Chapter 3: Sample program:Compute Area and Circumference

/*Chapter 3: Sample program:Compute Area and Circumference
*File: Ch3Circle.java
*/

import javax.swing.*;
class Ch3Circle{
public static void main( String[] args){

     final double PI = 3.14.159;

    String radiusStr;
    double radius, area, circumference;

      radiusStr = JoptionPane.showInputDialog(null, "Enter radius:");
   radius= Double.parseDouble(radiusStr);

//compute area and circumference

area= PI * radius * radius;
circumference = 2.0 * PI * radius;

JOptionPane.showMessageDialog(null, "Given Radius:" +radius + "\n"
                                                          + "Area:" +area+"\n"
                                                                 +"Circumference:"+circumference);
        }
}