int GreatestCommonDivisor(int x, int y)
int LeastCommonMultiple(int x, int y)
void ReduceFraction(int& numerator,int& denominator)
void MakeDenominatorsCommon(int& numerator1,int& denominator1,
			   int& numerator2,int& denominator2)



#include<iostream>
#include<time.h>
using namespace std;

//by copy vs. by reference

//reference - antoher name for a variable, does not make a copy
void square(int& i)
{
	i = i * i;
}

void main()
{
	int i = 3;
	square( i );
	
	// you can not pass a literal to a function whose parameter is a reference
	//square( 8 );

	cout << i << endl;
}