Calculate Circle Area using Java Example

    /*

            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

    */