SharedPtr_Cast_And_Destruction.cpp

#include "pch.h"
#include <iostream>
#include <memory>

using namespace std;

template<typename Object>
void Deleter(Object* obj)
{
	delete obj;
};

class A
{
	friend int main(void);

	template<typename Object>
	friend void Deleter(Object* obj);

public:
	int intA = 0;

protected:
	A( ) = default;
	virtual ~A( ) = default;
};

class B : public A
{
	friend int main(void);

	template<typename Object>
	friend void Deleter(Object* obj);

public:
	int intB = 10;

protected:
	B( ) = default;
	~B( ) = default;
};

int main()
{
	shared_ptr<B> b = shared_ptr<B>(new B, Deleter<B>);
	shared_ptr<A> a = shared_ptr<A>(new A, Deleter<A>);

	a->intA = 9999;
	cout << "a : " << a->intA << endl;
	cout << "a address: " << a.get( ) << endl;

	b->intA = -9999;
	b->intA = 1234;
	cout << "b : " << b->intA << ", " << b->intB << endl;
	cout << "b address: " << b.get( ) << endl << endl;

	cout << "dynamic_pointer_cast" << endl;
	a = dynamic_pointer_cast<A>(b);

	cout << "a : " << a->intA << endl;
	cout << "a address: " << a.get( ) << endl;

	return 0;
}

Result

a : 9999
a address: 00ACDC70
b : 1234, 10
b address: 00ACD880

dynamic_pointer_cast
a : 1234
a address: 00ACD880