C++ 设计模式-建造者模式

以下是一个完整的C++建造者模式示例，包含产品类、建造者接口、具体建造者、指挥者以及测试代码：

#include <iostream>
#include <string>
#include <memory>// 产品类：汽车
class Car {
public:void setBody(const std::string& body) { m_body = body; }void setEngine(const std::string& engine) { m_engine = engine; }void setWheels(int wheels) { m_wheels = wheels; }void setElectronics(const std::string& electronics) { m_electronics = electronics; }void show() const {std::cout << "Car Details:\n"<< "Body: " << m_body << "\n"<< "Engine: " << m_engine << "\n"<< "Wheels: " << m_wheels << "\n"<< "Electronics: " << m_electronics << "\n\n";}private:std::string m_body;std::string m_engine;int m_wheels = 0;std::string m_electronics;
};// 抽象建造者
class CarBuilder {
public:virtual ~CarBuilder() = default;virtual void buildBody() = 0;virtual void buildEngine() = 0;virtual void buildWheels() = 0;virtual void buildElectronics() = 0;virtual Car getResult() = 0;
};// 具体建造者：运动型汽车
class SportsCarBuilder : public CarBuilder {
public:void buildBody() override { m_car.setBody("Carbon Fiber Body"); }void buildEngine() override { m_car.setEngine("V8 Twin Turbo"); }void buildWheels() override { m_car.setWheels(4); }void buildElectronics() override { m_car.setElectronics("Racing Package"); }Car getResult() override { return std::move(m_car); }private:Car m_car;
};// 具体建造者：家用汽车
class FamilyCarBuilder : public CarBuilder {
public:void buildBody() override { m_car.setBody("Steel Body"); }void buildEngine() override { m_car.setEngine("1.6L Inline-4"); }void buildWheels() override { m_car.setWheels(4); }void buildElectronics() override { m_car.setElectronics("Basic Package"); }Car getResult() override { return std::move(m_car); }private:Car m_car;
};// 指挥者
class Director {
public:void setBuilder(CarBuilder* builder) { m_builder = builder; }void constructCar() {m_builder->buildBody();m_builder->buildEngine();m_builder->buildWheels();m_builder->buildElectronics();}private:CarBuilder* m_builder;
};// 测试代码
int main() {Director director;// 建造运动型汽车SportsCarBuilder sportsBuilder;director.setBuilder(&sportsBuilder);director.constructCar();Car sportsCar = sportsBuilder.getResult();sportsCar.show();// 建造家用汽车FamilyCarBuilder familyBuilder;director.setBuilder(&familyBuilder);director.constructCar();Car familyCar = familyBuilder.getResult();familyCar.show();return 0;
}

输出结果：

Car Details:
Body: Carbon Fiber Body
Engine: V8 Twin Turbo
Wheels: 4
Electronics: Racing PackageCar Details:
Body: Steel Body
Engine: 1.6L Inline-4
Wheels: 4
Electronics: Basic Package

代码结构说明：

1. Car类：最终要构建的复杂对象，包含车身、发动机、轮子等组件

2. CarBuilder抽象类：

   • 定义构建汽车各个组件的接口
   • 包含4个纯虚函数用于构建不同部件
   • 提供获取最终产品的接口

3. 具体建造者：

   • SportsCarBuilder：实现运动型汽车的建造细节
   • FamilyCarBuilder：实现家用汽车的建造细节
   • 每个具体建造者维护自己的Car实例

4. Director类：

   • 控制建造流程
   • 定义建造顺序（先车身→发动机→轮子→电子设备）
   • 通过组合不同的建造者来创建不同产品

5. 测试代码：

   • 演示如何使用建造者模式创建不同类型的产品
   • 通过切换建造者来改变最终产品
   • 保持创建过程的一致性