using System;

class Shape

    {

        public Shape()

        {

            System.Console.WriteLine("Shape");

        }

        public virtual void draw()

        {

            System.Console.WriteLine("Drawing Shape");

        }

    }

    class Circle : Shape

    {

        int r;

        public Circle()

        {

            System.Console.WriteLine("Circle");

        }

        public override void draw()

        {

            System.Console.WriteLine("Drawing Circle");

        }

    }

    class Triangle : Shape

    {

        public int a,b,c;

        public Triangle()

        {

            System.Console.WriteLine("Triangle");

        }

        public override void draw()

        {

            System.Console.WriteLine("Drawing Triangle");

        }

    }

    public class InheritanceSample

    {

      public  static void Main()

        {

          /*

            C# makes virtual functions definition perfect and it requires the use of virtual and override keywords. 

            You need to use virual keyword in base class and override keyword in derived classes.

            When writing derived classes C++ and C# uses ":" between derived class and base class. Java uses extends keyword instead of :

            There are 3 classes given on this example. 

            Shape is a base class and Circle and Triangle are the classes derived from the base class Shape. 

            The base class Shape* is used to access all two dervied class functions.

          */

            Shape [] objects = { new Shape(),

                            new Circle(),

                            new Triangle()

            };

            System.Console.WriteLine("\n\nNow Drawing Objects\n");

            for(int i = 0; i < 3; i++)

                objects[i].draw(); // This line explains the concept of polymorphism

            System.Console.WriteLine("\n");

        }

    }