Virtual Public Inheritance

#include <iostream>
using namespace std;

class Device {
public:
    void show() {
        cout << "Generic Device\n";
    }
};

class Sensor : virtual public Device {
    // no extra code needed
};

class Actuator : virtual public Device {
    // no extra code needed
};

class SmartDevice : public Sensor, Actuator {
public:
    void identify() {
        cout << "Smart Device\n";
    }
};

int main() {
    SmartDevice sd;
    sd.show();      // from Device
    sd.identify();  // from SmartDevice
    return 0;
}