求JAVA做的计算器完整代码，Applet实现。

下面两个可以么，是我做实验答辩时用到的！

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import java.awt.*;//AWT核心包

import java.awt.event.*;//提供事件类和监听器

public class Counter extends Frame implements ActionListener

{

TextField t=new TextField("");//文本框

Panel p1=new Panel();//new一个panel,用于存放数字键和符号键。

Panel p2=new Panel();//new一个panel,用于存放开方、平方、和清除键。

Button[] b=new Button[10];//实例化Button对象

Button bAdd=new Button("加");

Button bSub=new Button("减");

Button bMul=new Button("乘以");

Button bPoint=new Button(".");

Button bDiv=new Button("除以");

Button bEqual=new Button("等於");

Button bSqrt=new Button("开方");

Button bPow=new Button("平方");

Button bNull=new Button("清除");

String str1="";     //str1和str2存放两个输入的数

String str2="";

String operator=null;   //存放加减乘除以及开平方的符号

boolean first=true;    //检验输入的是否为第一个数

int countOper=0;    //累计输入符号的个数，连加连减等操作中会用到

double result=0.0;    //暂存结果

double num1=0.0,num2=0.0;  //两个输入的数做运算时转化为double存放

boolean error=false;   //检验除数是否为0

//构造方法

public Counter()

{

Frame s=new Frame("计算器");//创建Frame

for(int i=0;i10;i++)//利用for循环将数字键添加进p1中

{

b[i]=new Button(String.valueOf(i));

p1.add(b[i]);

b[i].setActionCommand("number");

b[i].setForeground(new Color(150,20,20));

b[i].addActionListener(this);//调用addActionListener()方法注册事件监听器

}

p1.add(bPoint);

bPoint.setActionCommand("number");

p1.add(bAdd); //数字键，符号键放置在panel的p1中

p1.add(bSub);

p1.add(bMul);

p1.add(bDiv);

p1.add(bEqual);

p2.add(bSqrt);//开方键，平方键，清除键放置在panel的p2中

p2.add(bPow);

p2.add(bNull);

bAdd.setActionCommand("oper");

bSub.setActionCommand("oper");

bMul.setActionCommand("oper");

bDiv.setActionCommand("oper");

bAdd.setForeground(Color.red);//为组键设计颜色

bSub.setForeground(Color.red);

bMul.setForeground(Color.red);

bDiv.setForeground(Color.red);

bPoint.setForeground(Color.black);

bEqual.setForeground(Color.red);

bSqrt.setForeground(Color.blue);

bPow.setForeground(Color.blue);

bNull.setForeground(Color.blue);

bAdd.addActionListener(this);//调用addActionListener()方法注册事件监听器

bSub.addActionListener(this);

bMul.addActionListener(this);

bDiv.addActionListener(this);

bPoint.addActionListener(this);

bEqual.addActionListener(this);

bSqrt.addActionListener(this);

bPow.addActionListener(this);

bNull.addActionListener(this);

p1.setLayout(new GridLayout(4,4,5,5));//网格布局管理器，把容器根据行数和列数分成同样大小的单元，

//每个单元可容纳一个组件，并且此组件会填满网格单元，不能控

//制其占据网格的大小。4、4为网格的行、列数。5、5为组建之间的

//间距

p2.setLayout(new FlowLayout());//用FlowLayout布局管理器将组建默认剧中排放，默认间隙为5个像素

add(t,"North");      //frame的north放置输入框，panel放置在center和south

add(p1,"Center");//将p1添加到Center中

add(p2,"South");//将p2添加到South中

setLocation(400,200);//设计按钮尺寸

setSize(200,200);//设计窗口尺寸

setBackground(new Color(20,200,10));//设置Frame的背景，默认为白色

setVisible(true);//设置Frame设置为可见

addWindowListener(new WindowAdapter(){   //关闭窗口功能

public void windowClosing(WindowEvent e)

{

System.exit(0);

}

});

}

//实现接口ActionListener

public void actionPerformed(ActionEvent e)

{

Button temp=(Button)e.getSource();

if(e.getActionCommand().equals("number"))

{

if(first)

{

str1=str1+temp.getLabel();

t.setText(str1);//将输入的str1显示在文本框中

}

else

{

str2=str2+temp.getLabel();

t.setText(str2);//将输入的str2显示在文本框中

}

}

else if(e.getActionCommand().equals("oper"))

{

if(str1=="")    //如果还没有输入数就点击运算符执行if

{

countOper=0;//若此，则将计数清零

first=true;

}

else

{

countOper++;//计算输入符号的个数

if(countOper1)//若输入的符号个数多余一个，则可以进行计算

{

getResult();

}

operator=temp.getLabel();//存放加减乘除以及开方、平方的符号

first=false;

}

}

else if(e.getActionCommand().equals("开方"))

