简单计算器代码

 package computer;
    import java.awt.*;

import java.awt.event.*;



import javax.swing.*;

import javax.xml.bind.DatatypeConverter;


import  java.math.*;

public class computer extends JFrame{


public JTextField txtb=new JTextField(25);

public JButton button0;

public JButton button1;

public JButton button2;

public JButton button3;

public JButton button4;

public JButton button5;

public JButton button6;

public JButton button7;

public JButton button8;

public JButton button9;

public JButton d;

public JButton p;

public JButton g;

public JButton bak;

public JButton add;

public JButton redues;

public JButton cheng;

public JButton chu;

public JButton equal;

public JButton point;

double a,b,c;