结构型模式 装饰模式

适用于：  装饰者模式（Decorator Pattern）动态的给一个对象添加一些额外的职责。就增加功能来说，此模式比生成子类更为灵活。

/**
 * 结构型模式 装饰模式
 * 装饰（ Decorator ）模式又叫做包装模式。
 * 通过一种对客户端透明的方式来扩展对象的功能，是继承关系的一个替换方案。
 * 装饰模式就是把要添加的附加功能分别放在单独的类中，并让这个类包含它要装饰的对象，当需要执行时，客户端就可以有选择地、按顺序地使用装饰功能包装对象。
 *
 */

#define _CRT_SECURE_NO_WARNINGS

#include <iostream>
#include <string>

class Car
{
public:
    virtual void show() = 0;
};

class RunCar: public Car
{
public:
    void Run()
    {
        std::cout << "可以跑" << std::endl;
    }
    virtual void show() override
    {
        Run();
    }
};

class SwimCarDirector: public Car
{
public:
    SwimCarDirector(Car *car)
    {
        m_car = car;
    }
    void swim()
    {
        std::cout << "可以游" << std::endl;
    }
    virtual void show() override
    {
        m_car->show();
        swim();
    }
private:
    Car *m_car;
};

class FlyCarDirector:public Car
{
public:
    FlyCarDirector(Car *car)
    {
        m_car = car;
    }
    void Fly()
    {
        std::cout << "可以飞" << std::endl;
    }
    virtual void show() override
    {
        m_car->show();
        Fly();
    }
private:
    Car *m_car;
};

void mytest()
{
    Car *runcar = nullptr;
    runcar = new RunCar();
    runcar->show();

    std::cout << "车开始装饰 swim" << std::endl;
    SwimCarDirector *swimcar = new SwimCarDirector(runcar);
    swimcar->show();

    std::cout << "车开始装饰 fly" << std::endl;
    FlyCarDirector *flycar = new FlyCarDirector(runcar);
    flycar->show();

    delete flycar;
    flycar = nullptr;
    delete swimcar;
    swimcar = nullptr;
    delete runcar;
    runcar = nullptr;

    return;
}

int main()
{
    mytest();

    system("pause");
    return 0;
}