using System;

    namespace ShapeLibrary

{

    public class Circle

    {

        // Data Member: Radius of the circle

        public double Radius { get; set; }

​

        // Default constructor

        public Circle() { }

​

        // Parameterized constructor

        public Circle(double radius)

        {

            Radius = radius;

        }

​

        // Method to calculate the area of the circle

        public double CalculateArea()

        {

            return Math.PI * Radius * Radius;

        }

    }

}

​