C++ :

#include <iostream>
using namespace std;
class Rectangle
{
public:
    Rectangle(double l, double w);
    Rectangle() {}
  double CalArea();
protected:                              
    double length;
    double width;
};

class Rectangular:public Rectangle
{
public:
    Rectangular(double l, double w, double h);
    double CalVolume();
  
private:
    double height;
};

Rectangle::Rectangle(double l, double w)
{
        length = l;
        width = w;
}



Rectangular::Rectangular(double l, double w, double h):Rectangle(l,w),height(h)                       
{}

double Rectangle::CalArea()
{
    return length*width;
}

double Rectangular::CalVolume()
{
    return height*width*length;
}

int main()
{
    double l,w,h;
	cin>>l>>w;
	Rectangle rectangle(l,w);
    cout<<rectangle.CalArea()<<endl;
	cin>>l>>w>>h;
    Rectangular rectangular(l, w, h);
   cout<<rectangular.CalVolume()<<endl;
    return 0;
}