Can you provide examples of the Factory design pattern in C++ and Java?

Can you provide examples of the Factory design pattern in C++ and Java?

Sure! The Factory design pattern is used to create objects without specifying the exact class of the object that will be created. In C++, you might have a base class Shape and derived classes like Circle and Square. The factory class would have a method like createShape() that returns a Shape pointer.

Can you show me the C++ code for that?

Absolutely! Here's a simple example:

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

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

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

class ShapeFactory {
public:
    static Shape* createShape(const std::string& type) {
        if (type == "Circle") return new Circle();
        else if (type == "Square") return new Square();
        return nullptr;
    }
};

You can call ShapeFactory::createShape("Circle") to create a Circle object.

What about Java? Can you provide a similar example?

Sure! Here's how you might implement the Factory pattern in Java:

abstract class Shape {
    abstract void draw();
}

class Circle extends Shape {
    void draw() { System.out.println("Drawing Circle"); }
}

class Square extends Shape {
    void draw() { System.out.println("Drawing Square"); }
}

class ShapeFactory {
    static Shape createShape(String type) {
        if (type.equalsIgnoreCase("Circle")) return new Circle();
        else if (type.equalsIgnoreCase("Square")) return new Square();
        return null;
    }
}

You can use ShapeFactory.createShape("Circle") to create a Circle object in Java.