求助：请高手帮忙用JAVA程序做一个计算器~

作者&投稿：苑哲（若有异议请与网页底部的电邮联系）

(1)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Calculator extends JFrame {

private Container container;
private GridBagLayout layout;
private GridBagConstraints constraints;
private JTextField displayField;//计算结果显示区
private String lastCommand;//保存+,-,*,/,=命令
private double result;//保存计算结果
private boolean start;//判断是否为数字的开始

public Calculator() {

super("Calculator");
container=getContentPane();
layout=new GridBagLayout();
container.setLayout(layout);
constraints=new GridBagConstraints();
start=true;
result=0;
lastCommand = "=";
displayField=new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx=0;
constraints.gridy=0;
constraints.gridwidth=4;
constraints.gridheight=1;
constraints.fill=GridBagConstraints.BOTH;
constraints.weightx=100;
constraints.weighty=100;
layout.setConstraints(displayField,constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
addButton("Backspace",0,1,2,1,insert);
addButton("CE",2,1,1,1,insert);
addButton("C",3,1,1,1,insert);
addButton("7",0,2,1,1,insert);
addButton("8",1,2,1,1,insert);
addButton("9",2,2,1,1,insert);
addButton("/",3,2,1,1,command);
addButton("4",0,3,1,1,insert);
addButton("5",1,3,1,1,insert);
addButton("6",2,3,1,1,insert);
addButton("*",3,3,1,1,command);
addButton("1",0,4,1,1,insert);
addButton("2",1,4,1,1,insert);
addButton("3",2,4,1,1,insert);
addButton("-",3,4,1,1,command);
addButton("0",0,5,1,1,insert);
addButton("+/-",1,5,1,1,insert);//只显示"-"号,"+"没有实用价值
addButton(".",2,5,1,1,insert);
addButton("+",3,5,1,1,command);
addButton("=",0,6,4,1,command);
setSize(300,300);
setVisible(true);

}

private void addButton(String label,int row,int column,int with,int height,ActionListener listener) {

JButton button=new JButton(label);
constraints.gridx=row;
constraints.gridy=column;
constraints.gridwidth=with;
constraints.gridheight=height;
constraints.fill=GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button,constraints);
container.add(button);
}

private class InsertAction implements ActionListener {

public void actionPerformed(ActionEvent event) {

String input=event.getActionCommand();
if (start) {
displayField.setText("");
start=false;
if(input.equals("+/-"))
displayField.setText(displayField.getText()+"-");
}

if(!input.equals("+/-")) {
if(input.equals("Backspace")) {
String str=displayField.getText();
if(str.length()>0)
displayField.setText(str.substring(0,str.length()-1));
}else if(input.equals("CE")||input.equals("C")) {
displayField.setText("0");
start=true;
}else
displayField.setText(displayField.getText()+input);
}
}
}

private class CommandAction implements ActionListener {

public void actionPerformed(ActionEvent evt) {
String command=evt.getActionCommand();
if(start) {
lastCommand=command;
}else {
calculate(Double.parseDouble(displayField.getText()));
lastCommand=command;
start=true;
}
}
}

public void calculate(double x) {
if (lastCommand.equals("+")) result+= x;
else if (lastCommand.equals("-")) result-=x;
else if (lastCommand.equals("*")) result*=x;
else if (lastCommand.equals("/")) result/=x;
else if (lastCommand.equals("=")) result=x;
displayField.setText(""+ result);
}

public static void main(String []args) {
Calculator calculator=new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

}

(2)

