using System;

​

public class DrawingObject

{

    public virtual void Draw()

    {

        Console.WriteLine("I'm just a generic drawing object.");

    }

}

​

public class Line : DrawingObject

{

    public override void Draw()

    {

        Console.WriteLine("I'm a Line.");

    }

}

​

public class Circle : DrawingObject

{

    public override void Draw()

    {

        Console.WriteLine("I'm a Circle.");

    }

}

​

public class Square : DrawingObject

{

    public override void Draw()

    {

        Console.WriteLine("I'm a Square.");

    }

}

public class DrawDemo

{

    public static int Main( )

    {

        DrawingObject[] dObj = new DrawingObject[4];

​

        dObj[0] = new Line();

        dObj[1] = new Circle();

        dObj[2] = new Square();

        dObj[3] = new DrawingObject();

​

        foreach (DrawingObject drawObj in dObj)

        {

            drawObj.Draw();

        }

​

        return 0;

    }

}