Java Code to Find the Perimeter

Perimeter of a Circle Using Java

A Java program to accept the radius of a Circle from user and calculate the Perimeter.

//A small java program to calculate the Perimeter of a circle

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class CirclePerimeter {

        public static void main(String[] args) {
               
                int radius = 0;
                System.out.println("Please enter radius of a circle");
               
                try
                {
                        //get the radius from console
                        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                        radius = Integer.parseInt(br.readLine());
                }
                //if invalid value was entered
                catch(NumberFormatException ne)
                {
                        System.out.println("Invalid radius value" + ne);
                        System.exit(0);
                }
                catch(IOException ioe)
                {
                        System.out.println("IO Error :" + ioe);
                        System.exit(0);
                }
               
                /*
                 * Perimeter of a circle is
                 * 2 * pi * r
                 * where r is a radius of a circle.
                 */
               
                //NOTE : use Math.PI constant to get value of pi
                double perimeter = 2 * Math.PI * radius;
               
                System.out.println("Perimeter of a circle is " + perimeter);
        }
}

Output:

Please enter radius of a circle
12
Perimeter of a circle is 75.39822368615503