(1)这个代码的逻辑是在一个类中创建另一个类的指针，通过new动态内存分配来将，building指向Building类的一个对象

【1】这个代码将函数定义在类外

using namespace std;
class Building;
class GoodGay{
	public:
		GoodGay();
		void visit();
		Building *building;
};
class Building{
	friend class GoodGay;
	public:
		Building();
	public:
		string m_SittingRoom;
	private:
		string m_BedRoom;
};
Building::Building(){
	m_SittingRoom="客厅";
	m_BedRoom="卧室";
}
GoodGay::GoodGay(){
	building= new Building;
}
void GoodGay::visit(){
	cout<<"好基友类正在访问: "<<building->m_BedRoom<<endl;
}
void test01(){
	GoodGay gg;
	gg.visit();
}
int main()
{
	test01();
}

代码的关键点：friend class GoodGay;将类转换为友元类