Question

I am using cygwin gcc version 4.5.3 to compile the following code.

 /* recursion.c */
int factorial_aux(int n, int t) {
    if (n <= 1) {
        return t;
    } else {
        return factorial_aux(n-1, n*t);
    }
}

int factorial(int n) {
    factorial_aux(n, 1);
}

int main() {
    int result = factorial(4);
    printf("%d\n", result);
}

Running the program compile with: gcc recursion.c -o recursion.exe prints 24, but the one compile with gcc -O2 recursion.c -o recursion.exe prints 0.

Could someone tell me why the different result? Any possible way to fix it?

Thanks!

Answer 1

Your factorial function is missing something. It doesn’t return anything.