{

double d=Math.sqrt(Double.parseDouble(str1));

str1=String.valueOf(d);//将计算出来的结果再次传给str1，为连计算准备

t.setText(String.valueOf(d));//将计算出来的结果传至文本框中

first=false;//置为false，即已输入第一个数

}

else if(e.getActionCommand().equals("平方"))

{

double f=Math.pow(Double.parseDouble(str1),2);

str1=String.valueOf(f);

t.setText(String.valueOf(f));

first=false;

}

else if(e.getActionCommand().equals("清除"))

{

str1="";//清空

str2="";

t.setText("");//将文本框清空

countOper=0;//将按键计数器清零

first=true;

error=false;

}

else if(e.getActionCommand().equals("等於"))

{

if((str1=="")||(str2==""))   //两个数没有输全就点击等号，执行if

{

countOper=0;//将按键计数器清零

first=true;

}

else

{

getResult();

countOper=0;

}

}

}

//运算结果的方法

public void getResult()

{

num1=Double.parseDouble(str1);

num2=Double.parseDouble(str2);

if(operator.equals("加"))

{

result=num1+num2;

}

else if(operator.equals("减"))

{

result=num1-num2;

}

else if(operator.equals("乘以"))

{

result=num1*num2;

}

else if(operator.equals("除以"))

{

if(num2==0.0)    //除数为0的处理方法

{

error=true;

}

else

{

result=num1/num2;

}

}

if(error)

{

t.setText("error");

}

else

{

t.setText(String.valueOf(result));

str1=String.valueOf(result);  //运算后把结果放入str1中，str2清空，为连加连减等操作做准备

str2="";

}

}

//主方法

public static void main(String[] args)

{

new Counter();//创建一个对象"计算器"

}

}

import   java.awt.*;

import   java.awt.event.*;

import   javax.swing.*;

class   CalculatorPanel   extends   JPanel

implements   ActionListener

{     public   CalculatorPanel()

{     setLayout(new   BorderLayout());

display   =   new   JTextField("0");

display.setEditable(false);

add(display,   "North");

JPanel   p   =   new   JPanel();

p.setLayout(new   GridLayout(4,   4));

String   buttons   =   "789/456*123-0.=+";

for   (int   i   =   0;   i      buttons.length();   i++)

addButton(p,   buttons.substring(i,   i   +   1));

add(p,   "Center");

}

private   void   addButton(Container   c,   String   s)

{     JButton   b   =   new   JButton(s);

c.add(b);

b.addActionListener(this);

}

public   void   actionPerformed(ActionEvent   evt)

{     String   s   =   evt.getActionCommand();

if   ('0'   =   s.charAt(0)      s.charAt(0)   =   '9'

||   s.equals("."))

{     if   (start)   display.setText(s);

else   display.setText(display.getText()   +   s);

start   =   false;

}

else

{     if   (start)

{     if   (s.equals("-"))

{   display.setText(s);   start   =   false;   }

else   op   =   s;

}

else

{     calculate(Double.parseDouble(display.getText()));

op   =   s;

start   =   true;

}

}

}

public   void   calculate(double   n)

{     if   (op.equals("+"))   arg   +=   n;

else   if   (op.equals("-"))   arg   -=   n;

else   if   (op.equals("*"))   arg   *=   n;

else   if   (op.equals("/"))   arg   /=   n;

else   if   (op.equals("="))   arg   =   n;

display.setText(""   +   arg);

}

private   JTextField   display;

private   double   arg   =   0;

private   String   op   =   "=";

private   boolean   start   =   true;

}

public   class   CalculatorApplet   extends   JApplet

{     public   void   init()

{     Container   contentPane   =   getContentPane();

contentPane.add(new   CalculatorPanel());

}

}

java编一个计算器的代码

界面漂亮堪比系统自带计算器，功能完美加减乘除开平方等等全部具备，还有清零按钮，小数点的使用，连加连乘功能完全参考系统官方计算器经过长期调试改进而成，马上拷贝代码拿去试试看吧，绝不后悔！

代码如下：

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.util.*;

public class Counter {

public static void main(String[] args) {

CounterFrame frame = new CounterFrame();

frame.show();

}

}

class CounterFrame extends JFrame {

public CounterFrame() {

JMenuBar menuBar = new JMenuBar();

JMenu menuFile = new JMenu();

JMenu menuFile1 = new JMenu();

JMenu menuFile2 = new JMenu();

JMenu menuFile3 = new JMenu();

JMenuItem menuFileExit = new JMenuItem();

menuFile.setText("文件");

menuFile1.setText("编辑");

menuFile2.setText("查看");

menuFile3.setText("帮助");

menuFileExit.setText("退出");

menuFileExit.addActionListener

(

new ActionListener() {

public void actionPerformed(ActionEvent e) {

CounterFrame.this.windowClosed();

