java编写计算器的代码 用java编写计算器代码

计算器java代码

import java.awt.Color;

import java.awt.Font;

import java.awt.GridLayout;

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;

import javax.swing.JTextField;

import javax.swing.WindowConstants;

import javax.swing.border.LineBorder;

class Normal{

double i,j;

public Normal(double num1,double num2){

i=num1;

j=num2;

}

public double puls(){

return i+j;

}

public double subtract(){

return i-j;

}

public double multiply(){

return i*j;

}

public double divide(){

return i/j;

}

public double surpuls(){

return i%j;

}

}

class scientific extends Normal{

public scientific(int num1, int num2) {

super(num1, num2);

}

}

public class calc extends JFrame{

public static void main(String[] args) {

viewNormal VN= new viewNormal("normal");

}

}

class viewNormal extends JFrame implements ActionListener{

JPanel jp1 = new JPanel(new GridLayout(4,3,5,5));

JPanel jp2 = new JPanel(new GridLayout(5,1,5,5));

JLabel jl;

JButton[] jb;

JButton jbs,jbo,jba,jbb,jbc,jby;

StringBuffer sb = new StringBuffer();

Normal normal;

int dot=0;

double fnum=0;

double lnum=0;

double result;

String sign=null;

public viewNormal(String title){

setTitle(title);

setLayout(null);

setVisible(true);

setBounds(200,200,305,350);

setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);

jb= new JButton[12];

for(int i=0;i9;i++){

jb[i]=new JButton(""+(i+1));

jp1.add(jb[i]);

jb[i].addActionListener(this);

}

jb[9]=new JButton(".");

jb[10]=new JButton("0");

jb[11]=new JButton("=");

jb[9].addActionListener(this);

jb[10].addActionListener(this);

jb[11].addActionListener(this);

jp1.add(jb[9]);

jp1.add(jb[10]);

jp1.add(jb[11]);

jp1.setBounds(10, 100, 200, 200);

jbs= new JButton("+");jbo= new JButton("-");jba= new JButton("*");

jbb= new JButton("/");jby= new JButton("%");jbc= new JButton("C");

jbs.addActionListener(this);jbo.addActionListener(this);jba.addActionListener(this);

jbb.addActionListener(this);jby.addActionListener(this);jbc.addActionListener(this);

//jp2.add(jby);

jp2.add(jbs);jp2.add(jbo);jp2.add(jba);jp2.add(jbb);jp2.add(jbc);

jp2.setBounds(215, 100, 70, 200);

jl= new JLabel("0",JLabel.RIGHT);

jl.setFont(new Font("Batang",Font.BOLD, 20));

jl.setBorder(new LineBorder(Color.black,2));

jl.setBackground(Color.white);

jl.setBounds(10, 40, 275, 50);

jl.setOpaque(true);

add(jl);

add(jp1);

add(jp2);

}

//+

public void sum(){

lnum=Double.parseDouble(sb.toString());

normal=new Normal(fnum,lnum);

fnum=normal.puls();

result=fnum;

}

//-

private void sub() {

System.out.println(sb.toString());

lnum=Double.parseDouble(sb.toString());

normal=new Normal(fnum,lnum);

fnum=normal.subtract();

result=fnum;

}

//*

private void mul() {

lnum=Double.parseDouble(sb.toString());

normal=new Normal(fnum,lnum);

fnum=normal.multiply();

result=fnum;

}

// /

private void div() {

lnum=Double.parseDouble(sb.toString());

normal=new Normal(fnum,lnum);

fnum=normal.divide();

result=fnum;

}

//%

private void sur() {

lnum=Double.parseDouble(sb.toString());

normal=new Normal(fnum,lnum);

fnum=normal.surpuls();

result=fnum;

}

// =

private void same(){

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

sum();

}

if(sign.equals("-")){

sub();

}

if(sign.equals("*")){

mul();

}

if(sign.equals("/")){

div();

}

if(sign.equals("%")){

sur();

}

}

//result

public void Result(){

if(result%1!=0)

jl.setText(""+result);

else

{

int i=(int)result;

jl.setText(""+i);

}

}

@Override

public void actionPerformed(ActionEvent e) {

//System.out.println(sb.toString());

