Java Source - Calculate Circle Perimeter

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/*
 Calculate Circle Perimeter using Java Example
 This Calculate Circle Perimeter using Java Example shows how to calculate
 Perimeter of circle using it's radius.
 */

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

public class CalculateCirclePerimeterExample {

    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);
    }
}

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/*

Output of Calculate Circle Perimeter using Java Example would be

Please enter radius of a circle

19

Perimeter of a circle is 119.38052083641213

*/

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