本文主要是介绍C++中的外观模式，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
目录
外观模式（Facade Pattern）
实际应用
计算机启动系统
家庭影院系统
旅行预订系统
总结
外观模式（Facade Pattern）
外观模式是一种结构型设计模式，它为复杂子系统提供一个更高级的统一接口，使得子系统更容易使用。外观模式隐藏了系统的复杂性，并向客户端提供了一个简化的接口。
通过外观模式，客户端不需要直接与子系统的各个组件交互，而是通过一个外观对象与整个子系统进行交互，从而简化了客户端的操作。
实际应用
计算机启动系统
假设有一个复杂的计算机启动系统，包括CPU、内存、硬盘等多个组件。
#include <iostream>// 子系统类：CPU
class CPU {
public:void freeze() {std::cout << "Freezing CPU\n";}void jump(long position) {std::cout << "Jumping to position " << position << "\n";}void execute() {std::cout << "Executing instructions\n";}
};// 子系统类：内存
class Memory {
public:void load(long position, const std::string& data) {std::cout << "Loading data into memory at position " << position << "\n";}
};// 子系统类：硬盘
class HardDrive {
public:std::string read(long lba, int size) {std::cout << "Reading " << size << " bytes from LBA " << lba << "\n";return "bootloader";}
};// 外观类
class ComputerFacade {
private:CPU cpu;Memory memory;HardDrive hardDrive;public:void start() {cpu.freeze();memory.load(0, hardDrive.read(0, 1024));cpu.jump(0);cpu.execute();}
};int main() {ComputerFacade computer;computer.start();return 0;
}
家庭影院系统
假设有一个复杂的家庭影院系统，包括投影仪、音响、DVD播放器等多个组件。
#include <iostream>// 子系统类：投影仪
class Projector {
public:void on() {std::cout << "Turning on the projector\n";}void off() {std::cout << "Turning off the projector\n";}void setInput(const std::string& input) {std::cout << "Setting projector input to " << input << "\n";}
};// 子系统类：音响
class SoundSystem {
public:void on() {std::cout << "Turning on the sound system\n";}void off() {std::cout << "Turning off the sound system\n";}void setVolume(int level) {std::cout << "Setting sound system volume to " << level << "\n";}
};// 子系统类：DVD播放器
class DVDPlayer {
public:void on() {std::cout << "Turning on the DVD player\n";}void off() {std::cout << "Turning off the DVD player\n";}void play(const std::string& movie) {std::cout << "Playing movie: " << movie << "\n";}
};// 外观类
class HomeTheaterFacade {
private:Projector projector;SoundSystem soundSystem;DVDPlayer dvdPlayer;public:void watchMovie(const std::string& movie) {std::cout << "Get ready to watch a movie...\n";projector.on();projector.setInput("DVD");soundSystem.on();soundSystem.setVolume(10);dvdPlayer.on();dvdPlayer.play(movie);}void endMovie() {std::cout << "Shutting down movie theater...\n";projector.off();soundSystem.off();dvdPlayer.off();}
};int main() {HomeTheaterFacade homeTheater;homeTheater.watchMovie("Inception");homeTheater.endMovie();return 0;
}
旅行预订系统
假设有一个复杂的旅行预订系统，包括航班预订、酒店预订和租车预订等多个组件。
#include <iostream>// 子系统类：航班预订
class FlightBooking {
public:void bookFlight(const std::string& destination) {std::cout << "Booking flight to " << destination << "\n";}
};// 子系统类：酒店预订
class HotelBooking {
public:void bookHotel(const std::string& location) {std::cout << "Booking hotel in " << location << "\n";}
};// 子系统类：租车预订
class CarRentalBooking {
public:void bookCar(const std::string& location) {std::cout << "Booking car rental in " << location << "\n";}
};// 外观类
class TravelFacade {
private:FlightBooking flightBooking;HotelBooking hotelBooking;CarRentalBooking carRentalBooking;public:void bookCompleteTrip(const std::string& destination) {std::cout << "Booking complete trip to " << destination << "...\n";flightBooking.bookFlight(destination);hotelBooking.bookHotel(destination);carRentalBooking.bookCar(destination);}
};int main() {TravelFacade travelFacade;travelFacade.bookCompleteTrip("Hawaii");return 0;
}
总结
外观模式可以简化复杂子系统的使用。所以无论是计算机启动系统、家庭影院系统还是旅行预订系统，外观模式都能提供一个简化的接口，使客户端能够更容易地与复杂子系统进行交互。
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