using System;

///Practical functional programing in C#

//functional programming in modern Web Application development using Asp.Net Core and 

//Domain Driven Design with the language-extfunctional library in C#

//https://leanpub.com/practical-functional-CSharp                   

public class Program

{ 

        public static void Main()

    {

​

                string GetShapeDescription1(Shape shape) =>

                    shape switch

                    {

                        Rectangle { Height: var h, Width: var w } => $"Found {h }x {w} rectangle",

                        Circle { Radius: var r } => $"found a circle with radius {r}",

                    };

​

​

                Shape shape = new Rectangle

                {

                    Width = 100,

                    Height = 100,

                };

​

                var description = GetShapeDescription1(shape);

​

        Console.WriteLine(description);

    }

  abstract class Shape { }

        class Rectangle : Shape

        {

            public int Width { get; set; }

            public int Height { get; set; }

        }

​

        class Circle : Shape

        {

            public int Radius { get; set; }

        }

​

}