用Java或C++写一个计算器，如图所示的？

采用java编写一个简单计算器，使用awt和swing

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代码如下：

import java.awt.Color;

import java.awt.Font;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

/*用java做一个计算器

* 实现整数和小数的加减乘除

* 具有删除和复位功能

*/

public class CaculatorDemo extends JFrame {

private static final long serialVersionUID = 1L;

private StringBuilder sBuilder = new StringBuilder();

private Double a;//中间变量用于存储输入的第一个数

private Double b;//中间变量，用于存储输入的第二个数

private Double double1;//用于接收计算结果

private Integer i;// i用于表示加减乘除

public CaculatorDemo() {

this.setTitle("计算器");

this.setSize(318, 457);

this.setLocationRelativeTo(null);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JPanel panel = new JPanel();

this.getContentPane().add(panel);

panel.setLayout(null);

// 定义一个label用于显示输入数据和计算结果，这里不用textfield，可以避免用户输入造成bug，简化程序开发

final JLabel label = new JLabel();

label.setBounds(0, 0, 300, 50);

label.setFont(new Font("dialog", 1, 30));

label.setOpaque(true);// 由于jlabel默认透明，直接设置背景色无效，需要先将不透明设置为true

label.setBackground(Color.white);

panel.add(label);

// 定义按钮组件

JButton button1 = new JButton("1");

JButton button2 = new JButton("2");

JButton button3 = new JButton("3");

JButton button4 = new JButton("4");

JButton button5 = new JButton("5");

JButton button6 = new JButton("6");

JButton button7 = new JButton("7");

JButton button8 = new JButton("8");

JButton button9 = new JButton("9");

JButton button0 = new JButton("0");

JButton buttonadd = new JButton("+");// 加

JButton buttonminus = new JButton("-");// 减

JButton buttontime = new JButton("×");// 乘

JButton buttondivid = new JButton("÷");// 除

JButton buttonequal = new JButton("=");// 等于

JButton buttondecimal = new JButton(".");// 小数点

JButton buttondelet = new JButton("←");// 删除

JButton buttonclear = new JButton("C");// 清除

// 定义按钮组件位置

button0.setBounds(0, 50, 100, 60);

button0.setFont(new Font("dialog", 1, 30));

panel.add(button0);

button1.setBounds(100, 50, 100, 60);

button1.setFont(new Font("dialog", 1, 30));

panel.add(button1);

button2.setBounds(200, 50, 100, 60);

button2.setFont(new Font("dialog", 1, 30));

panel.add(button2);

button3.setBounds(0, 110, 100, 60);

button3.setFont(new Font("dialog", 1, 30));

panel.add(button3);

button4.setBounds(100, 110, 100, 60);

button4.setFont(new Font("dialog", 1, 30));

panel.add(button4);

button5.setBounds(200, 110, 100, 60);

button5.setFont(new Font("dialog", 1, 30));

panel.add(button5);

button6.setBounds(0, 170, 100, 60);

button6.setFont(new Font("dialog", 1, 30));

panel.add(button6);

button7.setBounds(100, 170, 100, 60);

button7.setFont(new Font("dialog", 1, 30));

panel.add(button7);

button8.setBounds(200, 170, 100, 60);

button8.setFont(new Font("dialog", 1, 30));

panel.add(button8);

button9.setBounds(0, 230, 100, 60);

button9.setFont(new Font("dialog", 1, 30));

panel.add(button9);

buttonadd.setBounds(100, 230, 100, 60);

buttonadd.setFont(new Font("dialog", 1, 30));

panel.add(buttonadd);//加

buttonminus.setBounds(200, 230, 100, 60);

buttonminus.setFont(new Font("dialog", 1, 30));

panel.add(buttonminus);//减

buttontime.setBounds(0, 290, 100, 60);

buttontime.setFont(new Font("dialog", 1, 30));

panel.add(buttontime);//乘

buttondivid.setBounds(100, 290, 100, 60);

buttondivid.setFont(new Font("dialog", 1, 30));

panel.add(buttondivid);//除

buttonequal.setBounds(200, 290, 100, 60);

buttonequal.setFont(new Font("dialog", 1, 30));

panel.add(buttonequal);//等于

buttondecimal.setBounds(0, 350, 100, 60);

buttondecimal.setFont(new Font("dialog", 1, 30));

panel.add(buttondecimal);//小数点

buttonclear.setBounds(100, 350, 100, 60);

buttonclear.setFont(new Font("dialog", 1, 30));

panel.add(buttonclear);//复位

buttondelet.setBounds(200, 350, 100, 60);

buttondelet.setFont(new Font("dialog", 1, 30));

panel.add(buttondelet);//删除

// 给各个按钮设置动作监听器

// 输入数值操作0~9

button0.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("0");

label.setText(sBuilder.toString());

