桥接模式 C++实现

桥接模式：将抽象部分与实现部分分离，使它们都可以独立的变化。
主要解决：在有多种可能会变化的情况下，用继承会造成类爆炸问题，扩展起来不灵活。
何时使用：实现系统可能有多个角度分类，每一种角度都可能变化。

//
//  main.cpp
//  bridge_pattern
//
//  Created by apple on 2019/4/11.
//  Copyright © 2019年 apple. All rights reserved.
//

#include <iostream>
using namespace std;

class ISport
{//运动接口
public:
    virtual ~ISport() {}
    virtual void do_sport(int time) = 0;
};

class run:public ISport
{//跑步类
public:
    void do_sport(int time)
    {
        cout<<"run "<<time<<" min"<<endl;
    }
};
class swim:public ISport
{//游泳类
public:
    void do_sport(int time)
    {
        cout<<"swim "<<time<<" min"<<endl;
    }
};
class fly:public ISport
{//飞行类
public:
    void do_sport(int time)
    {
        cout<<"fly "<<time<<" min"<<endl;
    }
};

class IBridge
{//桥接接口
public:
    virtual ~IBridge() {}
    virtual void do_sport() = 0;
};
class Client:public IBridge
{//桥接实体类，真实场景中可能存在多个桥接实体类
private:
    int time;
    ISport *sport = NULL;
public:
    Client(int time, ISport *sport)
    {
        this->time = time;
        this->sport = sport;
    }
    ~Client()
    {
        delete sport;
        sport = NULL;
    }
    void do_sport()
    {
        sport->do_sport(time);
    }
};



int main(int argc, const char * argv[]) {
    IBridge *bridge = NULL;
    
    bridge = new Client(10, new run());
    bridge->do_sport();
    delete bridge;
    
    bridge = new Client(8, new swim());
    bridge->do_sport();
    delete bridge;
    
    bridge = new Client(6, new fly());
    bridge->do_sport();
    delete bridge;
    return 0;
}

run 10 min
swim 8 min
fly 6 min
Program ended with exit code: 0