1.工厂模式（Factory Method）

注：图片来源于 https://www.cnblogs.com/-saligia-/p/10216752.html

工厂UML图解析：

工厂模式：client用户需要三步：

1.创建工厂；

2.生产产品对象；

3.使用对象方法。

代码：

工厂类 Factory.h

//
// Created by Halo on 2019/10/14.
//

#ifndef FACTORY_FACTORY_H
#define FACTORY_FACTORY_H

#include "Product.h"

//抽象手机工厂类
class Factory {
public:
    //生产手机
    virtual Phone* CreatePhone() = ;

};

//OPPO手机工厂
class OPPOFactory : public Factory {
public:
    //OPPO手机工厂类 use a OPPO手机类
    Phone* CreatePhone() override {
        return new OPPO();
    }
};

//VIVO手机工厂
class VIVOFactory : public Factory {
public:
    Phone* CreatePhone() override {
        return new VIVO();
    }
};

//HUAWEI手机工厂
class HUAWEIFactory : public Factory {
public:
    Phone* CreatePhone() override {
        return new HUAWEI();
    }
};

//XIAOMI手机工厂
class XIAOMIFactory : public Factory {
public:
    Phone* CreatePhone() override {
        return new XIAOMI();
    }
};

#endif //FACTORY_FACTORY_H

产品类 Product.h

//
// Created by Halo on 2019/10/14.
//

#ifndef FACTORY_PRODUCT_H
#define FACTORY_PRODUCT_H

#include <string>

//抽象手机类
class Phone {
public:
    //Phone() = default;;
    //得到手机名称
    virtual std::string Say() = ;
    //~Phone() = default;
};

//具体手机类：OPPO
class OPPO : public Phone {
public:
    //OPPO() = default;
    std::string Say() override {
        return "OPPO 音乐手机！";
    }
    //~OPPO() = default;
};
//具体手机类：VIVO
class VIVO : public Phone {
public:
    //VIVO() = default;
    std::string Say() override {
        return "VIVO 照相手机！";
    }
    //~VIVO() = default;
};
//具体手机类：HUAWEI
class HUAWEI : public Phone {
public:
    //HUAWEI() = default;
    std::string Say() override {
        return "HUAWEI 商务手机！";
    }
    //~HUAWEI() = default;
};
//具体手机类：XIAOMI
class XIAOMI : public Phone {
public:
    //XIAOMI() = default;
    std::string Say() override {
        return "XIAOMI 性价比手机！";
    }
    //~XIAOMI() = default;
};

#endif //FACTORY_PRODUCT_H

用户 main.cpp

#include <iostream>
#include "Factory.h"
using namespace std;

int main() {
    //创建OPPO手机工厂
    Factory* f1 = new OPPOFactory();
    //OPPO手机工厂制造手机
    Phone* p1 =  f1->CreatePhone();
    //OPPO手机口号
    cout << p1->Say() << endl;

    Factory* f2 = new VIVOFactory();
    Phone* p2 = f2->CreatePhone();
    cout << p2->Say() << endl;

    Factory* f3 = new HUAWEIFactory();
    Phone* p3 = f3->CreatePhone();
    cout << p3->Say() << endl;

    Factory* f4 = new XIAOMIFactory();
    Phone* p4 = f4->CreatePhone();
    cout << p4->Say() << endl;

    return ;
}