}

}

);

menuFile.add(menuFileExit);

menuBar.add(menuFile);

menuBar.add(menuFile1);

menuBar.add(menuFile2);

menuBar.add(menuFile3);

setTitle("计算器");

setJMenuBar(menuBar);

setSize(new Dimension(400, 280));

this.getContentPane().add(new Allpanel());

this.addWindowListener

(

new WindowAdapter() {

public void windowClosing(WindowEvent e) {

CounterFrame.this.windowClosed();

}

}

);

}

protected void windowClosed() {

System.exit(0);

}

}

class Tool {

public static Tool instance;

private JTextField field;

private Tool() {

this.field=new JTextField(30);

this.field.setHorizontalAlignment(JTextField.RIGHT);

}

public static Tool getinstance()

{

if(instance==null)

{

instance=new Tool();

}

return instance;

}

public JTextField getfield()

{

return (this.field);

}

}

class Allpanel extends JPanel {

public Allpanel() {

this.setLayout(new BorderLayout(0,7));

Northpanel np=new Northpanel();

Centerpanel cp=new Centerpanel();

this.add(np,BorderLayout.NORTH);

this.add(cp,BorderLayout.CENTER);

}

}

class Centercenter extends JPanel {

static Vector Vec=new Vector();

static Vector vc=new Vector();

static Vector vc1=new Vector();

static Vector vc2=new Vector();

static Vector vc3=new Vector();

static String begin="yes";

static double add;

static double jq;

static double cs;

static double cq;

static double dy;

static String jg;

static String what;

static double tool=0;

static String to="yes";

/**

* Method Centercenter

*

*

*/

public Centercenter() {

// TODO: Add your code here

final JTextField text=Tool.getinstance().getfield();

this.setLayout(new GridLayout(4,5,3,3));

String arg[] ={"7","8","9","/","sqrt","4","5","6","*","%","1","2","3","-","1/x","0","+/-",".","+","="};

for(int i=0;i20;i++)

{

final JButton b=new JButton(arg[i]);

//this.add(new JButton(arg[i]));

this.add(b);

if(i==0||i==1||i==2||i==5||i==6||i==7||i==10||i==11||i==12||i==15)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String mark=b.getText();

String ma=text.getText();

if(vc3.contains("v3"))

{

text.setText("0."+mark);

vc3.clear();

}

else if(vc.contains("a"))

{

if(vc2.contains("v2"))

{

text.setText("0."+mark);

vc.clear();

vc2.clear();

}

else

{

text.setText(mark);

vc.clear();

Vec.clear();

Vec.add(mark);

}

}

else

{

text.setText(ma.trim()+mark);

Vec.add(mark);

}

begin="no";

to="yes";

}

});

}

if(i==17)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String mar=b.getText();

String m=text.getText();

if("yes".equals(begin))

{

vc3.add("v3");

}

if(vc1.contains("v1"))

{

vc2.add("v2");

vc1.clear();

}

if(!Vec.contains(".")!vc.contains("a"))

{

text.setText(m.trim()+mar);

Vec.add(".");

}

}

});

}

if(i==18)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

add=Double.parseDouble(ma);

if(what==null)

{

tool=add;

what="add";

}

else

{

tool=tool+add;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="+";

}

});

}

if(i==13)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

jq=Double.parseDouble(ma);

if(what==null)

{

tool=jq;

what="jq";

}

else

{

tool=tool-jq;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="-";

}

});

}

if(i==3)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

cq=Double.parseDouble(ma);

if(what==null)

{

tool=cq;

what="cq";

}

else

{

tool=tool/cq;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="/";

}

});

}

if(i==4)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

cq=Double.parseDouble(ma);

text.setText(String.valueOf(Math.sqrt(cq)));

}

});

}

if(i==8)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

cs=Double.parseDouble(ma);

if(what==null)

{

tool=cs;

what="cs";

}

else

{

tool=tool*cs;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="*";

}

});

}

if(i==19)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

dy=Double.parseDouble(ma);

if(what=="add")

{

jg=String.valueOf((tool+dy));

}

if(what=="jq")

{

jg=String.valueOf((tool-dy));

}

if(what=="cs")

{

jg=String.valueOf((tool*dy));

}

if(what=="cq")

{

jg=String.valueOf((tool/dy));

}

if(what==null)

{

if(to=="+")

{

tool=add;

jg=String.valueOf(tool+dy);

}

else if(to=="-")

{

tool=jq;

jg=String.valueOf(dy-tool);

}

else if(to=="*")

{

tool=cs;

jg=String.valueOf(dy*tool);

}

else if(to=="/")

{

tool=cq;

jg=String.valueOf(dy/tool);

}

else

{

jg=String.valueOf(dy);

}

}

text.setText(jg);

Vec.clear();

Vec.add(".");

vc.add("a");

vc1.add("v1");

what=null;

tool=0;

