/*

Calculate Circle Area using Java Example

This Calculate Circle Area using Java Example shows how to calculate

area of circle using it’s radius.

*/

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class CalculateCircleAreaExample {

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);

}

/*

* Area of a circle is

* pi * r * r

* where r is a radius of a circle.

*/

//NOTE : use Math.PI constant to get value of pi

double area = Math.PI * radius * radius;

System.out.println(“Area of a circle is ” + area);

}

}

/*

Output of Calculate Circle Area using Java Example would be

Please enter radius of a circle

19

Area of a circle is 1134.1149479459152

*/