// 1~9

for(int i=0;i9;i++){

if(e.getSource()==jb[i]!sb.toString().equals("0")){

sb.append(jb[i].getText());

jl.setText(sb.toString());

}

else if(e.getSource()==jb[i]sb.toString().equals("0")){

int d=sb.length();

sb.delete(0, d);

sb.append(jb[i].getText());

jl.setText(sb.toString());

}

}

// 0

if(e.getSource()==jb[10]!sb.toString().equals("0")){

sb.append(jb[10].getText());

jl.setText(sb.toString());

}

// .

if(e.getSource()==jb[9]dot==0!sb.toString().equals("")){

dot++;

sb.append(jb[9].getText());

jl.setText(sb.toString());

}

// =

if(e.getSource()==jb[11]!sb.toString().equals("")){

same();

Result();

int d=sb.length();

sb.delete(0, d);

dot=0;

}

// +

if(e.getSource()==jbs!sb.toString().equals("")){

if(sign!="+"sign!=null)

same();

else

sum();

sign ="+";

Result();

int d=sb.length();

sb.delete(0, d);

dot=0;

}

//-

if(e.getSource()==jbo!sb.toString().equals("")){

if(fnum==0)

fnum=2*Double.parseDouble(sb.toString());

if(sign!="-"sign!=null)

same();

else

sub();

sign ="-";

Result();

int d=sb.length();

sb.delete(0, d);

dot=0;

}

//*

if(e.getSource()==jba!sb.toString().equals("")){

if(fnum==0)

fnum=1;

if(sign!="*"sign!=null)

same();

else

mul();

sign ="*";

Result();

int d=sb.length();

sb.delete(0, d);

dot=0;

}

// /

if(e.getSource()==jbb!sb.toString().equals("")){

if(fnum==0)

fnum=Math.pow(Double.parseDouble(sb.toString()),2);

if(sign!="/"sign!=null)

same();

else

div();

sign ="/";

Result();

int d=sb.length();

sb.delete(0, d);

dot=0;

}

//%

// if(e.getSource()==jby!sb.toString().equals("")){

// if(fnum==0){

// fnum=Double.parseDouble(sb.toString());

// result=fnum;

// }

// else {

// if(sign!="%"sign!=null)

// same();

// else{

// lnum=Double.parseDouble(sb.toString());

// normal=new Normal(fnum,lnum);

// fnum=normal.surpuls();

// result=fnum;

// }

// }

// sign ="%";

// Result();

// int d=sb.length();

// sb.delete(0, d);

// dot=0;

// }

//clear

if(e.getSource()==jbc){

int d=sb.length();

sb.delete(0, d);

jl.setText("0");

dot=0;

fnum=0;

lnum=0;

sign=null;

}

}

}

class viewScientific extends viewNormal{

public viewScientific(String title){

super(title);

setBounds(200,200,800,500);

}

}

//等号以后输入符号用不了， String转 double 本来就有错误，你可以用我的扩展成科学型的。

求编写一个计算器的java代码

package com;

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

import java.text.DecimalFormat;

public class calculator implements ActionListener { //导入动作监听接口

//设计面板中的单位

JFrame frame;

JTextField textAnswer;

JPanel panel, panel1, panel2, panel3;

JMenuBar mainMenu;

JTextField textMemory;

JLabel labelMemSpace; //labelMemSpace单纯做摆设，控制面板的形状

JButton buttonBk, buttonCe, buttonC;

JButton button[];

JButton buttonMC, buttonMR, buttonMS, buttonMAdd;

JButton buttonDot, buttonAddAndSub, buttonAdd, buttonSub, buttonMul,

buttonDiv, buttonMod;

JButton buttonSqrt, buttonDao, buttonEqual;

JMenu editMenu, viewMenu, helpMenu;

JMenuItem copyItem, pasteItem, tItem, sItem, numberGroup, topHelp, aboutCal;

DecimalFormat df; //设置数据输出精度

boolean clickable; //控制当前能否按键

double memoryd; //使用内存中存储的数字

int memoryi;

double vard, answerd; //用来保存double型数据的中间值(vard)和最后结果(answerd)

short key = -1, prekey = -1; //key用来保存当前进行何种运算,prekey用来保存前次进行何种运算

String copy; //做复制用

JTextArea help; //帮助

JScrollPane scrollHelp;

