#include <iostream>
#include <cstdlib>
using namespace std;

int factorial(int i);

int main()
{

	//Output the product of the ints from 1 to 10 inclusive.
	cout << factorial(10) << "\n";

	return EXIT_SUCCESS;
}

//Return the product of the ints from 1 to n inclusive.

int factorial(int n)
{
	if (n < 0) {
		cerr << "Can't take the factorial of a negative number.\n";
		exit(EXIT_FAILURE);
	}

	int f {1};

	for (int i {1}; i <= n; ++i) {
	       f *= i;   //means f = f * i;
	}	

	return f;
}