Problem:
Circle

Write a program which calculates the area and circumference of a circle for given radius r.

Input

A real number r is given.

Output

Print the area and circumference of the circle in a line. Put a single space between them. The output should not contain an absolute error greater than 10-5.

Constraints

0 < r < 10000

Sample Input 1

2

Sample Output 1

12.566371 12.566371

Sample Input 2

3

Sample Output 2

28.274334 18.849556

Solution in C# (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Circle
{
    class Program
    {
        static void Main(string[] args)
        {
            string line = Console.ReadLine();
            double r = double.Parse(line);

            CalculateCircle problem = new CalculateCircle(r);

            Console.WriteLine(problem.GetArea().ToString("F6") + " " +
                problem.GetLength().ToString("F6"));
        }
    }

    /// <summary>
    /// 円に関する計算を行うクラス
    /// </summary>
    public class CalculateCircle
    {
        private double r;

        public CalculateCircle(double r)
        {
            this.r = r;
        }

        public double GetArea()
        {
            return r * r * Math.PI;
        }

        public double GetLength()
        {
            return 2 * r * Math.PI;
        }

    }
}