}

});

}

}

}

}

class Centernorth extends JPanel {

public Centernorth() {

final JTextField text=Tool.getinstance().getfield();

JButton jb1=new JButton("Backspace");

JButton jb2=new JButton(" CE ");

JButton jb3=new JButton(" C ");

this.add(jb1);

this.add(jb2);

this.add(jb3);

jb1.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e)

{

String back=Tool.getinstance().getfield().getText();

text.setText(backmethod(back));

Centercenter.Vec.remove(Centercenter.Vec.size()-1);

}

});

jb3.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e)

{

text.setText("0.");

Centercenter.Vec.clear();

Centercenter.Vec.add(".");

Centercenter.vc.add("a");

Centercenter.begin="yes";

Centercenter.vc1.clear();

Centercenter.what=null;

Centercenter.tool=0;

}

});

}

public String backmethod(String str)

{

return str.substring(0,str.length()-1);

}

}

class Centerpanel extends JPanel {

public Centerpanel() {

this.setLayout(new BorderLayout(8,7));

Centernorth cn=new Centernorth();

Centercenter cc=new Centercenter();

Centerwest cw=new Centerwest();

this.add(cn,BorderLayout.NORTH);

this.add(cc,BorderLayout.CENTER);

this.add(cw,BorderLayout.WEST);

}

}

class Centerwest extends JPanel {

public Centerwest() {

this.setLayout(new GridLayout(4,1,3,3));

this.add(new JButton("MC"));

this.add(new JButton("MR"));

this.add(new JButton("MS"));

this.add(new JButton("M+"));

}

}

class Northpanel extends JPanel {

private JTextField tf;

public Northpanel() {

tf=Tool.getinstance().getfield();

this.add(tf);

}

}

---------------------------------------------------------------------------

=============《按你要求特意后改过的最简单功能的代码如下》========================

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.util.*;

public class Counter2 {

public static void main(String[] args) {

CounterFrame frame = new CounterFrame();

frame.show();

}

}

class CounterFrame extends JFrame {

public CounterFrame() {

setTitle("计算器");

setSize(new Dimension(400, 280));

this.getContentPane().add(new Allpanel());

this.addWindowListener

(

new WindowAdapter() {

public void windowClosing(WindowEvent e) {

CounterFrame.this.windowClosed();

}

}

);

}

protected void windowClosed() {

System.exit(0);

}

}

class Tool {

public static Tool instance;

private JTextField field;

private Tool() {

this.field=new JTextField(30);

this.field.setHorizontalAlignment(JTextField.RIGHT);

}

public static Tool getinstance()

{

if(instance==null)

{

instance=new Tool();

}

return instance;

}

public JTextField getfield()

{

return (this.field);

}

}

class Allpanel extends JPanel {

public Allpanel() {

this.setLayout(new BorderLayout(0,7));

Northpanel np=new Northpanel();

Centerpanel cp=new Centerpanel();

this.add(np,BorderLayout.NORTH);

this.add(cp,BorderLayout.CENTER);

}

}

class Centercenter extends JPanel {

static Vector Vec=new Vector();

static Vector vc=new Vector();

static Vector vc1=new Vector();

static Vector vc2=new Vector();

static Vector vc3=new Vector();

static String begin="yes";

static double add;

static double jq;

static double cs;

static double cq;

static double dy;

static String jg;

static String what;

static double tool=0;

static String to="yes";

/**

* Method Centercenter

*

*

*/

public Centercenter() {

// TODO: Add your code here

final JTextField text=Tool.getinstance().getfield();

this.setLayout(new GridLayout(4,5,3,3));

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

for(int i=0;i16;i++)

{

final JButton b=new JButton(arg[i]);

//this.add(new JButton(arg[i]));

this.add(b);

if(i==0||i==1||i==2||i==4||i==5||i==6||i==8||i==9||i==10||i==12)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String mark=b.getText();

String ma=text.getText();

if(vc3.contains("v3"))

{

text.setText("0."+mark);

vc3.clear();

}

else if(vc.contains("a"))

{

if(vc2.contains("v2"))

{

text.setText("0."+mark);

vc.clear();

vc2.clear();

}

else

{

text.setText(mark);

vc.clear();

Vec.clear();

Vec.add(mark);

}

}

else

{

text.setText(ma.trim()+mark);

Vec.add(mark);

}

begin="no";

to="yes";

}

});

}

if(i==14)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String mar=b.getText();

String m=text.getText();

if("yes".equals(begin))

{

vc3.add("v3");

}

if(vc1.contains("v1"))

{

vc2.add("v2");

vc1.clear();

}

if(!Vec.contains(".")!vc.contains("a"))

{

text.setText(m.trim()+mar);

Vec.add(".");

}

}

});

}

if(i==15)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

add=Double.parseDouble(ma);

if(what==null)

