using System;

abstract class Shape

{

    public abstract double GetArea();

        Square s = new Square(3.5);

        Circle c = new Circle(2.0);

        }

​

class Square : Shape

{

private double side;

public Square (double s)

{

side = s;

}

public override double GetArea (); 

​

    Console.WriteLine("Area of Square = {0}");

return(3.5*side);

}

​

​

class Cicle : Shape

{

public double radius;

public Circle (double r)

{

radius = r;

}

public override double GetArea ()

{

    Console.WriteLine("Area of Circle = {0}");

return(1.0*radius); 

}

}

​

​

​

​

​