C++命令模式封装请求实现方法

class Command {
public:
    virtual ~Command() = default;
    virtual void execute() = 0;
};

class Light {
public:
    void on() { std::cout << "Light is on\n"; }
    void off() { std::cout << "Light is off\n"; }
};

class LightOnCommand : public Command {
    Light& light;
public:
    LightOnCommand(Light& l) : light(l) {}
    void execute() override { light.on(); }
};

class LightOffCommand : public Command {
    Light& light;
public:
    LightOffCommand(Light& l) : light(l) {}
    void execute() override { light.off(); }
};

class RemoteControl {
    std::unique_ptr<Command> command;
public:
    void setCommand(std::unique_ptr<Command> cmd) {
        command = std::move(cmd);
    }
    void pressButton() {
        if (command) command->execute();
    }
};

class Command {
public:
    virtual ~Command() = default;
    virtual void execute() = 0;
    virtual void undo() = 0;
};

class LightOnCommand : public Command {
    Light& light;
    bool wasOn = false;
public:
    LightOnCommand(Light& l) : light(l) {}
    void execute() override {
        wasOn = false; // 假设之前是关的
        light.on();
    }
    void undo() override {
        if (!wasOn) light.off();
    }
};