{

tool=add;

what="add";

}

else

{

tool=tool+add;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="+";

}

});

}

if(i==11)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

jq=Double.parseDouble(ma);

if(what==null)

{

tool=jq;

what="jq";

}

else

{

tool=tool-jq;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="-";

}

});

}

if(i==3)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

cq=Double.parseDouble(ma);

if(what==null)

{

tool=cq;

what="cq";

}

else

{

tool=tool/cq;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="/";

}

});

}

if(i==7)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

cs=Double.parseDouble(ma);

if(what==null)

{

tool=cs;

what="cs";

}

else

{

tool=tool*cs;

text.setText(String.valueOf((tool)));

}

vc.add("a");

vc1.add("v1");

to="*";

}

});

}

if(i==13)

{

b.addActionListener(new ActionListener()

{

public void actionPerformed(ActionEvent e)

{

String ma=text.getText();

dy=Double.parseDouble(ma);

if(what=="add")

{

jg=String.valueOf((tool+dy));

}

if(what=="jq")

{

jg=String.valueOf((tool-dy));

}

if(what=="cs")

{

jg=String.valueOf((tool*dy));

}

if(what=="cq")

{

jg=String.valueOf((tool/dy));

}

if(what==null)

{

if(to=="+")

{

tool=add;

jg=String.valueOf(tool+dy);

}

else if(to=="-")

{

tool=jq;

jg=String.valueOf(dy-tool);

}

else if(to=="*")

{

tool=cs;

jg=String.valueOf(dy*tool);

}

else if(to=="/")

{

tool=cq;

jg=String.valueOf(dy/tool);

}

else

{

jg=String.valueOf(dy);

}

}

text.setText(jg);

Vec.clear();

Vec.add(".");

vc.add("a");

vc1.add("v1");

what=null;

tool=0;

}

});

}

}

}

}

class Centernorth extends JPanel {

public Centernorth() {

final JTextField text=Tool.getinstance().getfield();

}

}

class Centerpanel extends JPanel {

public Centerpanel() {

this.setLayout(new BorderLayout(8,7));

Centernorth cn=new Centernorth();

Centercenter cc=new Centercenter();

Centerwest cw=new Centerwest();

this.add(cn,BorderLayout.NORTH);

this.add(cc,BorderLayout.CENTER);

this.add(cw,BorderLayout.WEST);

}

}

class Centerwest extends JPanel {

public Centerwest() {

}

}

class Northpanel extends JPanel {

private JTextField tf;

public Northpanel() {

tf=Tool.getinstance().getfield();

this.add(tf);

}

}

------------------------------------------------------------

才子_辉祝您愉快！

java课程的题目，问题在补充内，求高手。

Scanner input=new Scanner(System.in);

   System.out.println("请输入本月用电量:");

   int num=0;

   try {

   num=input.nextInt();

   } catch (Exception e) {

   System.out.println("请输入数字");

   }

   double count=0;

   if(num200){

   count=num*0.10;

   }else if(num=200  num=500){

   count=num*0.30;

   }else{

   count=num*0.50;

   }

   System.out.println("你需交电费:"+count);

java计算器的源代码

import java.awt.*;

import java.awt.event.*;

import java.lang.*;

import javax.swing.*;

public class Counter extends Frame

{

//声明三个面板的布局

GridLayout gl1,gl2,gl3;

Panel p0,p1,p2,p3;

JTextField tf1;

TextField tf2;

Button b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17,b18,b19,b20,b21,b22,b23,b24,b25,b26;

StringBuffer str;//显示屏所显示的字符串

double x,y;//x和y都是运算数

int z;//Z表示单击了那一个运算符.0表示"+",1表示"-",2表示"*",3表示"/"

static double m;//记忆的数字

public Counter()

{

gl1=new GridLayout(1,4,10,0);//实例化三个面板的布局

gl2=new GridLayout(4,1,0,15);

gl3=new GridLayout(4,5,10,15);

tf1=new JTextField(27);//显示屏

tf1.setHorizontalAlignment(JTextField.RIGHT);

tf1.setEnabled(false);

tf1.setText("0");

tf2=new TextField(10);//显示记忆的索引值

tf2.setEditable(false);

