用Java写的计算器
package com.wenbo.myprogrem.day15;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Caculator implements ActionListener{
String result="0";
String oper="+";//运算符
Double res;
StringBuilder sb=new StringBuilder();
JTextField jtf = new JTextField(10);
private boolean append=false;
public Caculator(){
JFrame jf = new JFrame("简易计算器");
JPanel jp = new JPanel();
jp.setLayout(new GridLayout(5,4));
String[] lab = {"Backs","CE","E","+","7","8","9",
"-","4","5","6","*","1","2","3",
"/","0","+/-",".","="};
for (int i=0; i <20; i++) {
JButton jb = new JButton(lab[i]);
jb.addActionListener(this);//给每个按钮注册监听器
jp.add(jb);
}
jf.setResizable(false);
jf.add(jp);
jtf.addActionListener(this);
jf.add(jtf,BorderLayout.NORTH);
jf.setSize(320,240);//像素
jf.setLocation(300,200);//设置出现位置
jf.setVisible(true);
jf.setDefaultCloseOperation(//设置X
JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e) {
String comm=e.getActionCommand();//获得按钮上的文字
System.out.println(comm);
if("0123456789".indexOf(comm)!=-1){
if(append){//追加，刚开始是false按完数字�
简单的说，内部（inner）类指那些类定义代码被置于其它类定义中的类；而对于一般的、类定义代码不嵌套在其它类定义中的类，称为顶层（top-level）类。对于一个内部类，包含其定义代码的类称为它的外部（outer）类。
1 Static member class（静态成员类）
类声明中包含“static”关键字的内部类。如以� ......
