//
// Program name:  factorial_function
// Author:  B. Massingill
//
// This program defines and tests a factorial function.
//
// Input, output:  see program text
//
#include <iostream.h>
//
// Function name:  factorial
//
// Precondition:
//	n is positive
// Postcondition:
//	return value is n factorial
//
// Note that we don't say what this function does if n is not positive.
// So to use this function appropriately, you should be sure to 
//	call it only with positive n.
//
int factorial(int n);
//
// Main program
//
int main()
{
	int n;
	cout << "Enter a positive integer\n";
	cin >> n;
	if (n > 0)
		cout << n << " factorial is " << factorial(n) << endl;
	else
		cout << "Not a positive integer\n";
	return 0;
}
// code for factorial function (see above for function documentation)
int factorial(int n)
{
	int valueToReturn = 1 ;
	for (int i = 2; i <= n; i++)
		valueToReturn *= i;
	return valueToReturn;
}