//实例化所有按钮、设置其前景色并注册监听器

b0=new Button("Backspace");

b0.setForeground(Color.red);

b0.addActionListener(new Bt());

b1=new Button("CE");

b1.setForeground(Color.red);

b1.addActionListener(new Bt());

b2=new Button("C");

b2.setForeground(Color.red);

b2.addActionListener(new Bt());

b3=new Button("MC");

b3.setForeground(Color.red);

b3.addActionListener(new Bt());

b4=new Button("MR");

b4.setForeground(Color.red);

b4.addActionListener(new Bt());

b5=new Button("MS");

b5.setForeground(Color.red);

b5.addActionListener(new Bt());

b6=new Button("M+");

b6.setForeground(Color.red);

b6.addActionListener(new Bt());

b7=new Button("7");

b7.setForeground(Color.blue);

b7.addActionListener(new Bt());

b8=new Button("8");

b8.setForeground(Color.blue);

b8.addActionListener(new Bt());

b9=new Button("9");

b9.setForeground(Color.blue);

b9.addActionListener(new Bt());

b10=new Button("/");

b10.setForeground(Color.red);

b10.addActionListener(new Bt());

b11=new Button("sqrt");

b11.setForeground(Color.blue);

b11.addActionListener(new Bt());

b12=new Button("4");

b12.setForeground(Color.blue);

b12.addActionListener(new Bt());

b13=new Button("5");

b13.setForeground(Color.blue);

b13.addActionListener(new Bt());

b14=new Button("6");

b14.setForeground(Color.blue);

b14.addActionListener(new Bt());

b15=new Button("*");

b15.setForeground(Color.red);

b15.addActionListener(new Bt());

b16=new Button("%");

b16.setForeground(Color.blue);

b16.addActionListener(new Bt());

b17=new Button("1");

b17.setForeground(Color.blue);

b17.addActionListener(new Bt());

b18=new Button("2");

b18.setForeground(Color.blue);

b18.addActionListener(new Bt());

b19=new Button("3");

b19.setForeground(Color.blue);

b19.addActionListener(new Bt());

b20=new Button("-");

b20.setForeground(Color.red);

b20.addActionListener(new Bt());

b21=new Button("1/X");

b21.setForeground(Color.blue);

b21.addActionListener(new Bt());

b22=new Button("0");

b22.setForeground(Color.blue);

b22.addActionListener(new Bt());

b23=new Button("+/-");

b23.setForeground(Color.blue);

b23.addActionListener(new Bt());

b24=new Button(".");

b24.setForeground(Color.blue);

b24.addActionListener(new Bt());

b25=new Button("+");

b25.setForeground(Color.red);

b25.addActionListener(new Bt());

b26=new Button("=");

b26.setForeground(Color.red);

b26.addActionListener(new Bt());

//实例化四个面板

p0=new Panel();

p1=new Panel();

p2=new Panel();

p3=new Panel();

//创建一个空字符串缓冲区

str=new StringBuffer();

//添加面板p0中的组件和设置其在框架中的位置和大小

p0.add(tf1);

p0.setBounds(10,25,300,40);

//添加面板p1中的组件和设置其在框架中的位置和大小

p1.setLayout(gl1);

p1.add(tf2);

p1.add(b0);

p1.add(b1);

p1.add(b2);

p1.setBounds(10,65,300,25);

//添加面板p2中的组件并设置其的框架中的位置和大小

p2.setLayout(gl2);

p2.add(b3);

p2.add(b4);

p2.add(b5);

p2.add(b6);

p2.setBounds(10,110,40,150);

//添加面板p3中的组件并设置其在框架中的位置和大小

p3.setLayout(gl3);//设置p3的布局

p3.add(b7);

p3.add(b8);

p3.add(b9);

p3.add(b10);

p3.add(b11);

p3.add(b12);

p3.add(b13);

p3.add(b14);

p3.add(b15);

p3.add(b16);

p3.add(b17);

p3.add(b18);

p3.add(b19);

p3.add(b20);

p3.add(b21);

p3.add(b22);

p3.add(b23);

p3.add(b24);

p3.add(b25);

p3.add(b26);

p3.setBounds(60,110,250,150);

//设置框架中的布局为空布局并添加4个面板

setLayout(null);

add(p0);

add(p1);

add(p2);

add(p3);

setResizable(false);//禁止调整框架的大小

//匿名类关闭窗口

addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e1)

{

System.exit(0);

}

});

setBackground(Color.lightGray);

setBounds(100,100,320,280);

setVisible(true);

}

//构造监听器

class Bt implements ActionListener

{

public void actionPerformed(ActionEvent e2)

{

try{

if(e2.getSource()==b1)//选择"CE"清零

{

tf1.setText("0");//把显示屏清零

str.setLength(0);//清空字符串缓冲区以准备接收新的输入运算数

}

else if(e2.getSource()==b2)//选择"C"清零

{

tf1.setText("0");//把显示屏清零

str.setLength(0);

}

else if(e2.getSource()==b23)//单击"+/-"选择输入的运算数是正数还是负数

{

x=Double.parseDouble(tf1.getText().trim());

tf1.setText(""+(-x));

}

else if(e2.getSource()==b25)//单击加号按钮获得x的值和z的值并清空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);//清空缓冲区以便接收新的另一个运算数

y=0d;

z=0;

}

else if(e2.getSource()==b20)//单击减号按钮获得x的值和z的值并清空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);

y=0d;

z=1;