真是爽阿，两个要这个代码的
看看我写得把，还不错，楼主给我追加点分吧
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Calculator extends JFrame {

private Container container;
private GridBagLayout layout;
private GridBagConstraints constraints;
private JTextField displayField;//计算结果显示区
private String lastCommand;//保存+,-,*,/,=命令
private double result;//保存计算结果
private boolean start;//判断是否为数字的开始

public Calculator() {

super("Calculator");
container=getContentPane();
layout=new GridBagLayout();
container.setLayout(layout);
constraints=new GridBagConstraints();
start=true;
result=0;
lastCommand = "=";
displayField=new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx=0;
constraints.gridy=0;
constraints.gridwidth=4;
constraints.gridheight=1;
constraints.fill=GridBagConstraints.BOTH;
constraints.weightx=100;
constraints.weighty=100;
layout.setConstraints(displayField,constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
addButton("Backspace",0,1,2,1,insert);
addButton("CE",2,1,1,1,insert);
addButton("C",3,1,1,1,insert);
addButton("7",0,2,1,1,insert);
addButton("8",1,2,1,1,insert);
addButton("9",2,2,1,1,insert);
addButton("/",3,2,1,1,command);
addButton("4",0,3,1,1,insert);
addButton("5",1,3,1,1,insert);
addButton("6",2,3,1,1,insert);
addButton("*",3,3,1,1,command);
addButton("1",0,4,1,1,insert);
addButton("2",1,4,1,1,insert);
addButton("3",2,4,1,1,insert);
addButton("-",3,4,1,1,command);
addButton("0",0,5,1,1,insert);
addButton("+/-",1,5,1,1,insert);//只显示"-"号,"+"没有实用价值
addButton(".",2,5,1,1,insert);
addButton("+",3,5,1,1,command);
addButton("=",0,6,4,1,command);
setSize(300,300);
setVisible(true);

}

private void addButton(String label,int row,int column,int with,int height,ActionListener listener) {

JButton button=new JButton(label);
constraints.gridx=row;
constraints.gridy=column;
constraints.gridwidth=with;
constraints.gridheight=height;
constraints.fill=GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button,constraints);
container.add(button);
}

private class InsertAction implements ActionListener {

public void actionPerformed(ActionEvent event) {

String input=event.getActionCommand();
if (start) {
displayField.setText("");
start=false;
if(input.equals("+/-"))
displayField.setText(displayField.getText()+"-");
}

if(!input.equals("+/-")) {
if(input.equals("Backspace")) {
String str=displayField.getText();
if(str.length()>0)
displayField.setText(str.substring(0,str.length()-1));
}else if(input.equals("CE")||input.equals("C")) {
displayField.setText("0");
start=true;
}else
displayField.setText(displayField.getText()+input);
}
}
}

private class CommandAction implements ActionListener {

public void actionPerformed(ActionEvent evt) {
String command=evt.getActionCommand();
if(start) {
lastCommand=command;
}else {
calculate(Double.parseDouble(displayField.getText()));
lastCommand=command;
start=true;
}
}
}

public void calculate(double x) {
if (lastCommand.equals("+")) result+= x;
else if (lastCommand.equals("-")) result-=x;
else if (lastCommand.equals("*")) result*=x;
else if (lastCommand.equals("/")) result/=x;
else if (lastCommand.equals("=")) result=x;
displayField.setText(""+ result);
}

public static void main(String []args) {
Calculator calculator=new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

}

(3)