//构造函数

@SuppressWarnings({ "static-access", "deprecation" })

public calculator() {

clickable = true;

answerd = 0;

frame = new JFrame("计算器");

df = new DecimalFormat("0.##############"); //设置数据输出精度(对于double型值)

textAnswer = new JTextField(15);

textAnswer.setText("");

textAnswer.setEditable(false);

textAnswer.setBackground(new Color(255, 255, 255));

panel = new JPanel();

frame.getContentPane().add(panel);

panel1 = new JPanel();

panel2 = new JPanel();

panel.setLayout(new BorderLayout());

//设计整个面板

JAVA 编写计算器 要代码最简单的

学java的时候自己编的，很简单，能够连续输入计算式后进行计算

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.FlowLayout;

import java.awt.Font;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.text.NumberFormat;

import java.util.ArrayList;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

/**简易计算器，能够进行简单的计算

*

* @see 2008.12.9

*/

public class CalculatorA

implements ActionListener{

private JFrame frame;

private JTextField field;

private JButton[] allButtons;

private JButton clearButton;

// private JButton backButton;

String result="";//保存结果

StringBuilder sb = new StringBuilder();//保存要进行的计算式

int x = 0; //用来判断上一次的事件类型

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

ArrayListString arrayList = new ArrayListString();//保存计算式，通过方法进行运算

public CalculatorA(){

frame = new JFrame("我的计算器v1.1");

frame.setLocation(300,300);

field = new JTextField(25);

allButtons = new JButton[16];

for(int i=0;iallButtons.length;i++){

allButtons[i]= new JButton(str.substring(i,i+1));

}

clearButton = new JButton("CLEAR");

// backButton = new JButton("——");

init();

setFondAndColor();

addEventHander();

}

public void init(){

frame.setLayout(new BorderLayout());

JPanel northPanel = new JPanel();

JPanel centerPanel = new JPanel();

JPanel southPanel = new JPanel();

northPanel.setLayout(new FlowLayout());

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

southPanel.setLayout(new FlowLayout());

northPanel.add(field);

for(int i=0;iallButtons.length;i++){

centerPanel.add(allButtons[i]);

}

southPanel.add(clearButton);

//southPanel.add(backButton);

frame.add(northPanel,BorderLayout.NORTH);

frame.add(centerPanel,BorderLayout.CENTER);

frame.add(southPanel,BorderLayout.SOUTH);

}

//设置输入字体

public void setFondAndColor(){

field.setFont(new Font("宋体",Font.BOLD,24));

field.setBackground(new Color(100,200,200));

field.setForeground(Color.RED);

//设置字体从右起始

field.setHorizontalAlignment(JTextField.RIGHT);

}

public void showMi(){

frame.pack();

frame.setResizable(false);

frame.setVisible(true);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

public void addEventHander(){

for(int i=0;iallButtons.length;i++){

allButtons[i].addActionListener(this);

}

clearButton.addActionListener(this);

// backButton.addActionListener(this);

}

@Override

public void actionPerformed(ActionEvent e) {

String str = e.getActionCommand();//取得当前事件返回的值

if("0123456789.".indexOf(str)!=-1){

if(x == 0){ //当x为0时表示还没有进行输入

result=str;

sb.append(str);

field.setText(str);

x = 1;

}

else if(x == 1){

result = result +str;

sb.append(str);

field.setText(result);

x = 1;

}

else if(x == 2){

sb.delete(0,sb.length());

result = result+str;

sb.append(str);

field.setText(result);

x = 1;

}

else if(x == 3){

result = str;

sb.delete(0,sb.length());

arrayList.clear();

field.setText(str);

sb.append(str);

field.setText(str);

x = 1;

}

else if(x == 4){

result ="";

sb.delete(0,sb.length());

arrayList.clear();

result = str;

sb.append(str);

field.setText(str);

x = 1;

}

else{

result = result +str;

sb.append(str);

field.setText(result);

x = 1;

}

}

else if("+*-/".indexOf(str)!=-1){

if(x == 0){

field.setText("");

x = 2;

}

else if(x == 1){

result = result + str;

arrayList.add(sb.toString());

arrayList.add(str);

sb.append(str);

field.setText(result);

x = 2;

}

else if(x == 2){

x = 2;

