Exercise Seven 

import java.awt.*;

public class Calculator extends Panel
  {

  public TextField displayField;
  public Panel     buttonPanel;
  public Button    oneButton, twoButton, threeButton,
                   fourButton, fiveButton, sixButton,
                   sevenButton, eightButton, nineButton,
                   zeroButton, addButton, subtractButton,
                   multiplyButton, divideButton, 
                   equalsButton;

  public Calculator()
    {
    setLayout(new BorderLayout());
    displayField = new TextField();
    add("North", displayField);

    buttonPanel = new Panel();
    buttonPanel.setLayout(new GridLayout(5,3));

    oneButton = new Button("1");
    twoButton = new Button("2");
    threeButton = new Button("3");
    fourButton = new Button("4");
    fiveButton = new Button("5");
    sixButton = new Button("6");
    sevenButton = new Button("7");
    eightButton = new Button("8");
    nineButton = new Button("9");
    zeroButton = new Button("0");
    addButton = new Button("+");
    subtractButton = new Button("-");
    multiplyButton = new Button("*");
    divideButton = new Button("/");
    equalsButton = new Button("=");

    buttonPanel.add(oneButton);    
    buttonPanel.add(twoButton); 
    buttonPanel.add(addButton); 
    buttonPanel.add(threeButton); 
    buttonPanel.add(fourButton); 
    buttonPanel.add(subtractButton); 
    buttonPanel.add(fiveButton); 
    buttonPanel.add(sixButton); 
    buttonPanel.add(multiplyButton); 
    buttonPanel.add(sevenButton); 
    buttonPanel.add(eightButton); 
    buttonPanel.add(divideButton); 
    buttonPanel.add(nineButton); 
    buttonPanel.add(zeroButton); 
    buttonPanel.add(equalsButton); 
  
    add("Center", buttonPanel);
    }

  public static void main(String[] args)
    {
    Frame baseFrame = new Frame();
    Calculator c = new Calculator();
    baseFrame.add("Center", c);
    baseFrame.reshape(10,10,200,200);
    baseFrame.setTitle("Calculator Example");
    baseFrame.show();
    }
  }