Can you explain the decorator pattern in C++ and Java with examples?

Can you explain the decorator pattern in C++ and Java with examples?

Sure! The decorator pattern allows behavior to be added to individual objects, either statically or dynamically, without affecting the behavior of other objects from the same class.

Can you provide a simple example in C++?

Absolutely! In C++, you might have a base class Coffee and a decorator class MilkDecorator that adds milk to the coffee. Here's a quick example:

class Coffee {
public:
    virtual double cost() { return 5.0; }
};

class MilkDecorator : public Coffee {
private:
    Coffee* coffee;
public:
    MilkDecorator(Coffee* c) : coffee(c) {}
    double cost() override { return coffee->cost() + 1.0; }
};

This way, you can add milk to any coffee object.

What about an example in Java?

In Java, the decorator pattern is quite similar. You can have an interface Coffee and a concrete class SimpleCoffee. Then, you can create a decorator like MilkDecorator:

interface Coffee {
    double cost();
}

class SimpleCoffee implements Coffee {
    public double cost() { return 5.0; }
}

class MilkDecorator implements Coffee {
    private Coffee coffee;
    public MilkDecorator(Coffee c) { this.coffee = c; }
    public double cost() { return coffee.cost() + 1.0; }
}

This allows you to dynamically add features to your coffee!