class Base {

public:
    virtual void doSomething() {
        cout << "Base::doSomething()" << endl;
    }

};

class Derived : public Base {

private:
    void doSomething() override {
        cout << "Derived::doSomething()" << endl;
    }

};


int main(int argc, char* argv[])
{
    auto b = unique_ptr<Base>(new Base);
    b->doSomething();

    auto b2 = unique_ptr<Base>(new Derived);
    b2->doSomething();

    auto d = unique_ptr<Derived>(new Derived);
    d->doSomething();

    return 0;
}