}

});

button1.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("1");

label.setText(sBuilder.toString());

}

});

button2.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

sBuilder.append("2");

label.setText(sBuilder.toString());

}

});

button3.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("3");

label.setText(sBuilder.toString());

}

});

button4.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("4");

label.setText(sBuilder.toString());

}

});

button5.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("5");

label.setText(sBuilder.toString());

}

});

button6.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("6");

label.setText(sBuilder.toString());

}

});

button7.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("7");

label.setText(sBuilder.toString());

}

});

button8.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("8");

label.setText(sBuilder.toString());

}

});

button9.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append("9");

label.setText(sBuilder.toString());

}

});

// 输入运算符操作，需要先判断a是否为0.0

buttonadd.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

a = Double.parseDouble(sBuilder.toString());

sBuilder = new StringBuilder();

label.setText("+");

i = 0;

}

});

buttonminus.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

a = Double.parseDouble(sBuilder.toString());

sBuilder = new StringBuilder();

label.setText("-");

i = 1;

}

});

buttontime.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

a = Double.parseDouble(sBuilder.toString());

sBuilder = new StringBuilder();

label.setText("×");

i = 2;

}

});

buttondivid.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

a = Double.parseDouble(sBuilder.toString());

sBuilder = new StringBuilder();

label.setText("÷");

i = 3;

}

});

buttonequal.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

// 该判断中间变量是否为空

if (!"".equals(sBuilder.toString()) (!(a == 0.0))) {

b = Double.parseDouble(sBuilder.toString());

if (i == 0) {

double1 = a + b;

label.setText(double1.toString());

sBuilder = new StringBuilder();

sBuilder.append(double1);

} else if (i == 1) {

double1 = a - b;

label.setText(double1.toString());

sBuilder = new StringBuilder();

sBuilder.append(double1);

} else if (i == 2) {

double1 = a * b;

label.setText(double1.toString());

sBuilder = new StringBuilder();

sBuilder.append(double1);

} else if (i == 3) {

double1 = a / b;

label.setText(double1.toString());

sBuilder = new StringBuilder();

sBuilder.append(double1);

} else {

label.setText(sBuilder.toString());

}

}

}

});

buttondecimal.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder.append(".");

label.setText(sBuilder.toString());

}

});

buttonclear.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

sBuilder = new StringBuilder();

label.setText("");

}

});

buttondelet.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

if (!"".equals(sBuilder.toString())) {

sBuilder.deleteCharAt(sBuilder.length() - 1);

label.setText(sBuilder.toString());

}

}

});

this.setVisible(true);

}

public static void main(String[] args) {

new CaculatorDemo();

}

}

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版权声明：本文为CSDN博主「散人陈某」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。

原文链接：

求一计算器java代码，最好简单一点（图形界面）

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();

}

}

求计算器Java代码。。。

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

import javax.swing.event.*;

class JPanelEa1 extends JFrame implements MenuListener,ActionListener

{

JPanel mainp,p1,p2,p3,p4;

JTextField jt1;

JMenuItem mnuCopy;

JMenuItem mnuPaste;

JButton bM;

boolean isDouble = false;// 是否为实数

int opFlag = -1;

static double t1 = 0, t2 = 0, t3 = 0, result = 0;

static int opflag1 = -1, opflag2 = -1, flag = 0, resflag = 1;

int preOp, currentOp = 0;// 标准位

double op1 = 0, op2 = 0;// 操作数

double n3;

StringBuffer buf = new StringBuffer(20);

StringBuffer copyBoard = new StringBuffer(20);// 剪贴板

StringBuffer memory = new StringBuffer(20);// M系列

StringBuffer str = new StringBuffer();

public JPanelEa1()

{

p1=new JPanel();

p1.setLayout(new GridLayout(2,1,10,10));

JMenuBar mnuNotepad=new JMenuBar();

JMenu mnuEdit=new JMenu("编辑(E)");

mnuEdit.setMnemonic(KeyEvent.VK_E);

JMenu mnuCheck=new JMenu("查看(V)");

mnuCheck.setMnemonic(KeyEvent.VK_V);

JMenu mnuHelp=new JMenu("帮助(H)");

mnuCopy=new JMenuItem("复制(C)");

mnuPaste=new JMenuItem("粘贴(P)");

JMenuItem mnuVisit=new JMenuItem("查看帮助(V)");

JMenuItem mnuAbout=new JMenuItem("关于计算器(A)");