}

else if(x == 3){

field.setText(result+str);

arrayList.add(result);

arrayList.add(str);

result = result+str;

x = 2;

}

else if(x == 4){

result ="";

sb.delete(0,sb.length());

arrayList.clear();

x = 2;

}

else{

field.setText(result+str);

arrayList.add(result);

arrayList.add(str);

result = result+str;

x = 2;

}

}

else if("=".equals(str)){

if(x == 0){

field.setText("0");

arrayList.clear();

result = "0";

x = 3;

}

else if(x == 1){

try{

arrayList.add(sb.toString());

arrayList = getResult(arrayList);

result = arrayList.get(0);

field.setText(result);

arrayList.clear();

x = 3;

}catch(Exception e1){

field.setText("数据格式异常");

x = 0;

}

}

else if(x == 2){

field.setText("数据格式错误.....");

arrayList.clear();

x = 0;

}

else if(x == 3){

field.setText(result);

x = 3;

}

else if(x == 4){

result ="";

sb.delete(0,sb.length());

arrayList.clear();

x = 3;

}

else {

try{

arrayList.add(sb.toString());

arrayList = getResult(arrayList);

result = arrayList.get(0);

field.setText(result);

arrayList.clear();

x = 3;

}catch(Exception e1){

field.setText("数据格式异常");

x = 0;

}

}

}

else if("CLEAR".equals(str)){

arrayList.clear();

field.setText("0");

arrayList.add("0");

x = 4;

}

else{

if(result.length()1){

result = result.substring(0,result.length()-1);

if(sb.length()0){

sb.delete(sb.length()-1,sb.length());

}

else {

sb.delete(0,1);

}

field.setText(result);

x = 5;

}

else{

result = "";

sb.delete(0,sb.length());

arrayList.clear();

field.setText("0");

x = 0;

}

}

}

public static ArrayListString getResult(ArrayListString list){

String res = null;

String[] s = {"/","*","-","+"};

int i=0;

if(list.size()1){

for(;is.length;){

if(s[i].equals("/")){

for(int j=0;jlist.size();j++){

if(list.get(j).equals(s[i])){

res = Double.toString(Double.parseDouble(list.get(j-1))/Double.parseDouble(list.get(j+1)));

//本地的数据格式

NumberFormat nf = NumberFormat.getInstance();

res = nf.format(Double.parseDouble(res));

res = getChange(res);

list.set(j-1,res);

list.remove(j);

list.remove(j);

getResult(list);

}

}

i++;

}

else if(s[i].equals("*")){

for(int j=0;jlist.size();j++){

if(list.get(j).equals(s[i])){

res = Double.toString(Double.parseDouble(list.get(j-1))*Double.parseDouble(list.get(j+1)));

NumberFormat nf = NumberFormat.getInstance();

res = nf.format(Double.parseDouble(res));

res = getChange(res);

list.set(j-1,res);

list.remove(j);

list.remove(j);

getResult(list);

}

}

i++;

}

else if(s[i].equals("-")){

for(int j=0;jlist.size();j++){

if(list.get(j).equals(s[i])){

res = Double.toString(Double.parseDouble(list.get(j-1))-Double.parseDouble(list.get(j+1)));

NumberFormat nf = NumberFormat.getNumberInstance();

res = nf.format(Double.parseDouble(res));

res = getChange(res);

list.set(j-1,res);

list.remove(j);

list.remove(j);

getResult(list);

}

}

i++;

}

else {

for(int j=0;jlist.size();j++){

if(list.get(j).equals(s[i])){

res = Double.toString(Double.parseDouble(list.get(j-1))+Double.parseDouble(list.get(j+1)));

NumberFormat nf = NumberFormat.getInstance();

res = nf.format(Double.parseDouble(res));

res = getChange(res);

list.set(j-1,res);

list.remove(j);

list.remove(j);

getResult(list);

}

}

i++;

}

}

}

return list;

}

//对数字字符串进行排除不必要符号

public static String getChange(String res){

String s_temp = "";

char[] c = new char[res.length()];

for(int k=0;kc.length;k++){

c[k] = res.charAt(k);

}

for(int k=0;kc.length;k++){

if((c[k]= '0' c[k]= '9')|| c[k] == '.'){

s_temp += c[k];