}

else if(e2.getSource()==b15)//单击乘号按钮获得x的值和z的值并清空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);

y=0d;

z=2;

}

else if(e2.getSource()==b10)//单击除号按钮获得x的值和z的值并空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);

y=0d;

z=3;

}

else if(e2.getSource()==b26)//单击等号按钮输出计算结果

{

str.setLength(0);

switch(z)

{

case 0 : tf1.setText(""+(x+y));break;

case 1 : tf1.setText(""+(x-y));break;

case 2 : tf1.setText(""+(x*y));break;

case 3 : tf1.setText(""+(x/y));break;

}

}

else if(e2.getSource()==b24)//单击"."按钮输入小数

{

if(tf1.getText().trim().indexOf(′.′)!=-1)//判断字符串中是否已经包含了小数点

{

}

else//如果没数点有小

{

if(tf1.getText().trim().equals("0"))//如果初时显示为0

{

str.setLength(0);

tf1.setText((str.append("0"+e2.getActionCommand())).toString());

}

else if(tf1.getText().trim().equals(""))//如果初时显示为空则不做任何操作

{

}

else

{

tf1.setText(str.append(e2.getActionCommand()).toString());

}

}

y=0d;

}

else if(e2.getSource()==b11)//求平方根

{

x=Double.parseDouble(tf1.getText().trim());

tf1.setText("数字格式异常");

if(x0)

tf1.setText("负数没有平方根");

else

tf1.setText(""+Math.sqrt(x));

str.setLength(0);

y=0d;

}

else if(e2.getSource()==b16)//单击了"%"按钮

{

x=Double.parseDouble(tf1.getText().trim());

tf1.setText(""+(0.01*x));

str.setLength(0);

y=0d;

}

else if(e2.getSource()==b21)//单击了"1/X"按钮

{

x=Double.parseDouble(tf1.getText().trim());

if(x==0)

{

tf1.setText("除数不能为零");

}

else

{

tf1.setText(""+(1/x));

}

str.setLength(0);

y=0d;

}

else if(e2.getSource()==b3)//MC为清除内存

{

m=0d;

tf2.setText("");

str.setLength(0);

}

else if(e2.getSource()==b4)//MR为重新调用存储的数据

{

if(tf2.getText().trim()!="")//有记忆数字

{

tf1.setText(""+m);

}

}

else if(e2.getSource()==b5)//MS为存储显示的数据

{

m=Double.parseDouble(tf1.getText().trim());

tf2.setText("M");

tf1.setText("0");

str.setLength(0);

}

else if(e2.getSource()==b6)//M+为将显示的数字与已经存储的数据相加要查看新的数字单击MR

{

m=m+Double.parseDouble(tf1.getText().trim());

}

else//选择的是其他的按钮

{

if(e2.getSource()==b22)//如果选择的是"0"这个数字键

{

if(tf1.getText().trim().equals("0"))//如果显示屏显示的为零不做操作

{

}

else

{

tf1.setText(str.append(e2.getActionCommand()).toString());

y=Double.parseDouble(tf1.getText().trim());

}

}

else if(e2.getSource()==b0)//选择的是“BackSpace”按钮

{

if(!tf1.getText().trim().equals("0"))//如果显示屏显示的不是零

{

if(str.length()!=1)

{

tf1.setText(str.delete(str.length()-1,str.length()).toString());//可能抛出字符串越界异常

}

else

{

tf1.setText("0");

str.setLength(0);

}

}

y=Double.parseDouble(tf1.getText().trim());

}

else//其他的数字键

{

tf1.setText(str.append(e2.getActionCommand()).toString());

y=Double.parseDouble(tf1.getText().trim());

}

}

}

catch(NumberFormatException e){

tf1.setText("数字格式异常");

}

catch(StringIndexOutOfBoundsException e){

tf1.setText("字符串索引越界");

}

}

}

public static void main(String args[])

{

new Counter();

}

}

你在JAVA的环境中运行一下。

这题目也是我的作业，我运行的了。

要用java编的计算器代码

给你一个比较简单的吧。以前写的。

共两个类。还只是完成＋、－、×、÷运算而已。

GUI只是用了AWT，很简单，相信一看就能懂了。

Calculator.java

public class Calculator{

private String result = "0";

private int op = 0,add = 1,sub = 2,mul = 3,div = 4;

private double stringToDouble(String x){

double y = Double.parseDouble(x);

return y;

}

private void operate(String x){

double x1 = stringToDouble(x);

double y = stringToDouble(result);

switch (op){

case 0:

result = x;

break;

case 1:

result = String.valueOf(y+x1);

break;

case 2:

result = String.valueOf(y-x1);

break;

case 3:

result = String.valueOf(y*x1);

break;

case 4:

if(x1!=0){

result = String.valueOf(y/x1);

}else{

result = "The divisor can't be zero!";

}

break;