JSeparator sep=new JSeparator();

jt1=new JTextField("0.");

jt1.setEnabled(false);

jt1.setHorizontalAlignment(JTextField.RIGHT);

mnuEdit.addMenuListener(this);

mnuCheck.addMenuListener(this);

mnuHelp.addMenuListener(this);

mnuCopy.addActionListener(this);

mnuPaste.addActionListener(this);

mnuVisit.addActionListener(this);

mnuAbout.addActionListener(this);

mnuNotepad.add(mnuEdit);

mnuNotepad.add(mnuCheck);

mnuNotepad.add(mnuHelp);

mnuEdit.add(mnuCopy);

mnuEdit.add(mnuPaste);

mnuEdit.add(sep);

mnuHelp.add(mnuVisit);

mnuHelp.add(sep);

mnuHelp.add(mnuAbout);

p1.add(mnuNotepad);

p1.add(jt1);

p2=new JPanel();

p2.setLayout(new FlowLayout(FlowLayout.CENTER));

bM = new JButton(" ");

bM.setEnabled(false);

p2.add(bM);

Button b25=new Button("Backspace");

b25.addActionListener(this);

Button b26=new Button("CE");

b26.addActionListener(this);

Button b27=new Button("C");

b27.addActionListener(this);

p2.add(b25);

p2.add(b26);

p2.add(b27);

p3=new JPanel();

p3.setLayout(new GridLayout(4,6));

Button button1=new Button("MC");

button1.addActionListener(this);

Button button2=new Button("7");

button2.addActionListener(this);

Button button3=new Button("8");

button3.addActionListener(this);

Button button4=new Button("9");

button4.addActionListener(this);

Button button5=new Button("/");

button5.addActionListener(this);

Button button6=new Button("sqrt");

button6.addActionListener(this);

Button button7=new Button("MR");

button7.addActionListener(this);

Button button8=new Button("4");

button8.addActionListener(this);

Button button9=new Button("5");

button9.addActionListener(this);

Button button10=new Button("6");

button10.addActionListener(this);

Button button11=new Button("*");

button11.addActionListener(this);

Button button12=new Button("%");

button12.addActionListener(this);

Button button13=new Button("MS");

button13.addActionListener(this);

Button button14=new Button("1");

button14.addActionListener(this);

Button button15=new Button("2");

button15.addActionListener(this);

Button button16=new Button("3");

button16.addActionListener(this);

Button button17=new Button("-");

button17.addActionListener(this);

Button button18=new Button("1/x");

button18.addActionListener(this);

Button button19=new Button("M+");

button19.addActionListener(this);

Button button20=new Button("0");

button20.addActionListener(this);

Button button21=new Button("+/-");

button21.addActionListener(this);

Button button22=new Button(".");

button22.addActionListener(this);

Button button23=new Button("+");

button23.addActionListener(this);

Button button24=new Button("=");

button24.addActionListener(this);

p3.add(button1);p3.add(button2);

p3.add(button3);p3.add(button4);

p3.add(button5);p3.add(button6);

p3.add(button7);p3.add(button8);

p3.add(button9);p3.add(button10);

p3.add(button11);p3.add(button12);

p3.add(button13);p3.add(button14);

p3.add(button15);p3.add(button16);

p3.add(button17);p3.add(button18);

p3.add(button19);p3.add(button20);

p3.add(button21);p3.add(button22);

p3.add(button23);p3.add(button24);

setSize(250,150);

mainp=new JPanel();

mainp.setLayout(new GridLayout(3,1));

mainp.add(p1);

mainp.add(p2);

mainp.add(p3);

setContentPane(mainp);

setTitle("计算器");

setSize(300,300);

setVisible(true);

setDefaultCloseOperation(EXIT_ON_CLOSE);

}

public void actionPerformed(ActionEvent e)

{

String s= e.getActionCommand();

if (s.equals("复制(C)")) {

String temp = jt1.getText().trim();

copyBoard.replace(0, copyBoard.length(), temp);

mnuPaste.setEnabled(true);

} else if (s.equals("粘贴(p)")) {

jt1.setText(copyBoard.toString());

} else if (s.equals("CE")) {

// 如果是CE则清除文本框

jt1.setText("0.");

} else if (s.equals("Backspace")) {

if (!jt1.getText().trim().equals("0.")) {

// 如果文本框中有内容

if (str.length() != 1 str.length() != 0) {

jt1.setText(str.delete(str.length() - 1, str.length())

.toString());

} else {

jt1.setText("0.");

str.setLength(0);

}

}

op2 = Double.parseDouble(jt1.getText().trim());

