sealed(final) class in C++

SealedBase.cpp

#include <iostream>
using namespace std;

// Use 2 language features:
// 1. Derived classes through private inheritance can access base class's protected member, but make it private to its sub classes
// 2. Virtual inheritance will cause the final derived class to call the virtual bases's constructor directly
// so the sealed class has no problem to create instance while its sub class can't create instance.
// This is also another use of CRTP (curious recurring template pattern)
template <class T>
class SealedBase
{
protected:
	SealedBase(){}
};

#define Sealed(class_name) private virtual SealedBase<class_name>

class Dog : Sealed(Dog)
{
};

class BigDog: public Dog
{
};

int main(int argc, const char* argv[])
{
	Dog d;
	
	//BigDog bd;
	//BigDog* pBg = new BigDog();
	
	cout << "Hello, World" << endl;
	return 0;
}