Calculate Circle Perimeter Using Java Example

In the Following example PerimeterofCircleExample shows how to Calculate Perimeter of Circle using 2*pi*r. where r is a radius of a circle.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class PerimeterofCircleExample { // Declaring class name as PerimeterofCircleExample
 
public static void main(String[] args) {
               
 int r = 0;  // r for radius of circle
System.out.print("Please enter the radius value r :");
try
{ 
 //Obtaining the keyboard input with BufferedReader
BufferedReader Buffer= new BufferedReader(new InputStreamReader(System.in));
 r = Integer.parseInt(Buffer.readLine());
/* Math.PI = 3.14 is Math constant to get value of pi
    Perform Calculations and Display Result
    calculate the perimeter of circle that is PerimeterofCircle = 2 *pi*r
*/ 
 double PerimeterofCircle = 2 * Math.PI * r;
System.out.println("The Perimeter of circle is " + PerimeterofCircle);
}
catch(Exception e)
                     {
                                 System.out.println("Input Error : "+e);                       
                       } 
        }
}