成员函数作为友元

关键代码
friend void goodgay::visit();
表示goodgay类中的成员函数visit()作为本类的好朋友

 1 #include<bits/stdc++.h>
using namespace std;

class Building;
class goodgay
{
public:
    goodgay();

    void visit();//可访问Building中的私有成员

    void visit1();//不可访问Building中的私有成员

    Building *building;
};

class Building
{
    friend void goodgay::visit();
    //表示goodgay类中的成员函数visit()作为本类的好朋友
public:
    Building();

public:
    string sittingroom;

private:
    string bedroom;

};

Building::Building()
{
    sittingroom = "sittingroom";
    bedroom = "bedroom";
}

goodgay::goodgay()
{
    building = new Building;
}

void goodgay::visit()
{
    cout << "00 goodgay is visitting " << building->sittingroom << endl;
    cout << "00 goodgay is visitting " << building->bedroom << endl;
}

void goodgay::visit1()
{
    cout << "01 goodgay is visitting " << building->sittingroom << endl;
    //cout << "goodgay is visitting " << building->bedroom << endl;
}

void test()
{
    goodgay gg;
    gg.visit();
    gg.visit1();
}

int main()
{
    test();
    return 0;
}