1  // Applet to calculate sphere volumes
  2  
  3  import java.awt.*;
  4  import java.awt.event.*;
  5  
  6  public class VolumeApplet extends java.applet.Applet
  7  		implements ActionListener
  8  {
  9     int radius;
 10     double volume;
 11     Label prompt1,prompt2;
 12     TextField input, output;
 13  
 14     public void init()
 15     {
 16        prompt1 = new Label("Enter the radius of a sphere:  ");
 17        add(prompt1);
 18  
 19        input = new TextField(10);
 20        input.addActionListener(this);
 21        add(input);
 22  
 23        prompt2 = new Label("The volume of the sphere is:  ");
 24        add(prompt2);
 25  
 26        output = new TextField(30);
 27        add(output);
 28     }
 29  
 30  
 31     public void actionPerformed (ActionEvent e)
 32     {
 33        Double vol;
 34  
 35        radius = Integer.parseInt (input.getText() );
 36  
 37        volume = (4.0/3.0) * Math.PI * Math.pow(radius,3);
 38        vol = new Double(volume);      
 39        output.setText(vol.toString());
 40     }
 41      
 42  }
 43        
 44  
 45