请高收帮我完成Java计算器,已经完成界面了.

import javax.swing.*;
import java.awt.*;
public class Sunwy extends JFrame{
public Sunwy(){
super("袖珍计算器");
}
public static void main(String[] args){
Sunwy s1 = new Sunwy();
Container s1Container = s1.getContentPane();
s1Container.setLayout(null);
s1.setSize(250,220);
JButton jB1 = new JButton("1");
jB1.setBounds(10,40,41,30);
s1Container.add(jB1);
JButton jB2 = new JButton("2");
jB2.setBounds(50,40,41,30);
s1Container.add(jB2);
JButton jB3 = new JButton("3");
jB3.setBounds(90,40,41,30);
s1Container.add(jB3);
JButton jB4 = new JButton("4");
jB4.setBounds(10,80,41,30);
s1Container.add(jB4);
JButton jB5 = new JButton("5");
jB5.setBounds(50,80,41,30);
s1Container.add(jB5);
JButton jB6 = new JButton("6");
jB6.setBounds(90,80,41,30);

你参考一下，写个main函数再实例化这个类就行了，
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

class JFrameTest extends JFrame {
private static final long serialVersionUID = 1L;
private double d1,d2;
private int tag; //记录当前输入是第几个
private char op;

private JTextField jtf;
private String[] tits={"7","8","9","+","4","5","6","-","1","2","3","*",
"0",".","=","/"};

class opand implements ActionListener{
public void actionPerformed(ActionEvent e) {