import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
/**
 * A two button Applet, can add or subtract two numbers
 *
 * @author Mr J
 * @version 241103
 */
public class AddSub extends Applet implements ActionListener
{
	// two text fields for the numbers
	private TextField number1 = new TextField(20);
	private TextField number2 = new TextField(20);
	// two buttons for the add/subtract options
	private Button add = new Button("+");
	private Button sub = new Button("-");
	// Label for the answer
	private Label answer = new Label("The answer will appear here");

	/** 
	 * Add the objects to the Applet
	 */
	public void init()
	{
        add(number1);
        add(number2);
        add(add);
        add(sub);
        add(answer);
        // Causes button presses to be detected
        add.addActionListener(this);
        sub.addActionListener(this);
	}
	/** 
	 * When an event occurs on an object with an ActionListener attached, this
	 * method is carried out.  
	 * 
	 * @param e carries details about the event that occurred
	 */
	  public void actionPerformed(ActionEvent e)
	  {
	    int total = 0;
	    int n1, n2;
	    // convert the Strings from the TextFields to ints 
	    n1 = Integer.parseInt(number1.getText());
	    n2 = Integer.parseInt(number2.getText());
	    
	    // check which button was pressed
	    if (e.getSource()== add)
	    {
	        total = n1 + n2;
	    }
	    else // must have been sub
	    {
	        total = n1 - n2;
	    }
	    // put answer
	    answer.setText("" + total);
	}
}