#include #include #include #include using namespace std; class SmartDevice; class SmartHomeMediator { public: virtual ~SmartHomeMediator() = default; virtual void notify(SmartDevice* device, const string& event) = 0; virtual void registerDevice(SmartDevice* device) = 0; }; class SmartDevice { protected: SmartHomeMediator* mediator; string name; public: SmartDevice(SmartHomeMediator* mediator, const string& name) : mediator(mediator), name(name) {} virtual ~SmartDevice() = default; string getName() const { return name; } virtual void receiveCommand(const string& command) = 0; }; // Colleagues class Thermostat : public SmartDevice { int temperature = 72; public: Thermostat(SmartHomeMediator* mediator, const string& name) : SmartDevice(mediator, name) {} void setTemperature(int temp) { temperature = temp; cout << name << ": Temperature set to " << temp << endl; if (temp > 75) { mediator->notify(this, "TEMP_HIGH"); } else { mediator->notify(this, "TEMP_NORMAL"); } } void receiveCommand(const string& command) override { // Thermostat does not respond to commands } }; class Lights : public SmartDevice { public: Lights(SmartHomeMediator* mediator, const string& name) : SmartDevice(mediator, name) {} void receiveCommand(const string& command) override { if (command == "ON") { cout << name << ": Turned ON" << endl; } else if (command == "OFF") { cout << name << ": Turned OFF" << endl; } } }; class AirConditioner : public SmartDevice { public: AirConditioner(SmartHomeMediator* mediator, const string& name) : SmartDevice(mediator, name) {} void receiveCommand(const string& command) override { if (command == "ON") { cout << name << ": Turned ON" << endl; } else if (command == "OFF") { cout << name << ": Turned OFF" << endl; } } }; // Concrete Mediator class SmartHomeHub : public SmartHomeMediator { vector devices; public: void registerDevice(SmartDevice* device) override { devices.push_back(device); } void notify(SmartDevice* device, const string& event) override { if (event == "TEMP_HIGH") { cout << "[SmartHomeHub] TEMP_HIGH detected. Turning on AC." << endl; for (auto d : devices) { if (dynamic_cast(d)) { d->receiveCommand("ON"); } } } else if (event == "TEMP_NORMAL") { cout << "[SmartHomeHub] TEMP_NORMAL detected. Turning off AC." << endl; for (auto d : devices) { if (dynamic_cast(d)) { d->receiveCommand("OFF"); } } } else if (event == "NIGHT_MODE") { cout << "[SmartHomeHub] NIGHT_MODE activated. Turning off lights." << endl; for (auto d : devices) { if (dynamic_cast(d)) { d->receiveCommand("OFF"); } } } } }; int main() { SmartHomeHub hub; Thermostat thermostat(&hub, "Living Room Thermostat"); Lights lights(&hub, "Living Room Lights"); AirConditioner ac(&hub, "Central AC"); hub.registerDevice(&thermostat); hub.registerDevice(&lights); hub.registerDevice(&ac); thermostat.setTemperature(80); thermostat.setTemperature(70); hub.notify(&lights, "NIGHT_MODE"); return 0; }

Exercise: Mediator Design Pattern

Exercise 1: Smart Home Controller

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