Calculator Applet using AWT Java

SimpleCalc.java

import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;


public class SimpleCalc extends Applet{

	private Label xInputLabel,yInputLabel;
	private Label statusLabel;
	private Panel xInputPanel;
	private Panel yInputPanel,operations;
	private Label msgLabel;
	private TextField xInputText,yInputText;
	private Button add,sub,mul,div;

	public void init(){
		prepareGUI();
	}


	private void prepareGUI(){

		CalculateActionListener ce = new CalculateActionListener();

		xInputLabel = new Label("X = ");
		xInputLabel.setAlignment(Label.RIGHT);

		yInputLabel = new Label("Y = ");
		yInputLabel.setAlignment(Label.RIGHT);

		msgLabel = new Label("X + Y = 0");
		msgLabel.setAlignment(Label.CENTER);

		xInputText = new TextField("0");
		yInputText = new TextField("0");

		add = new Button("+");
		sub = new Button("-");
		mul = new Button("*");
		div = new Button("/");

		add.addActionListener(ce);
		sub.addActionListener(ce);
		mul.addActionListener(ce);
		div.addActionListener(ce);


		xInputPanel = new Panel();
		xInputPanel.setLayout(new GridLayout(1,2));

		yInputPanel = new Panel();
		yInputPanel.setLayout(new GridLayout(1,2));

		operations = new Panel();
		operations.setLayout(new GridLayout(1,4));

		xInputPanel.add(xInputLabel);
		xInputPanel.add(xInputText);

		yInputPanel.add(yInputLabel);
		yInputPanel.add(yInputText);
		
		operations.add(add);
		operations.add(sub);
		operations.add(mul);
		operations.add(div);

		setLayout(new GridLayout(4,1));

		add(xInputPanel);
		add(yInputPanel);
		add(operations);
		add(msgLabel);



	}

	private class CalculateActionListener implements ActionListener{


		public void actionPerformed(ActionEvent e){
				double x = Double.parseDouble(xInputText.getText());
				double y = Double.parseDouble(yInputText.getText());
				byte flag = 0;

				switch(e.getActionCommand()){
					case "+": 
						x +=y;
						break;
					case "-":
						x-=y;
						break;
					case "*":
						x*=y;
						break;
					case "/":
						if(y==0) flag = 1;
						else
							x /= y;
						break;
					default: flag = 1;
				}

				if (flag == 0){
					msgLabel.setText("X " + e.getActionCommand() + " Y =" + x);
				}else{
					msgLabel.setText("Error..Check the input values");
				}
			}
	}


}

/*
<applet code = "SimpleCalc" width = 400 height = 400> </applet>
*/