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;    
     
class sample14{    
    static void Main(string[] args){
        
        double r = double.Parse( Console.ReadLine());
        double area = r * r*  Math.PI;
        double around = r * 2* Math.PI;
        
        //バリデーション
        if(r<= 0 || r >= 10000 ){
            
                    Console.WriteLine("入力した値は範囲外です。");
                    Environment.Exit(0);
        } 
            
        Console.WriteLine("{0:f6} {1:f6}",area,around);
    }    
}