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;

namespace ITP1_4_B
{
    class Program
    {
        static void Main(string[] args)
        {
            //半径をinput
            string str = Console.ReadLine();
            double r = double.Parse(str);

            if (r <= 0 && 10000 <= r)
                Environment.Exit(0);

            double area, circumference;

            area = r * r * 3.14159265358979323846; //面積計算

            circumference = r * 2 * 3.14159265358979323846; //周計算

            Console.WriteLine("{0,-8:F6} {1,-8:F6}",area,circumference);
        }
    }
}