#include <stdio.h>

int fact(int n);

int main() {
    printf("factorial is %d\n",fact(7));
    return 0;
}

int fact(int n){
    if (n==0){   //this is a base case (which is necessary) wich stops the condition
        return 1;
    }
    int factNm1 = fact(n-1);
    int factN =factNm1 * n;
    return factN;
}