}

}

return s_temp;

}

public static void main(String[] args){

new CalculatorA().showMi();

}

}

怎么用JAVA编程编写一个计算器？

打开IED：打开自己java编程的软件，采用的是eclipse软件。

建立java工程。

编写类。

编写类的详细步骤

1.类的基本结构：

由于这里用到了界面，所以要进行窗口界面的编程，按钮事件的处理，和计算处理界面；

package MyCaculator;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class MyCaculator extends JFrame {

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

private int op=0;

boolean ifOp;

private String output="0";

private Button[] jba=new Button[]{new Button("7"),new Button("8"),

new Button("9"),new Button("+"),

new Button("4"),new Button("5"),new Button("6"),new Button("-"),

new Button("1"),new Button("2"),new Button("3"),new Button("*"),

new Button("0"),new Button("."),new Button("="),new Button("/")};

private JPanel jpt=new JPanel();

private JPanel jpb=new JPanel();

private JTextField jtf=new JTextField("");

private MyCaculator(){

}

private void operate(String x){

}

public String add(String x){

return output;

}

public String subtract(String x){

return output;

}

public String multiply(String x){

return output;

}

public String divide(String x){

return output;

}

public String Equals(String x){

return output;

}

public void opClean(){

}

class setOperate_Act implements ActionListener{

public void actionPerformed(ActionEvent e) {

}

}

class setLabel_Act implements ActionListener{

public void actionPerformed(ActionEvent e) {

}

}

public static void main(String[] args) {

}

}

2.建立构造方法：

所谓构造方法就是，对自己的主类进行初始化，代码如下：

private MyCaculator(){

jpt.setLayout(new BorderLayout());

jpt.add(jtf);

this.add(jpt,BorderLayout.NORTH);

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

for(int i=0;ijba.length;i++){

jpb.add(jba[i]);

if(i==3||i==7||i==11||i==15||i==14)

jba[i].addActionListener(new setOperate_Act());

else

jba[i].addActionListener(new setLabel_Act());

}

this.add(jpb,BorderLayout.CENTER);

this.setSize(250, 200);

this.setResizable(false);

this.setVisible(true);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

3.建立数据计算方法

这里的数据计算方法有6个，一个是主方法其他几个是加减乘除的处理方法，代码如下：

private void operate(String x){

double x1=Double.valueOf(x);

double y=Double.valueOf(output);

switch(op){

case 0:output=x;break;

case 1:output=String.valueOf(y+x1);break;

case 2:output =String.valueOf(y-x1);break;

case 3:output =String.valueOf(y*x1);break;

case 4:

if(x1!=0) output=String.valueOf(y/x1);

else output="不能为0";

break;

}

}

public String add(String x){

operate(x);

op=add;

return output;

}

public String subtract(String x){

operate(x);

op=sub;

return output;

}

public String multiply(String x){

operate(x);

op=mul;

return output;

}

public String divide(String x){

operate(x);

op=div;

return output;

}

public String Equals(String x){

operate(x);

op=0;

return output;

}

public void opClean(){

op=0;

output ="0";

}

4.事件处理方法

这里的时间处理方法，没有建立一个整体的方法，二是在为了便于处理的方法，将按钮事件分成两个部分，并采用两个子类来实现，这两个类时内部类要写在主类内部的，代码如下：

class setOperate_Act implements ActionListener{

public void actionPerformed(ActionEvent e) {

if(e.getSource()==jba[3]){

jtf.setText(add(jtf.getText()));

ifOp=true;

}

else if(e.getSource()==jba[7]){

jtf.setText(subtract(jtf.getText()));

ifOp=true;

}

else if(e.getSource()==jba[11]){

jtf.setText(multiply(jtf.getText()));

ifOp=true;

}

else if(e.getSource()==jba[15]){

jtf.setText(divide(jtf.getText()));

ifOp=true;

}

else if(e.getSource()==jba[14]){

jtf.setText(Equals(jtf.getText()));

ifOp=true;

}

}

}

class setLabel_Act implements ActionListener{

public void actionPerformed(ActionEvent e) {

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

if(ifOp){

jtf.setText(tempb.getLabel());

ifOp=false;

}else {

jtf.setText(jtf.getText()+tempb.getLabel());

