ("READ ERROR\n");
        return EXIT_FAILURE;
    }

    if (number < 0) {
        printf ("NUMBER FORMAT ERROR\n");
        return EXIT_FAILURE;
    }

    printf ("The faktorial of %d is %lu\n", number, fak (number));

    return EXIT_SUCCESS;
}