Simple Applet-Add Program in java

import java.awt.*; import java.awt.event.*; import java.applet.*; import java.io.*; /* */ public class ca extends Applet { TextField tx0=new TextField(10); TextField tx1=new TextField(10); TextField tx2=new TextField(10); Button B0=new Button("Add"); String str; double x,y,z; public void start() { add(new Label("Enter a text:\r\n")); add(tx0); add(new Label("Enter a text:\r\n")); add(tx1); B0.addActionListener(new CAL()); add(B0); add(tx2); //tx2.setVisible(false); } class CAL implements ActionListener { public void actionPerformed(ActionEvent e) { str=tx0.getText(); x=Double.parseDouble(str); str=tx1.getText(); y=Double.parseDouble(str); z=x+y; str=String.valueOf(z); tx2.setText(str); } } public void actionPerformed(ActionEvent ae) { repaint(); } } OutPut: