// Fig. 10.15: fig10_15.cpp
// Friends can access private members of a class.
#include <iostream>
using std::cout;
using std::endl;

// Count class definition
class Count
{
	friend void setX(Count &, int); // friend declaration
public:
	Count()
		: x(0) // initialize x to 0
	{
		// empty body
	} // end constructor Count

	// output x
	void print() const
	{
		 cout << x << endl;
	} // end function print
private:
	int x; // date member
}; // end class Count

// function setX can modify private date of Count
// because setX is declared as a friend of Count (line 10)
void SetX(Count &c, int val)
{
	c.x = val; // allowed because setX is a friend of Count
} // end function setX

int main()
{
	Count counter; // create Count object

	cout << "counter.x after instantiation: ";
	counter.print();

	setX(counter, 8); // set x using a friend function
	cout << "counter.x after call to setX friend function: ";
	counter.print();
	return 0;
} // end main