using System;

​

public class Program

{

    public static string getText(Shape obj)

    {

        RightTriangle rt = obj as RightTriangle;

        if (rt != null)

        {

            return "Side A: " + rt.sideA.ToString();

        }

​

        string retString = "";

        Circle circle = obj as Circle;

        if (circle != null)

        {

            retString += "Radius: " + circle.radius.ToString();

        }

​

        Cone cone = obj as Cone;

        if (cone != null)

        {

            retString += "Height: " + cone.height.ToString();

        }

​

        return retString;

    }

​

    public static void Main()

    {

        RightTriangle rt = new RightTriangle

        {

            sideA = 1, sideB = 2

        };

        Circle c = new Circle

        {

            radius = 1

        };

        Cone cone = new Cone

        {

            radius = 1, height = 3

        };

        Shape[] array = new Shape[3];

        array.SetValue(rt, 0);

        array.SetValue(c, 1);

        array.SetValue(cone, 2);

        Console.WriteLine("Using getText()");

        foreach (Shape p in array)

        {

            Console.WriteLine(p.GetType());

            Console.WriteLine(getText(p));

        }

​

        Console.WriteLine("Using ToString()");

        foreach (Shape p in array)

        {

            Console.WriteLine(p.GetType());

            Console.WriteLine(p.ToString());

        }

    }

}

​

public abstract class Shape

{

    public abstract double getArea();

    public override string ToString()

    {

        return "Area: " + this.getArea();

    }

}

​

public class RightTriangle : Shape

{

    public double sideA

    {

        get;

        set;

    }

​

    public double sideB

    {

        get;

        set;

    }

​

    public override double getArea()

    {

        return (this.sideA * this.sideB) / 2;

    }

​

    public override string ToString()

    {

        return "Side A: " + this.sideA + " Side B: " + sideB + " " + base.ToString();

    }

}

​

public class Circle : Shape

{

    public double radius

    {

        get;

        set;

    }

​

    public override double getArea()

    {

        return Math.Pow(this.radius, 2) * Math.PI;

    }

​

    public override string ToString()

    {

        return "Radius: " + this.radius + " " + base.ToString();

    }

}

​

public class Cone : Circle

{

    public double height

    {

        get;

        set;

    }

​

    public override double getArea()

    {

        //πr(r+sqrt(h^2+r^2))

        return Math.PI * this.radius * (this.radius + Math.Sqrt(Math.Pow(this.height, 2) + Math.Pow(this.radius, 2)));

    }

​

    public override string ToString()

    {

        return "Height : " + height + " " + base.ToString();

    }

}