设计模式-装饰器模式（Decorator Pattern）

装饰器模式允许在运行时动态地给一个对象添加一些额外的职责，而不会影响到其他对象。
在C++中，装饰器模式可以通过定义一个抽象组件类和多个装饰器类来实现。

class Component {
public:
    virtual void Operation() = 0;
};

class ConcreteComponent : public Component {
public:
    void Operation() override {
        std::cout << "ConcreteComponent operation." << std::endl;
    }
};

class Decorator : public Component {
public:
    Decorator(Component* component) : component_(component) {}

    void Operation() override {
        component_->Operation();
    }

protected:
    Component* component_;
};

class ConcreteDecoratorA : public Decorator {
public:
    ConcreteDecoratorA(Component* component) : Decorator(component) {}

    void Operation() override {
        Decorator::Operation();
        std::cout << "Added ConcreteDecoratorA operation." << std::endl;
    }
};

class ConcreteDecoratorB : public Decorator {
public:
    ConcreteDecoratorB(Component* component) : Decorator(component) {}

    void Operation() override {
        Decorator::Operation();
        std::cout << "Added ConcreteDecoratorB operation." << std::endl;
    }
};