}

}

}

5.建立main方法：

要想实现我们的代码，我们需在main方法中，实例化我们的对象。

public static void main(String[] args) {

new MyCaculator();

}

java 计算器代码

import javax.swing.*;

import javax.swing.border.Border;

import java.awt.*;

import java.awt.event.ActionListener;

import java.awt.event.ActionEvent;

import java.math.BigDecimal;

import java.math.RoundingMode;

import java.util.HashMap;

/**

* 我的计算器。Cheshi 继承于 JFrame，是计算器的界面

c*/

public class Cheshi extends JFrame {

private Border border = BorderFactory.createEmptyBorder(5, 5, 5, 5);

private JTextField textbox = new JTextField("0");

private CalculatorCore core = new CalculatorCore();

private ActionListener listener = new ActionListener() {

public void actionPerformed(ActionEvent e) {

JButton b = (JButton) e.getSource();

String label = b.getText();

String result = core.process(label);

textbox.setText(result);

}

};

public Cheshi(String title) throws HeadlessException {

super(title); // 调用父类构造方法

setupFrame(); // 调整窗体属性

setupControls(); // 创建控件

}

private void setupControls() {

setupDisplayPanel(); // 创建文本面板

setupButtonsPanel(); // 创建按钮面板

}

// 创建按钮面板并添加按钮

private void setupButtonsPanel() {

JPanel panel = new JPanel();

panel.setBorder(border);

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

createButtons(panel, new String[]{

"7", "8", "9", "+", "C",

"4", "5", "6", "-", "CE",

"1", "2", "3", "*", "", // 空字符串表示这个位置没有按钮

"0", ".", "=", "/", ""

});

this.add(panel, BorderLayout.CENTER);

}

/**

* 在指定的面板上创建按钮

*

* @param panel 要创建按钮的面板

* @param labels 按钮文字

*/

private void createButtons(JPanel panel, String[] labels) {

for (String label : labels) {

// 如果 label 为空，则表示创建一个空面板。否则创建一个按钮。

if (label.equals("")) {

panel.add(new JPanel());

} else {

JButton b = new JButton(label);

b.addActionListener(listener); // 为按钮添加侦听器

panel.add(b);

}

}

}

// 设置显示面板，用一个文本框来作为计算器的显示部分。

private void setupDisplayPanel() {

JPanel panel = new JPanel();

panel.setLayout(new BorderLayout());

panel.setBorder(border);

setupTextbox();

panel.add(textbox, BorderLayout.CENTER);

this.add(panel, BorderLayout.NORTH);

}

// 调整文本框

private void setupTextbox() {

textbox.setHorizontalAlignment(JTextField.RIGHT); // 文本右对齐

textbox.setEditable(false); // 文本框只读

textbox.setBackground(Color.white); // 文本框背景色为白色

}

// 调整窗体

private void setupFrame() {

this.setDefaultCloseOperation(EXIT_ON_CLOSE); // 当窗体关闭时程序结束

this.setLocation(100, 50); // 设置窗体显示在桌面上的位置

this.setSize(300, 200); // 设置窗体大小

this.setResizable(false); // 窗体大小固定

}

// 程序入口

public static void main(String[] args) throws Exception {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

Cheshi frame = new Cheshi("我的计算器");

frame.setVisible(true); // 在桌面上显示窗体

}

}

/**

* 计算器核心逻辑。这个逻辑只能处理 1~2 个数的运算。

*/

class CalculatorCore {

private String displayText = "0"; // 要显示的文本

boolean reset = true;

private BigDecimal number1, number2;

private String operator;

private HashMapString, Operator operators = new HashMapString, Operator();

private HashMapString, Processor processors = new HashMapString, Processor();

CalculatorCore() {

setupOperators();

setupProcessors();

}

// 为每种命令添加处理方式

private void setupProcessors() {

processors.put("[0-9]", new Processor() {

public void calculate(String command) {

numberClicked(command);

}

});

processors.put("\\.", new Processor() {

public void calculate(String command) {

dotClicked();

}

});

processors.put("=", new Processor() {

public void calculate(String command) {

equalsClicked();

}

});

processors.put("[+\\-*/]", new Processor() {

public void calculate(String command) {

operatorClicked(command);

}

});

processors.put("C", new Processor() {

public void calculate(String command) {

clearClicked();

