How to calculate area of a circle in c#

How to calculate area of a circle in c#


Object

Write a program which takes radius of a circle and calculates the area in case the value entered by the user is non-zero positive integer. And it displays an error message otherwise.

Code

double area;

             int   radius;

         

            Console.WriteLine("\t\tFind The Area OF Circle\n");

            Console.Write("Enter The Radius : ");

          

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

                if (radius > 0)

                {

                area = 3.14 * radius * radius;

                Console.WriteLine("Area is  : " + area);

            }

            else

            {

                Console.WriteLine(".....error......");

            }