/*
    gdb_test.c
    Jeff Ondich, 14 February 2022
    Major simplifications, 17 Oct 2023

    Compile like this:

        gcc -o gdb_test -Wall -Werror -g -Og gdb_test.c
*/

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

int factorial(int n) {
    if (n <= 1) {
        return 1;
    }

    int result = factorial(n - 1);
    result = n * result;
    return result;
}

void print_usage(char *command_name) {
    fprintf(stderr, "Usage: %s [integer]\n", command_name);
}

int main(int argc, char *argv[]) {
    if (argc != 2) {
        print_usage(argv[0]);
        return 1;
    }

    int n = 0;
    int matches = sscanf(argv[1], "%d", &n);
    if (matches != 1) { // what's this about?
        print_usage(argv[0]);
        return 1;
    }

    int result = factorial(n);
    printf("%d! = %d\n", n, result);

    return 0;
}