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【c++之设计模式】组合使用:抽象工厂模式与单例模式

news 2025/9/11 22:36:17

简介

学以致用，使用抽象工厂及单例模式创建不同轿车及轿车装饰品。

代码

1. 定义一个抽象工厂类来创建不同类型的轿车和轿车装饰品。抽象工厂类中具有创建不同类型轿车和轿车装饰品的纯虚方法。

abstractFactory.h

#pragma once#include "Car.h"
#include "CarDecorate.h"class AbstractFactory
{
public:virtual Car* createCar() = 0;virtual CarDecorate* createDecorate() = 0;
};

2.定义不同类型的轿车，如 SUV 和跑车。

car.h

#pragma once#include <string>class Car
{
public:Car(std::string name) : m_name(name) {}virtual ~Car() {}std::string getName() const { return m_name; }private:std::string m_name;
};class SUV : public Car
{
public:SUV() : Car("SUV") {}
};class SportsCar : public Car
{
public:SportsCar() : Car("SportsCar") {}
};

3.定义不同类型的轿车装饰品，比如车载音响和真皮座椅。

carDecorate.h

#pragma once#include <string>class CarDecorate
{
public:CarDecorate(std::string name) : m_name(name) {}virtual ~CarDecorate() {}std::string getName() const { return m_name; }private:std::string m_name;
};class CarAudio : public CarDecorate
{
public:CarAudio() : CarDecorate("CarAudio") {}
};class LeatherSeat : public CarDecorate
{
public:LeatherSeat() : CarDecorate("LeatherSeat") {}
};

4.创建具体的工厂类，用于创建不同类型轿车及轿车装饰品。使用单例模式来确保每个工厂类只有一个实例。

suvFactory .h

#pragma once#include "AbstractFactory.h"class SUVFactory : public AbstractFactory
{
public:static SUVFactory* getInstance();virtual Car* createCar() override;virtual CarDecorate* createDecorate() override;private:SUVFactory() {}static SUVFactory* m_instance;
};class SportsCarFactory : public AbstractFactory
{
public:static SportsCarFactory* getInstance();virtual Car* createCar() override;virtual CarDecorate* createDecorate() override;private:SportsCarFactory() {}static SportsCarFactory* m_instance;
};

在实现工厂类时，使用单例模式创建工厂类的实例，确保每个工厂只有一个实例。实现工厂类的 createCar() 和 createDecorate() 方法，用于创建不同类型的轿车及轿车装饰品。

suvFactory.cpp

#include "SUVFactory.h"
#include "SportsCarFactory.h"SUVFactory* SUVFactory::m_instance = nullptr;
SportsCarFactory* SportsCarFactory::m_instance = nullptr;SUVFactory* SUVFactory::getInstance()
{if (m_instance == nullptr){m_instance = new SUVFactory();}return m_instance;
}Car* SUVFactory::createCar()
{return new SUV();
}CarDecorate* SUVFactory::createDecorate()
{return new LeatherSeat();
}SportsCarFactory* SportsCarFactory::getInstance()
{if (m_instance == nullptr){m_instance = new SportsCarFactory();}return m_instance;
}Car* SportsCarFactory::createCar()
{return new SportsCar();
}CarDecorate* SportsCarFactory::createDecorate()
{return new CarAudio();
}

5.可以使用工厂类来创建不同类型的轿车及轿车装饰品。

main.cpp

#include <iostream>
#include "SUVFactory.h"
#include "SportsCarFactory.h"int main()
{AbstractFactory* suvFactory = SUVFactory::getInstance();Car* suv = suvFactory->createCar();CarDecorate* suvDecorate = suvFactory->createDecorate();std::cout << suv->getName() << " with " << suvDecorate->getName() << std::endl;AbstractFactory* sportsCarFactory = SportsCarFactory::getInstance();Car* sportsCar = sportsCarFactory->createCar();CarDecorate* sportsCarDecorate = sportsCarFactory->createDecorate();std::cout << sportsCar->getName() << " with " << sportsCarDecorate->getName() << std::endl;return 0;
}