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
class Counter extends WindowAdapter
{
static JFrame f=new JFrame("计算器");
static JTextField text1=new JTextField("0.");
static String source="";
static String cal="";
static String object="";
static boolean flag=false;
static boolean flag1=true;
static boolean flag2=false;
public void init()
{
try
{
Container c=f.getContentPane();
JPanel pan1=new JPanel();
JButton b1=new JButton("1");
JButton b2=new JButton("2");
JButton b3=new JButton("3");
JButton b4=new JButton("4");
JButton b5=new JButton("5");
JButton b6=new JButton("6");
JButton b7=new JButton("7");
JButton b8=new JButton("8");
JButton b9=new JButton("9");
JButton b0=new JButton("0");
JButton b11=new JButton("+");
JButton b12=new JButton("-");
JButton b13=new JButton("*");
JButton b14=new JButton("/");
JButton b15=new JButton(".");
JButton b16=new JButton("=");
JButton bclar=new JButton("清零");
text1.setHorizontalAlignment(JTextField.RIGHT);
c.add(text1,"North");
c.add(pan1);
A aa=new A();
Result re=new Result();
Opertion op=new Opertion();
Clar cl=new Clar();
b1.addActionListener(aa);
b2.addActionListener(aa);
b3.addActionListener(aa);
b4.addActionListener(aa);
b5.addActionListener(aa);
b6.addActionListener(aa);
b7.addActionListener(aa);
b8.addActionListener(aa);
b9.addActionListener(aa);
b0.addActionListener(aa);
b11.addActionListener(op);
b12.addActionListener(op);
b13.addActionListener(op);
b14.addActionListener(op);
b16.addActionListener(re);
b15.addActionListener(aa);
bclar.addActionListener(cl);
pan1.add(b1);
pan1.add(b2);
pan1.add(b3);
pan1.add(b11);
pan1.add(b4);
pan1.add(b5);
pan1.add(b6);
pan1.add(b12);
pan1.add(b7);
pan1.add(b8);
pan1.add(b9);
pan1.add(b13);
pan1.add(b0);
pan1.add(b15);
pan1.add(b16);
pan1.add(b14);
pan1.add(bclar);
f.setSize(200,220);
f.setVisible(true);
}
catch(Exception e)
{
System.out.println(e.getMessage());
}

}
class A implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String a=text1.getText();
String s=e.getActionCommand();
if(a.equals("0.")||a.equals("+")||a.equals("-")||a.equals("*")||a.equals("/"))
text1.setText(s);
else {
if(flag2)
{
text1.setText(s);
flag2=false;
}
else
text1.setText(a+s);

}
}
}
class Opertion implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
cal=e.getActionCommand();
if(flag1==true)
source=text1.getText();
text1.setText(cal);
flag1=false;
flag=true;
}
}
class Result implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
double num1;
num1=Double.parseDouble(source);
object=text1.getText();
double num2;
num2=Double.parseDouble(object);
double result=0;
if(cal.equals("+"))
result=num1+num2;
if(cal.equals("-"))
result=num1-num2;
if(cal.equals("*"))
result=num1*num2;
if(cal.equals("/"))
if(num2==0)
text1.setText("除数不能为0");
else
result=num1/num2;
String s1=Double.toString(result);
text1.setText(s1);
flag1=true;
flag2=true;
}
}
class Clar implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
text1.setText("0.");
}
}

public static void main(String[] args)
{
Counter count=new Counter();
count.init();
}

public void windowClosing(WindowEvent e){
System.exit(1);
}
public void windowOpened(WindowEvent e){}
public void windowIconified(WindowEvent e){}
public void windowDeiconified(WindowEvent e){}
public void windowClosed(WindowEvent e){}
public void windowActivated(WindowEvent e){}
public void windowDeactivated(WindowEvent e){}
}

http://www.sohozu.com/2005/4-19/19040518160-5.Html呵呵,借了个连接

java一个编写简单的计算器的一个程序问题得按要求做呜呜呜~

你是哪里不明白······格式不对弹警告框？还是计算的时候算法有问题？

我只看了public void actionPerformed(ActionEvent e)上面的一段，发现的问题是：
1、Frame f和Panel p分别添加了10个Button，重复，应该只在Panel上面添加；
2、在添加Button的时候，你的代码如下：
for (int i=0;i<16;i++){
p.add(new Button(s[i]));
new Button(s[i]).addActionListener(this);
}
这样的话，你在Panel上面添加的Button是没有注册事件监听的。
应为这样：
for (int i=0;i<16;i++){
Button btn = new Button(s[i]);

btn.addActionListener(this);

p.add(btn);
}
3、代码结构混乱，不易阅读，建议把变量声明放到开头，添加注释。

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求助：请高手帮忙用JAVA程序做一个计算器~

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