C++ elegantly clone derived class by calling base class

Question

I have a need to clone a derived class given only a reference or pointer to the base class. The following code does the job, but doesn\'t seem elegant, because I\'m putting

Answer 1

You can rely on the CRTP idiom.
It follows a minimal, working example:

struct B {
    ~virtual ~B() { }
    virtual B* clone() = 0;
};

template
struct D: public B {
    B* clone() {
        return new C{*static_cast(this)};
    }
};

struct S: public D { };

int main() {
    B *b1 = new S;
    B *b2 = b1->clone();
    delete b1;
    delete b2;
}