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;

public class Hello
{
    public static void Main()
    {
        double num;
        string s;

        while((s = Console.ReadLine() ) != null)
        {
            if (s == "0") break;
            num = double.Parse(s);
            Console.WriteLine("{0:0.000000} {1:0.000000}", num * num * Math.PI, num * 2 * Math.PI);
        }
    }
}