java小實驗

package Second;import java.awt.*;import javax.swing.*;import java.math.*;import java.awt.event.*;public class test1 implements ActionListener{/** * @param args */  public JTextField s=new JTextField(13);  public JTextField s1=new JTextField(13);  public JLabel l1=new JLabel("平方");  public JLabel l2=new JLabel("立方");  public JLabel l3=new JLabel(" 四次方");  public JButton b1=new JButton("平方結果");  public JButton b2=new JButton("立方結果");  public JButton b3=new JButton("四次方根");void display(){    JPanel panel=new JPanel(new GridLayout(4,2));  JFrame jf=new JFrame("測試程式");  jf.setSize(300,200);  jf.setContentPane(panel);  jf.setVisible(true);  jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  jf.setResizable(false);  panel.add(s);  panel.add(s1);  panel.add(l1);  panel.add(b1);  panel.add(l2);  panel.add(b2);  panel.add(l3);  panel.add(b3);  b1.addActionListener(this);  b2.addActionListener(this);  b3.addActionListener(this);}public void actionPerformed(ActionEvent e){if(e.getSource()==b1){ double a=Double.parseDouble(s.getText()); a=a*a; s1.setText(""+a);}else if(e.getSource()==b2){ double a=Double.parseDouble(s.getText()); a=a*a*a; s1.setText(""+a);}else if(e.getSource()==b3){double a=Double.parseDouble(s.getText());a=a*a*a*a;s1.setText(""+a);}}public static void main(String[] args) {// TODO Auto-generated method stub          test1 m=new test1();          m.display();}}