#include <iostream>
using namespace std;

class TLightSource
{
  private:
    int lightState;

    virtual void Light(void) = 0;
    virtual void Dark (void) = 0;
    
  public:
    TLightSource() {lightState = 0;}
    void TurnOn (void) { if(!lightState) Light(); lightState = 1;}
    void TurnOff (void) { if(lightState) Dark(); lightState = 0;}
    int IsOn(void) {return (lightState != 0);}
};

class TTungstenBulb : public TLightSource
{
    private:
	int LightStrength;
        virtual void Light(void);
        virtual void Dark(void);
    public:
	
	void SetStrength(int s){
		if(s<101 && s>-1){LightStrength=s;}
	}
	
	int ShowStrength(void){
		return LightStrength;
	}
};

void TTungstenBulb::Light(void)
{
        cout << "Turning this tungsten bulb ON...\n";
}

void TTungstenBulb::Dark(void)
{
        cout << "Turning this tungsten bulb OFF...\n";
}

int main(void)
{
        TTungstenBulb MyLamp;

        cout << "Initial status " << MyLamp.IsOn() << "\n";
        MyLamp.TurnOn();
        cout << "Current status " << MyLamp.IsOn() << "\n";
        MyLamp.TurnOn(); // What's happening if we turn on some more times?
   	MyLamp.SetStrength(50);
	cout<< "Currenth strength is: "<< MyLamp.ShowStrength()<<endl;
        MyLamp.TurnOff();
	cout<< "Currenth strength is: "<< MyLamp.ShowStrength()<<endl;
        cout << "Current status " << MyLamp.IsOn() << "\n";

        return 0;
}