} else if (s.equals("C")) {

// 如果是C删除当前计算

jt1.setText("0.");

op1 = op2 = 0;

str.replace(0, str.length(), " ");

preOp = currentOp = 0;

} else if (s.equals("MC")) {

// 如果是MC则清除缓冲区

String temp = "";

memory.replace(0, memory.length(), temp);

bM.setText(" ");

} else if (s.equals("MR")) {

// 如果按键为MR则恢复缓冲区的数到文本框

jt1.setText(memory.toString());

} else if (s.equals("MS")) {

// 如果按键为MS则将文本框的数存入缓冲区

String s1 = jt1.getText().trim();

memory.replace(0, memory.length(), s1);

bM.setText("M");

} else if (s.equals("M+")) {

// 如果按键为MS则将文本框值与缓冲区的数相加但不显示结果

String temp1 = jt1.getText().trim();

double dtemp = Double.parseDouble(temp1);

String temp2 = memory.toString();

dtemp += Double.parseDouble(temp2);

temp1 = String.valueOf(dtemp);

memory.replace(0, memory.length(), temp1);

} else if (s.equals("1/x")) {

// 如果按键为1/x则将文本框中的数据为它的倒数

String temp = jt1.getText().trim();

double dtemp = Double.parseDouble(temp);

jt1.setText("" + 1 / dtemp);

} else if (s.equals("sqrt")) {

// 如果按键为sqrt则将文本框中的内容求平方根

String temp = jt1.getText().trim();

double dtemp = Double.parseDouble(temp);

jt1.setText("" + Math.sqrt(dtemp));

} else if (s.equals("+")) {

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 1;

op2 = 0;

jt1.setText("" + op1);

} else {

currentOp = preOp;

preOp = 1;

switch (currentOp) {

case 1:

op1 += op2;

jt1.setText("" + op1);

break;

case 2:

op1 -= op2;

jt1.setText("" + op1);

break;

case 3:

op1 *= op2;

jt1.setText("" + op1);

break;

case 4:

op1 /= op2;

jt1.setText("" + op1);

break;

}

}

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

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 2;// op1=op2;op2=0;

jt1.setText("" + op1);

} else {

currentOp = preOp;

preOp = 2;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("*"))// *

{

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 3;// op1=op2;op2=1;

jt1.setText("" + op1);// op1=op2;

} else {

currentOp = preOp;

preOp = 3;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("/"))// /

{

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 4;// op2=1;

jt1.setText("" + op1);// op1=op2;

} else {

currentOp = preOp;

preOp = 4;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("="))// =

{

if (currentOp == 0) {

str.setLength(0);

jt1.setText("" + op2);

} else {

str.setLength(0);

currentOp = preOp;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

currentOp = 0;

op2 = 0;

}

} else if (s.equals(".")) {

isDouble = true;

if (jt1.getText().trim().indexOf('.') != -1)

;

else {

if (jt1.getText().trim().equals("0")) {

str.setLength(0);

jt1.setText((str.append("0" + s)).toString());

}

// else

// if(jt1.getText().trim().equals("")){}//如果初时显示为空则不做任何操作

else {

jt1.setText((str.append(s)).toString());

}

}

} else if (s.equals("0"))// 如果选择的是"0"这个数字键

{

if (jt1.getText().trim().equals("0.")) {

} else {

jt1.setText(str.append(s).toString());

op2 = Double.parseDouble(jt1.getText().trim());

}

} else {

jt1.setText(str.append(s).toString());

op2 = Double.parseDouble(jt1.getText().trim());

if (currentOp == 0)

op1 = op2;

}

}

public static void main(String args[])

{

JPanelEa1 g=new JPanelEa1();

}

@Override

public void menuSelected(MenuEvent e) {

// TODO Auto-generated method stub

}

@Override

public void menuDeselected(MenuEvent e) {

// TODO Auto-generated method stub

}

@Override

public void menuCanceled(MenuEvent e) {

// TODO Auto-generated method stub

}

}

怎么用Java写一个计算器。下面有图片

//很简单，用脚本引擎类

import java.util.Scanner;

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

import javax.script.ScriptException;

public class ScriptEngineDemo

{

public static void main(String args[])

{

ScriptEngine sEngine = new ScriptEngineManager().getEngineByName("js");

Scanner scanner = new Scanner(System.in);

String express = "1+2*3";

System.out.println("请输入算是，按回车结束：");

String script = scanner.nextLine();

try {

Number num1 = (Number) sEngine.eval(express);

System.out.println(num1);

Number num2 = (Number) sEngine.eval(script);

System.out.println(num2);

} catch (ScriptException e) {

e.printStackTrace();

}

scanner.close();

}

}

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