Hackfest.cpp

// Factorial of n = 1*2*3*...*n

#include <iostream>
using namespace std;

int factorial(int);

int main() {
 int n, result;

 cout << "Enter a non-negative number: ";
 cin >> n;

 result = factorial(n);
 cout << "Factorial of " << n << " = " << result;
 return 0;
}

int factorial(int n) {
 if (n > 1) {
 return n * factorial(n - 1);
 } else {
 return 1;
 }
}