#include <iostream>
#include <memory>

using namespace std;

class Shape {
public:
    virtual void draw() = 0;
};

class Circle : public Shape {
public:
    virtual void draw() override {
        cout << "Circle draw" << endl;
    }
};

class Square : public Shape {
public:
    virtual void draw() override {
        cout << "Square draw" << endl;
    }
};

class Factory {
public:
    unique_ptr<Shape> generate(const string& s) {
        if (s == "circle") {
            return make_unique<Circle>();
        } else if (s == "square") {
            return make_unique<Square>();
        }

        return nullptr;
    }
};

int main() {
    Factory f;
    unique_ptr<Shape> s = f.generate("circle");
    s->draw();
    s = f.generate("square");
    s->draw();
}