友元：类友元、成员函数友元、全局函数友元

#include<iostream>
#include<string>
using namespace std;

class Building
{
friend class goodGay;//类作友元
//friend void visit（）全局函数作友元
friend void goodGay::visit();//成员函数作友元
public:
	
	Building()
	{
		this->m_sittingRoom = "客厅";
		this->m_bedRoom = "卧室";
	}
	string m_sittingRoom;
private:
	string m_bedRoom;
};
class goodGay
{
public:
	goodGay()
	{
		building = new Building;//给building指针开辟新内存
	};
	void visit()
	{
		cout << "好友正在访问" << building->m_sittingRoom << endl;
		cout << "好友正在访问" << building->m_bedRoom << endl;
	}
private:
	Building* building;//创建Building类型的指针，叫building
};
int main()
{
	goodGay gg;
	gg.visit();
}