Define Hello() as virtual on A allow us to redefine Hello() on Children but since B destructor will call A destructor at is exit and
A don't know if child have possible redefinition of Hello() he will call is own Hello() declaration.

struct A {
	virtual ~A() {
		Hello();
	}
	void Hello() const {
		Cout() << "Hello from A" << EOL;
	}
};

struct B : A {
	void Hello() const {
		Cout() << "Hello from B" << EOL;
	}
};