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

struct House
{
    virtual House* clone() = 0;
    virtual string name() = 0;    
};
    
struct Person
{
    House *housePtr = nullptr;

    Person() : housePtr(nullptr) {}

    void assignHouse(House* ptr)
    {
        housePtr = ptr;
    }

    string houseName() { if (housePtr == nullptr) return "NULL"; else return housePtr->name(); }
        
    // copy constructor, housePtr should be same type as rhs housePtr
    Person(const Person& rhs)
    {
        housePtr = rhs.housePtr != nullptr ? rhs.housePtr->clone() : nullptr;
    }
};

struct GlassHouse : public House
{
    virtual House* clone() { return new GlassHouse; }
    virtual string name() { return "GlassHouse"; }
};

struct BrickHouse : public House
{
    virtual House* clone() { return new BrickHouse; }
    virtual string name() { return "BrickHouse"; }    
};

int main(void)
{
    GlassHouse gh;
    BrickHouse bh;
    Person a;    
    a.assignHouse(&gh);
    Person b(a);    
    cout << a.houseName() << endl;
    cout << b.houseName() << endl;

    Person c;
    c.assignHouse(&bh);
    Person d(c);    
    
    cout << c.houseName() << endl;
    cout << d.houseName() << endl;

    Person e;
    Person f(e);
    cout << e.houseName() << endl;
    cout << f.houseName() << endl;    
}