C++中的生成器模式

目录

生成器模式（Builder Pattern）

实际应用

构建一辆汽车

构建一台计算机

构建一个房子

总结

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生成器模式（Builder Pattern）

生成器模式是一种创建型设计模式，它允许你分步骤创建复杂对象。与其他创建型模式不同的是，生成器模式允许你在一个过程中创建一个对象，而无需等待所有部分都准备好。这种模式特别适用于需要构造不同表示或状态的复杂对象时。

实际应用

1. 需要构造的对象包含多个部分，且需要分步骤创建。
2. 希望使用相同的创建过程来构造不同表示的对象。
3. 构造过程需要能够被隔离和独立变化。

构建一辆汽车

假设我们有一个`Car`类，它有很多可选属性，例如车的颜色、发动机类型、轮胎类型等等。

#include <iostream>
#include <string>class Car {
public:std::string color;std::string engine;std::string tires;std::string interior;void show() {std::cout << "Car Details:\n"<< "Color: " << color << "\n"<< "Engine: " << engine << "\n"<< "Tires: " << tires << "\n"<< "Interior: " << interior << "\n";}
};class CarBuilder {
private:Car car;
public:CarBuilder& setColor(const std::string& color) {car.color = color;return *this;}CarBuilder& setEngine(const std::string& engine) {car.engine = engine;return *this;}CarBuilder& setTires(const std::string& tires) {car.tires = tires;return *this;}CarBuilder& setInterior(const std::string& interior) {car.interior = interior;return *this;}Car build() {return car;}
};int main() {CarBuilder builder;Car car = builder.setColor("Red").setEngine("V8").setTires("Sport").setInterior("Leather").build();car.show();return 0;
}

构建一台计算机

假设我们有一个`Computer`类，它有很多可选属性，例如CPU类型、RAM大小、存储类型和大小等等。

#include <iostream>
#include <string>class Computer {
public:std::string cpu;int ram;std::string storageType;int storageSize;void show() {std::cout << "Computer Details:\n"<< "CPU: " << cpu << "\n"<< "RAM: " << ram << " GB\n"<< "Storage Type: " << storageType << "\n"<< "Storage Size: " << storageSize << " GB\n";}
};class ComputerBuilder {
private:Computer computer;
public:ComputerBuilder& setCPU(const std::string& cpu) {computer.cpu = cpu;return *this;}ComputerBuilder& setRAM(int ram) {computer.ram = ram;return *this;}ComputerBuilder& setStorageType(const std::string& storageType) {computer.storageType = storageType;return *this;}ComputerBuilder& setStorageSize(int storageSize) {computer.storageSize = storageSize;return *this;}Computer build() {return computer;}
};int main() {ComputerBuilder builder;Computer computer = builder.setCPU("Intel i9").setRAM(32).setStorageType("SSD").setStorageSize(1024).build();computer.show();return 0;
}

构建一个房子

假设我们有一个`House`类，它有很多可选属性，例如房间数量、楼层数量、花园是否存在、是否有车库等等。

#include <iostream>
#include <string>class House {
public:int rooms;int floors;bool garden;bool garage;void show() {std::cout << "House Details:\n"<< "Rooms: " << rooms << "\n"<< "Floors: " << floors << "\n"<< "Garden: " << (garden ? "Yes" : "No") << "\n"<< "Garage: " << (garage ? "Yes" : "No") << "\n";}
};class HouseBuilder {
private:House house;
public:HouseBuilder& setRooms(int rooms) {house.rooms = rooms;return *this;}HouseBuilder& setFloors(int floors) {house.floors = floors;return *this;}HouseBuilder& setGarden(bool garden) {house.garden = garden;return *this;}HouseBuilder& setGarage(bool garage) {house.garage = garage;return *this;}House build() {return house;}
};int main() {HouseBuilder builder;House house = builder.setRooms(5).setFloors(2).setGarden(true).setGarage(true).build();house.show();return 0;
}

总结

每个生成器类负责设置对象的各个属性，并在最终构建出对象。