Exercise Seven

Exercise Seven

• Ready for Homework? Your assignment is to build an interface for a calculator using buttons for each of the keys on the calculator keypad and a TextField for the display.
  

  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();
      }
    }
  
  

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