}

}

public String opAdd(String x){

operate(x);

op = add;

return result;

}

public String opSubtract(String x){

operate(x);

op = sub;

return result;

}

public String opMultiply(String x){

operate(x);

op = mul;

return result;

}

public String opDivide(String x){

operate(x);

op = div;

return result;

}

public String opEquals(String x){

operate(x);

op = 0;

return result;

}

public void opClean(){

op = 0;

result = "0";

}

}

CalculatorGUI.java

import java.awt.*;

import java.awt.event.*;

import java.util.EventObject;

public class CalculatorGUI{

private Frame f;

private Panel p1,p2;

private Button b0,b1,b2,b3,b4,b5,b6,b7,b8,b9;

private Button bPoint,bAdd,bDec,bMul,bDiv,bCal;

private TextField tf;

private String s,op;

private Calculator cal = new Calculator();

private boolean ifOp;

public CalculatorGUI(){

f = new Frame("Calculator");

p1 = new Panel();

p2 = new Panel();

b0 = new Button("0");

b1 = new Button("1");

b2 = new Button("2");

b3 = new Button("3");

b4 = new Button("4");

b5 = new Button("5");

b6 = new Button("6");

b7 = new Button("7");

b8 = new Button("8");

b9 = new Button("9");

bPoint = new Button(".");

bAdd = new Button("+");

bDec = new Button("-");

bMul = new Button("*");

bDiv = new Button("/");

bCal = new Button("=");

tf = new TextField(25);

tf.setEditable(false);

}

public void launchFrame(){

f.setSize(220,160);

f.setResizable(false);

f.addWindowListener(new myWindowListener());

p1.setLayout(new FlowLayout(FlowLayout.CENTER));

p1.add(tf);

f.add(p1,BorderLayout.NORTH);

p2.setLayout(new GridLayout(4,4));

b0.addActionListener(new setLabelText_ActionListener());

b1.addActionListener(new setLabelText_ActionListener());

b2.addActionListener(new setLabelText_ActionListener());

b3.addActionListener(new setLabelText_ActionListener());

b4.addActionListener(new setLabelText_ActionListener());

b5.addActionListener(new setLabelText_ActionListener());

b6.addActionListener(new setLabelText_ActionListener());

b7.addActionListener(new setLabelText_ActionListener());

b8.addActionListener(new setLabelText_ActionListener());

b9.addActionListener(new setLabelText_ActionListener());

bPoint.addActionListener(new setLabelText_ActionListener());

bAdd.addActionListener(new setOperator_ActionListener());

bDec.addActionListener(new setOperator_ActionListener());

bMul.addActionListener(new setOperator_ActionListener());

bDiv.addActionListener(new setOperator_ActionListener());

bCal.addActionListener(new setOperator_ActionListener());

p2.add(b7);

p2.add(b8);

p2.add(b9);

p2.add(bAdd);

p2.add(b4);

p2.add(b5);

p2.add(b6);

p2.add(bDec);

p2.add(b1);

p2.add(b2);

p2.add(b3);

p2.add(bMul);

p2.add(b0);

p2.add(bPoint);

p2.add(bCal);

p2.add(bDiv);

f.add(p2,BorderLayout.SOUTH);

f.setVisible(true);

}

public void setTextFieldText_Temp(){

if (tf.getText().length()15 (tf.getText().indexOf(".")==-1 || !s.equals("."))){

tf.setText(tf.getText()+s);

}else{

tf.setText((tf.getText()+s).substring(0,15));

}

}

public void setTextFieldText(){

if(ifOp){

ifOp = false;

tf.setText("");

setTextFieldText_Temp();

}else{

setTextFieldText_Temp();

}

}

public static void main(String[] args){

CalculatorGUI calculator = new CalculatorGUI();

calculator.launchFrame();

}

class myWindowListener extends WindowAdapter{

public void windowClosing(WindowEvent e){

System.exit(0);

}

}

class setLabelText_ActionListener implements ActionListener{

public void actionPerformed(ActionEvent e){

Button tempB = (Button)e.getSource();

s = tempB.getLabel();

setTextFieldText();

}

}

class setOperator_ActionListener implements ActionListener{

public void actionPerformed(ActionEvent e){

Button tempB = (Button)e.getSource();

op = tempB.getLabel();

if(op.equals("+")){

tf.setText(cal.opAdd(tf.getText()));

ifOp = true;

}else if(op.equals("-")){

tf.setText(cal.opSubtract(tf.getText()));

ifOp = true;

}else if(op.equals("*")){

tf.setText(cal.opMultiply(tf.getText()));

ifOp = true;

}else if(op.equals("/")){

tf.setText(cal.opDivide(tf.getText()));

ifOp = true;

}else if(op.equals("=")){

tf.setText(cal.opEquals(tf.getText()));

ifOp = true;

}

}

}

}

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