using System;

namespace ConsoleApplication11

{

interface IShape

{

    double Area();

}

​

public class Rectangle : IShape

{

    public double Width

    {

        get;

        set;

    }

    public double Height

    {

        get;

        set;

    }

​

    public Rectangle(double width, double height)

    {

         Width = width;

         Height = height;

    }

    public double Area()

    {

        return Width * Height;

    }

}

public class Circle : IShape

{

    public double Radius

    {

        get;

        set;

    }

    public Circle(double radius)

    {

        Radius = radius;

    }

    public double Area()

    {

        return Math.PI * Radius * Radius;

    }

}

  public  class Program

    {

        static void PrintArea(IShape Shape)

        {

            Console.WriteLine(Shape.Area());

        }

public static void Main(string[] args)

        {

            Rectangle rectangle = new Rectangle(5, 10);

            Circle circle = new Circle(5);

            PrintArea(rectangle);

            PrintArea(circle);

        }

    }

}

​

​

​

​