#include <iostream>
#include <memory>
using namespace std;
 
class Base {
private:
	// data members
public:
	Base() { cout << "Base created" << endl; }
	Base(const Base &) { cout << "Base copied" << endl; }
	virtual ~Base() { cout << "Base destroyed" << endl; }
	// ...
	virtual Base* clone() const = 0;
};
 
class Derived : public Base{
private:
	// more data members
public:
	Derived(){ cout << "Derived created" << endl; }
	Derived(const Derived &){ cout << "Derived copied" << endl; }
	~Derived(){ cout << "Derived destroyed" << endl; }
	// ...
	Derived* clone() const override {
		return new Derived(*this);
	}
};
 
class DecoratedDerived : public Base {
private:
    unique_ptr<Base> ptr;
    // ...
public:
	DecoratedDerived()
		: Base(), ptr(new Derived)
	{
		cout << "DecoratedDerived created" << endl;
	}
    DecoratedDerived(const DecoratedDerived &src)
        : Base(src), ptr(src.ptr ? src.ptr->clone() : nullptr)
    {
		cout << "DecoratedDerived copied" << endl;
    }
	~DecoratedDerived() {
		cout << "DecoratedDerived destroyed" << endl;
	}
    // ...
    DecoratedDerived* clone() const override{
        return new DecoratedDerived(*this);
    }
};
 
int main()
{
	cout << "creating DecoratedDerived..." << endl;
    auto *p_d = new DecoratedDerived;
    cout << endl;
 
	cout << "cloning DecoratedDerived..." << endl;
    auto *p_clone = p_d->clone();
    cout << endl;
 
	cout << "destroying clone..." << endl;
    delete p_clone;
    cout << endl;
 
	cout << "destroying DecoratedDerived..." << endl;
    delete p_d;
    cout << endl;
 
	return 0;
}

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