/* 
* Koen Noens, december 2002
* oefening functies
* call by reference
*/

# include <iostream.h>

void fac (int n, long &result);

void main()
{
	int getal;
	long faculteit;
	
	// input
	cout << "functie : faculteit"<<endl
		<< "getal : ";
	cin >> getal;

	// call function
	fac(getal, faculteit);

	//result 
	cout << "fac() : " << faculteit << endl << endl;


}

void fac (int n, long &result)
{
	//init
	result = 1;

	
	if (n <= 0)
	// berekening niet uitvoeren
	{
		result = 0;
	}
	else
	{
		for (int i = 1; i <= n; i++)
		{
			result *= i;
		}
	}

}