include <iostream>

include <string>

using namespace std;

//class goodBoy;
class Building{
//friend class goodBoy;
friend void goodBoy::visit();
public:
Building(){
this->m_SittingRoom = "客厅";
this->m_BeddingRoom = "卧室";
}
public:
string m_SittingRoom;
private:
string m_BeddingRoom;
};
class goodBoy{
public:
goodBoy(){
build = new Building;
}

void visit(){
    cout << "好朋友正在访问 " << this->build->m_SittingRoom << endl;
    cout << "好朋友正在访问 " << this->build->m_BeddingRoom << endl;
}

private:
Building * build;
};

void test03(){
goodBoy * boy = new goodBoy;
boy->visit();

}

int main(){
test03();
return 0;
}
这个为什么报error: use of undeclared identifier 'goodBoy'这个错误啊；小白一枚