Write a function that calculates the factorial of a given number n! recursively.

Experts: The function shall calculate fib(n) instead of n!.

###Hints###

For which n is the result of n! clear?

Check for such n at the start of the function!

For all other n, you need a recursive call.

Experts: In one statement, you can call a function multiple times

##Solution##

#include <stdio.h>

int fak(int n);

int main(void) {
    int n;
    printf("Gimme numba: ");
    scanf("%d", &n);

    printf("fak(%d) = %d\n", n, fak(n));
    return 0;
}

int fak(int n) {
    if (n <= 1)
        return 1;

    return n * fak(n - 1);
}

Experts:

#include <stdio.h>

int fib(int n);

int main(void) {
    int n;
    printf("fib(?): ");
    scanf("%d", &n);

    if (n < 0)
        printf("Srsly? -.-\n");

    printf("fib(%d) = %d\n", n, fib(n));
    return 0;
}

int fib(int n) {
    if (n <= 1)
        return n;

    return fib(n - 1) + fib(n - 2);
}