using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

​

namespace CircleCalculations

{

    class Program

    {

        static double circlecircum(double radius)

        {

            double pi = Math.PI;

            return (pi * radius * 2);

        }

        static double circlearea(double radius)

        {

            double pi = Math.PI;

            return (pi * radius * radius);

        }

​

        public static void Main()

        {

            double radius = 1;

            Console.ForegroundColor = ConsoleColor.Red;

            Console.WriteLine("WARNING! Only use commas for decimals (No dots allowed).");

            Console.WriteLine("Using dots or letters will result in a crash.");

            Console.WriteLine(" ");

            Console.WriteLine(" ");

            Console.ForegroundColor = ConsoleColor.White;

            Console.Write("Write the radius of the circle: ");

            radius = Convert.ToDouble(Console.ReadLine());

            Console.WriteLine(" ");

​

            Console.ForegroundColor = ConsoleColor.Green;

            Console.Write("Circle circumference: ");

            Console.ForegroundColor = ConsoleColor.White;

            Console.Write(+circlecircum(radius));

            Console.WriteLine(" ");

​

            Console.ForegroundColor = ConsoleColor.Green;

            Console.Write("Circle area: ");

            Console.ForegroundColor = ConsoleColor.White;

            Console.Write(+circlearea(radius));

            Console.WriteLine(" ");

            Console.WriteLine(" ");

            Console.WriteLine(" ");

            Console.WriteLine(" ");

            Console.WriteLine("Press any button to exit.");

            Console.ReadKey();

        }

    }

}

​