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

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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();

}

}

用JAVA编写一个简单的计算器，要求如下:

然后 通过输入 显示结果，比如说：

以下是上图计算器的代码:

package Computer;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Container;

import java.awt.Font;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.util.Stack;

import javax.swing.JApplet;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

public class Count extends JApplet implements ActionListener

{

/**

*

*/

private static final long serialVersionUID = 1L;

private JTextField textField = new JTextField("请输入");

String operator = "";//操作

String input = "";//输入的 式子

boolean flag =  true;

//  boolean flag1 = true;

//  boolean flag2 = true;

public void init()//覆写Applet里边的init方法

{

Container C = getContentPane();

JButton b[] = new JButton[16];

JPanel panel = new JPanel();

C.add(textField, BorderLayout.NORTH);

C.add(panel,BorderLayout.CENTER);

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

String name[]={"7","8","9","+","4","5","6","-","1","2","3","*","0","C","=","/"};//设置 按钮

for(int i=0;i16;i++)//添加按钮

{

b[i] = new JButton(name[i]);

b[i].setBackground(new Color(192,192,192));

b[i].setForeground(Color.BLUE);//数字键 设置为 蓝颜色

if(i%4==3)

b[i].setForeground(Color.RED);

b[i].setFont(new Font("宋体",Font.PLAIN,16));//设置字体格式

panel.add(b[i]);

b[i].addActionListener(this);

}

b[13].setForeground(Color.RED);//非数字键，即运算键设置为红颜色

b[13].setForeground(Color.RED);

}

public void actionPerformed(ActionEvent e)

{

int cnt = 0;

String actionCommand = e.getActionCommand();

if(actionCommand.equals("+")||actionCommand.equals("-")||actionCommand.equals("*") ||actionCommand.equals("/"))

input +=" "+actionCommand+" ";//设置输入，把输入的样式改成 需要的样子

else if(actionCommand.equals("C"))

input = "";

else if(actionCommand.equals("="))//当监听到等号时，则处理 input

{

input+= "="+compute(input);

textField.setText(input);

input="";

cnt = 1;

}

else

input += actionCommand;//数字为了避免多位数的输入 不需要加空格

if(cnt==0)

textField.setText(input);

}

private String compute(String input)//即1237 的 样例

{

String str[];

str = input.split(" ");

StackDouble s = new StackDouble();

double m = Double.parseDouble(str[0]);

s.push(m);

for(int i=1;istr.length;i++)

{

if(i%2==1)

{

if(str[i].compareTo("+")==0)

{

double help = Double.parseDouble(str[i+1]);

s.push(help);

}

if(str[i].compareTo("-")==0)

{

double help = Double.parseDouble(str[i+1]);

s.push(-help);

}

if(str[i].compareTo("*")==0)

{

double help = Double.parseDouble(str[i+1]);

double ans = s.peek();//取出栈顶元素

s.pop();//消栈

ans*=help;

s.push(ans);

}

if(str[i].compareTo("/")==0)

{

double help = Double.parseDouble(str[i+1]);

double ans = s.peek();

s.pop();

ans/=help;

s.push(ans);

}

}

}

double ans = 0d;

while(!s.isEmpty())

{

ans+=s.peek();

s.pop();

}

String result = String.valueOf(ans);

return result;

}

public static void main(String args[])

{

JFrame frame = new JFrame("Count");

Count applet = new Count();

frame.getContentPane().add(applet, BorderLayout.CENTER);

applet.init();//applet的init方法

applet.start();//线程开始

frame.setSize(350, 400);//设置窗口大小

frame.setVisible(true);//设置窗口可见

}

}

用java实现一个简单的计算器。

/*

* @(#)JCalculator.java 1.00 06/17/2015

*/

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

/**

* A simple calculator program.

* pI saw this program in a QQ group, and help a friend correct it./p

*

* @author Singyuen Yip

* @version 1.00 12/29/2009

* @see JFrame

* @see ActionListener

*/

public class JCalculator extends JFrame implements ActionListener {

/**

* Serial Version UID

*/

private static final long serialVersionUID = -169068472193786457L;

/**

* This class help close the Window.

