​

​

using System;

​

public class TestClass  //Public class TestClass is defined here

{

    public class Shape  //public subclass of TestClass is defined here as Shape

    {

        public const double PI = Math.PI;  //declaration of a public double (storage parameter for the type of value parameter used (i.e. integer, decimal, boolean, float, etc...)

        protected double x, y;             //Protected can only be accessed within it's class and by derived class instances (those instances of this class would have to be initiated with the new keyword)

        public Shape()                     //Public Shape constructor (set up that if Shape were initiated without passing any variables an error wouldn't occur)

        {

        }

        public Shape(double x, double y)    //Constructor Type double x and y will be passed in referenceable by using x and y

        {

            this.x = x;                     //All this does is pull the value of x and y passed through this seconds defined constructor where Shape is initialized using two parameters)  to be clear if one parameter were used this would error out.  

            this.y = y;                     //Plus this saves those values (x and y) using the this keyword, saving the value to the instance of the particular instance of this class.

        }

​

        public virtual double Area()        //Public Method Area() returns a double value and is virtual meaning allowed to be overridden by a derived class as we will see further down.

        {

            return x * y;                   //Returning the double value

        }

    }

​

    public class Circle : Shape             //Public class Circle is a derived class of Shape above.

    {

        public Circle(double r) : base(r, 0)//Public Circle is passed a double referenced by the r, as a derived class of base (which is Shape because we derived the Circle from the Shape class) and base

        {                                   //is passed r and 0 so that line 15 public Shape(double x, double y) will give this instance of Circle a value of r for x and 0 for y

        }

​

        public override double Area()       //Then override the virtual Area Method defined on line 21 of the class Shape.  So now this Method definition is used instead of the base class's (or Shape's) Area

        {                                   //definition 

            return PI * x * x;

        }

    }

​

    class Sphere : Shape

    {

        public Sphere(double r) : base(r, 0)

        {

        }

​

        public override double Area()

        {

            return 4 * PI * x * x;

        }

    }

​

    class Cylinder : Shape

    {

        public Cylinder(double r, double h) : base(r, h)

        {

        }

​

        public override double Area()

        {

            return 2 * PI * x * x + 2 * PI * x * y;

        }

    }

​

    public static void Main()

    {

        double r = 3.0, h = 5.0;

        Shape c = new Circle(r);

        Shape s = new Sphere(r);

        Shape l = new Cylinder(r, h);

        // Display results:

        Console.WriteLine("Area of Circle   = {0:F2}", c.Area());  //{0}{1}

        Console.WriteLine("Area of Sphere   = {0:F2}", s.Area());

        Console.WriteLine("Area of Cylinder = {0:F2}{1}{2}", l.Area(),"  somethingOne", "  SomethingTwo");  //Result placement using the Console.WriteLine

        }

    }

    /*

        Output:

        Area of Circle   = 28.27

        Area of Sphere   = 113.10

        Area of Cylinder = 150.80

    */