C++全局函数做友元

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

class Building
{
    friend void GoodFriend(Building building);    //全局函数做友元

public:
    Building()
    {
        SittingRoom = "客厅";
        BedRoom = "卧室";
    }

public:
    string SittingRoom;

private:
    string BedRoom;
};

void GoodFriend(Building building)
{
    cout << "好朋友正在访问" << building.SittingRoom << endl;
    cout << "好朋友正在访问" << building.BedRoom << endl;
}

int _tmain(int argc, _TCHAR* argv[])
{
    Building b;
    GoodFriend(b);
    
    system("pause");
    return 0;
}