こんなかんじの電卓に機能をもたせたいです。＋−×÷だけで小数点、変数いりません
private Label label;
private TextField textField;
private Button button[];
private Panel panel1,panel2;

public void init(){
panel1 = new Panel();
panel1.setLayout(new BorderLayout(2, 2));
panel2 = new Panel();
panel2.setLayout(new GridLayout(4, 4, 2, 2));

label = new Label();
label.setText("Calculator");
panel1.add(label, BorderLayout.CENTER);

textField = new TextField(40);
panel1.add(textField, BorderLayout.SOUTH);

button = new Button[17];

button[1] = new Button("7");
button[1].addActionListener(this);
panel2.add(button[1]);
button[2] = new Button("8");
button[2].addActionListener(this);
panel2.add(button[2]);
button[3] = new Button("9");
button[3].addActionListener(this);
panel2.add(button[3]);
以下長いので省略