using System;

namespace ConsoleApplication13

{

       interface Ishape

    {

        double CalculateArea();

    }

     class Circle:Ishape

    {

        private double radius;

        public Circle(double radius)

        {

            this.radius = radius;

        }

        public double CalculateArea()

        {

            return Math.PI * radius * radius;

        }

    }

    class Rectangle : Ishape

    {

        private double length;

         private double width;

         public Rectangle(double length, double width)

        {

            this.length = length;

            this.width = width;

        }

        public double CalculateArea()

        {

            return length * width;

        }

    }

  public  class Program

    {

     public   static void Main(string[] args)

        {

            Circle circle = new Circle(5);

            Rectangle rectangle = new Rectangle(4, 6);

​

            Ishape shape1 = GetShape("circle");

            Ishape shape2 = GetShape("rectangle");

            Console.WriteLine(shape1.CalculateArea());

            Console.WriteLine(shape2.CalculateArea());

        }

    static Ishape GetShape(String type)

        {

            if(type.ToLower()=="circle")

            {

                return new Circle(5);

            }

            else if (type.ToLower()=="rectangle")

            {

                return new Rectangle(4,6);

            }

            else{

                throw new ArgumentException("Invalid Shape Type");

            }

        }

    }

}

​

​

​

​