#include <iostream>

double cube(double a);
double refcube(double &ra);

int main(void)
{
	using namespace std;
	double x = 3.0;
	
	cout << cube(x) << " = cube of " << x << endl;
	cout << refcube(x) << " = cube of  " << x << endl;
	
	return 0;
	
}

double cube(double a)
{
	a *= a * a;
	return a;
} 

double refcube(double &ra)
{
	ra*= ra * ra;
	return ra;
}