}

});

processors.put("CE", new Processor() {

public void calculate(String command) {

clearErrorClicked();

}

});

}

// 为每种 operator 添加处理方式

private void setupOperators() {

operators.put("+", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.add(number2);

}

});

operators.put("-", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.subtract(number2);

}

});

operators.put("*", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.multiply(number2);

}

});

operators.put("/", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.divide(number2, 30, RoundingMode.HALF_UP);

}

});

}

// 根据命令处理。这里的命令实际上就是按钮文本。

public String process(String command) {

for (String pattern : processors.keySet()) {

if (command.matches(pattern)) {

processors.get(pattern).calculate(command);

break;

}

}

return displayText;

}

// 当按下 CE 时

private void clearErrorClicked() {

if (operator == null) {

number1 = null;

} else {

number2 = null;

}

displayText = "0";

reset = true;

}

// 当按下 C 时，将计算器置为初始状态。

private void clearClicked() {

number1 = null;

number2 = null;

operator = null;

displayText = "0";

reset = true;

}

// 当按下 = 时

private void equalsClicked() {

calculateResult();

number1 = null;

number2 = null;

operator = null;

reset = true;

}

// 计算结果

private void calculateResult() {

number2 = new BigDecimal(displayText);

Operator oper = operators.get(operator);

if (oper != null) {

BigDecimal result = oper.process(number1, number2);

displayText = result.toString();

}

}

// 当按下 +-*/ 时（这里也可以扩展成其他中间操作符）

private void operatorClicked(String command) {

if (operator != null) {

calculateResult();

}

number1 = new BigDecimal(displayText);

operator = command;

reset = true;

}

// 当按下 . 时

private void dotClicked() {

if (displayText.indexOf(".") == -1) {

displayText += ".";

} else if (reset) {

displayText = "0.";

}

reset = false;

}

// 当按下 0-9 时

private void numberClicked(String command) {

if (reset) {

displayText = command;

} else {

displayText += command;

}

reset = false;

}

// 运算符处理接口

interface Operator {

BigDecimal process(BigDecimal number1, BigDecimal number2);

}

// 按钮处理接口

interface Processor {

void calculate(String command);

}

}

用JAVA编写一个计算器

import javax.swing.*;

import javax.swing.border.Border;

import java.awt.*;

import java.awt.event.ActionListener;

import java.awt.event.ActionEvent;

import java.math.BigDecimal;

import java.math.RoundingMode;

import java.util.HashMap;

/**

* 我的计算器。Cheshi 继承于 JFrame，是计算器的界面

c*/

public class Cheshi extends JFrame {

private Border border = BorderFactory.createEmptyBorder(5, 5, 5, 5);

private JTextField textbox = new JTextField("0");

private CalculatorCore core = new CalculatorCore();

private ActionListener listener = new ActionListener() {

public void actionPerformed(ActionEvent e) {

JButton b = (JButton) e.getSource();

String label = b.getText();

String result = core.process(label);

textbox.setText(result);

}

};

public Cheshi(String title) throws HeadlessException {

super(title); // 调用父类构造方法

setupFrame(); // 调整窗体属性

setupControls(); // 创建控件

}

private void setupControls() {

setupDisplayPanel(); // 创建文本面板

setupButtonsPanel(); // 创建按钮面板

}

// 创建按钮面板并添加按钮

private void setupButtonsPanel() {

JPanel panel = new JPanel();

panel.setBorder(border);

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

createButtons(panel, new String[]{

"7", "8", "9", "+", "C",

"4", "5", "6", "-", "CE",

"1", "2", "3", "*", "", // 空字符串表示这个位置没有按钮

"0", ".", "=", "/", ""

});

this.add(panel, BorderLayout.CENTER);

}

/**

* 在指定的面板上创建按钮

*

* @param panel 要创建按钮的面板

* @param labels 按钮文字

*/

private void createButtons(JPanel panel, String[] labels) {

for (String label : labels) {

// 如果 label 为空，则表示创建一个空面板。否则创建一个按钮。

if (label.equals("")) {

panel.add(new JPanel());

} else {

JButton b = new JButton(label);

b.addActionListener(listener); // 为按钮添加侦听器

panel.add(b);

