C# Abstract class and overriding example

Program

using System;

namespace AbstractClass

{

    abstract class Shape

    {

        //protected string _name; will be implemented automatically

        protected string name { get; set; }

        public Shape(string name)

        {

            this.name = name;

        }

        public abstract float CalculateArea();

    }

    class Circle: Shape

    {

        //int _radius; will be implemented automatically

        public int radius { get; set; }

        public Circle(string name, int radius):base(name)

        {

            this.radius = radius;

        }

        public override float CalculateArea()

        {

            return 3.14f * (radius * radius);

        }

    }

    class Square: Shape

    {

        //int _side; will be implemented automatically

        public int side { get; set; }

        public Square(string name, int side): base(name)

        {

            this.side = side;

        }

        public override float CalculateArea()

        {

            return side * side;

        }

    }

    class Rectangle: Shape

    {

        //int _length,_breadth; will be implemented automatically

        public int length { get; set; }

        public int breadth { get; set; }

        public Rectangle(string name, int length, int breadth): base(name)

        {

            this.length = length;

            this.breadth = breadth;

        }

        public override float CalculateArea()

        {

            return length * breadth;

        }

    }

    class Program

    {

        static void Main(string[] args)

        {

            Console.WriteLine("Circle\nSquare\nRectangle\n

                                       Enter the shape name");

            string ShapeName = Console.ReadLine().ToLower();

            switch (ShapeName)

            {

                case "circle":

                    Console.WriteLine("Enter the radius");

                    int radius = int.Parse(Console.ReadLine());

                    Circle refCir = new Circle("Circle", radius);

                    Console.WriteLine(refCir.CalculateArea()

                                                .ToString(".00"));

                     break;

                case "square":

                    Console.WriteLine("Enter the side");

                    int side = int.Parse(Console.ReadLine());

                    Square refSqr = new Square("Square", side);

                    Console.WriteLine(refSqr.CalculateArea()

                                                 .ToString(".00"));

                    break;

                case "rectangle":

                    Console.WriteLine("Enter the length");

                    int len = int.Parse(Console.ReadLine());

                    Console.WriteLine("Enter the breadth");

                    int bth = int.Parse(Console.ReadLine());

                    Rectangle refRect = new Rectangle("Rectangle", len,                                                                         bth);

                    Console.WriteLine(refRect.CalculateArea()

                                                .ToString(".00"));

                    break;

                default:

                    Console.WriteLine("Invalid input please check                                                                    spelling");

                    break;

            }

            Console.ReadKey();

        }

    }

}

Output 1

Circle
Square
Rectangle
Enter the shape name
circle
Enter the radius
25
1962.50

Output 2
Circle
Square
Rectangle
Enter the shape name
square
Enter the side
23
529.00

Output 3
Circle
Square
Rectangle
Enter the shape name
rectangle
Enter the length
45
Enter the breadth
60
2700.00