* @author Singyuen Yip

*

*/

private class WindowCloser extends WindowAdapter {

public void windowClosing(WindowEvent we) {

System.exit(0);

}

}

int i;

// Strings for Digit Operator buttons.

private final String[] str = { "7", "8", "9", "/", "4", "5", "6", "*","1",

"2", "3", "-", ".", "0", "=", "+" };

// Build buttons.

JButton[] buttons = new JButton[str.length];

// For cancel or reset.

JButton reset = new JButton("CE");

// Build the text field to show the result.

JTextField display = new JTextField("0");

/**

* Constructor without parameters.

*/

public JCalculator() {

super("Calculator");

// Add a panel.

JPanel panel1 = new JPanel(new GridLayout(4, 4));

// panel1.setLayout(new GridLayout(4,4));

for (i = 0; i  str.length; i++) {

buttons[i] = new JButton(str[i]);

panel1.add(buttons[i]);

}

JPanel panel2 = new JPanel(new BorderLayout());

// panel2.setLayout(new BorderLayout());

panel2.add("Center", display);

panel2.add("East", reset);

// JPanel panel3 = new Panel();

getContentPane().setLayout(new BorderLayout());

getContentPane().add("North", panel2);

getContentPane().add("Center", panel1);

// Add action listener for each digit operator button.

for (i = 0; i  str.length; i++)

buttons[i].addActionListener(this);

// Add listener for "reset" button.

reset.addActionListener(this);

// Add listener for "display" button.

display.addActionListener(this);

// The "close" button "X".

addWindowListener(new WindowCloser());

// Initialize the window size.

setSize(800, 800);

// Show the window.

// show(); Using show() while JDK version is below 1.5.

setVisible(true);

// Fit the certain size.

pack();

}

public void actionPerformed(ActionEvent e) {

Object target = e.getSource();

String label = e.getActionCommand();

if (target == reset)

handleReset();

else if ("0123456789.".indexOf(label) 0)

handleNumber(label);

else

handleOperator(label);

}

// Is the first digit pressed?

boolean isFirstDigit = true;

/**

* Number handling.

* @param key the key of the button.

*/

public void handleNumber(String key) {

if (isFirstDigit)

display.setText(key);

else if ((key.equals(".")) (display.getText().indexOf(".") 0))

display.setText(display.getText() + ".");

else if (!key.equals("."))

display.setText(display.getText() + key);

isFirstDigit = false;

}

/**

* Reset the calculator.

*/

public void handleReset() {

display.setText("0");

isFirstDigit = true;

operator = "=";

}

double number = 0.0;

String operator = "=";

/**

* Handling the operation.

* @param key pressed operator's key.

*/

public void handleOperator(String key) {

if (operator.equals("+"))

number += Double.valueOf(display.getText());

else if (operator.equals("-"))

number -= Double.valueOf(display.getText());

else if (operator.equals("*"))

number *= Double.valueOf(display.getText());

else if (operator.equals("/"))

number /= Double.valueOf(display.getText());

else if (operator.equals("="))

number = Double.valueOf(display.getText());

display.setText(String.valueOf(number));

operator = key;

isFirstDigit = true;

}

public static void main(String[] args) {

new JCalculator();

}

}

运行界面：

编写java程序简单计算器

主要涉及的知识点: 类的写法, 以及方法的调用 .建议多做练习. 如果有看不懂的地方. 可以继续追问,一起讨论.

参考代码如下

//Number类

class Number {

private int n1;//私有的整型数据成员n1

private int n2;//私有的整型数据成员n2

// 通过构造函数给n1和n2赋值

public Number(int n1, int n2) {

this.n1 = n1;

this.n2 = n2;

}

// 加法

public int addition() {

return n1 + n2;

}

// 减法

public int subtration() {

return n1 - n2;

}

// 乘法

public int multiplication() {

return n1 * n2;

}

// 除法 (可能除不尽,所以使用double作为返回类型)

public double division() {

return n1 * 1.0 / n2; // 通过n1*1.0 把计算结果转换成double类型.

}

}

//Exam4 类

public class Exam4{

public static void main(String[] args) {

Number number=new Number(15, 6);//创建Number类的对象

//下面的是调用方法得到返回值进行输出显示

System.out.println("加法"+number.addition());

System.out.println("减法"+number.subtration());

System.out.println("乘法"+number.multiplication());

System.out.println("除法"+number.division());

}

}