}

}

}

// 设置显示面板，用一个文本框来作为计算器的显示部分。

private void setupDisplayPanel() {

JPanel panel = new JPanel();

panel.setLayout(new BorderLayout());

panel.setBorder(border);

setupTextbox();

panel.add(textbox, BorderLayout.CENTER);

this.add(panel, BorderLayout.NORTH);

}

// 调整文本框

private void setupTextbox() {

textbox.setHorizontalAlignment(JTextField.RIGHT); // 文本右对齐

textbox.setEditable(false); // 文本框只读

textbox.setBackground(Color.white); // 文本框背景色为白色

}

// 调整窗体

private void setupFrame() {

this.setDefaultCloseOperation(EXIT_ON_CLOSE); // 当窗体关闭时程序结束

this.setLocation(100, 50); // 设置窗体显示在桌面上的位置

this.setSize(300, 200); // 设置窗体大小

this.setResizable(false); // 窗体大小固定

}

// 程序入口

public static void main(String[] args) throws Exception {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

Cheshi frame = new Cheshi("我的计算器");

frame.setVisible(true); // 在桌面上显示窗体

}

}

/**

* 计算器核心逻辑。这个逻辑只能处理 1~2 个数的运算。

*/

class CalculatorCore {

private String displayText = "0"; // 要显示的文本

boolean reset = true;

private BigDecimal number1, number2;

private String operator;

private HashMapString, Operator operators = new HashMapString, Operator();

private HashMapString, Processor processors = new HashMapString, Processor();

CalculatorCore() {

setupOperators();

setupProcessors();

}

// 为每种命令添加处理方式

private void setupProcessors() {

processors.put("[0-9]", new Processor() {

public void calculate(String command) {

numberClicked(command);

}

});

processors.put("\\.", new Processor() {

public void calculate(String command) {

dotClicked();

}

});

processors.put("=", new Processor() {

public void calculate(String command) {

equalsClicked();

}

});

processors.put("[+\\-*/]", new Processor() {

public void calculate(String command) {

operatorClicked(command);

}

});

processors.put("C", new Processor() {

public void calculate(String command) {

clearClicked();

}

});

processors.put("CE", new Processor() {

public void calculate(String command) {

clearErrorClicked();

}

});

}

// 为每种 operator 添加处理方式

private void setupOperators() {

operators.put("+", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.add(number2);

}

});

operators.put("-", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.subtract(number2);

}

});

operators.put("*", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.multiply(number2);

}

});

operators.put("/", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.divide(number2, 30, RoundingMode.HALF_UP);

}

});

}

// 根据命令处理。这里的命令实际上就是按钮文本。

public String process(String command) {

for (String pattern : processors.keySet()) {

if (command.matches(pattern)) {

processors.get(pattern).calculate(command);

break;

}

}

return displayText;

}

// 当按下 CE 时

private void clearErrorClicked() {

if (operator == null) {

number1 = null;

} else {

number2 = null;

}

displayText = "0";

reset = true;

}

// 当按下 C 时，将计算器置为初始状态。

private void clearClicked() {

number1 = null;

number2 = null;

operator = null;

displayText = "0";

reset = true;

}

// 当按下 = 时

private void equalsClicked() {

calculateResult();

number1 = null;

number2 = null;

operator = null;

reset = true;

}

// 计算结果

private void calculateResult() {

number2 = new BigDecimal(displayText);

Operator oper = operators.get(operator);

if (oper != null) {

BigDecimal result = oper.process(number1, number2);

displayText = result.toString();

}

}

// 当按下 +-*/ 时（这里也可以扩展成其他中间操作符）

private void operatorClicked(String command) {

if (operator != null) {

calculateResult();

}

number1 = new BigDecimal(displayText);

operator = command;

reset = true;

}

// 当按下 . 时

private void dotClicked() {

if (displayText.indexOf(".") == -1) {

displayText += ".";

} else if (reset) {

displayText = "0.";

}

reset = false;

}

// 当按下 0-9 时

private void numberClicked(String command) {

if (reset) {

displayText = command;

} else {

displayText += command;

}

reset = false;

}

// 运算符处理接口

interface Operator {

BigDecimal process(BigDecimal number1, BigDecimal number2);

}

// 按钮处理接口

interface Processor {

void calculate(String command);

}

}

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