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,一闭锋起讨论.

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参考代码悔销如下

//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,所以轿前晌使用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());

}

}

JAVA计算器代码

import java.awt.*;

import java.applet.*;

public class CalculatorDemo extends Applet

{

TextField answerText;

Button pointButton,equalButton,plusButton;

Button minusButton,clearButton,multiButton,divisionButton;

Button[] b=new Button[10];

String currentOp,preOp;

String foreText,backText;

boolean isFloat=false;

public void init()

{

Panel p1=new Panel();

Panel p2=new Panel();

Panel p3=new Panel();

currentOp=new String("");

preOp=new String("");

foreText=new String("");

backText=new String("");

answerText=new TextField(8);

setBackground(Color.lightGray);

setForeground(Color.blue);

for(int i=9;i=0;i--)

{

b[i]=new Button(Integer.toString(i));

p2.add(b[i]);

}

pointButton=new Button(".");

equalButton=new Button("=");

equalButton.setForeground(Color.red);

clearButton=new Button("清除");

clearButton.setForeground(Color.red);

divisionButton=new Button("/");

divisionButton.setForeground(Color.red);

multiButton=new Button("*");

multiButton.setForeground(Color.red);

minusButton=new Button("-");

minusButton.setForeground(Color.red);

plusButton=new Button("+");

plusButton.setForeground(Color.red);

setLayout(new FlowLayout());

p1.setLayout(new FlowLayout());

p2.setLayout(new GridLayout(4,3));

p3.setLayout(new GridLayout(4,1));

p1.add(answerText);

p1.add(clearButton);

p2.add(pointButton);

p2.add(equalButton);

p3.add(plusButton);

p3.add(minusButton);

p3.add(multiButton);

p3.add(divisionButton);

add(p1);

add(p2);

add(p3);

}

public boolean action(Event e,Object o)

{

String s=new String("");

for(int i=0;i10;i++)

{

if(e.target==b[i]||e.target==pointButton)

{

if(e.target !=pointButton)

{

s=(String)o;

doForeText(s);

}

if((e.target==pointButton)(!isFloat))

{

isFloat=true;

s=(String)o;

if(foreText.equals(""))

{

foreText +="0.";

}

else

{

doForeText(s);

}

}

}

}

if(e.target==clearButton)

{

doClear();

}

if((e.target==clearButton)||(e.target==divisionButton)

||(e.target==plusButton)||(e.target==minusButton))

{

if(foreText !="")

{

currentOp=((String)o);

doOperator();

}

else

{

preOp=((String)o);

}

}

if(e.target==equalButton)

{

doOperator();

}

return true;

}

public void doOperator()

{

double dFore,dBack;

Double d;

if(preOp.equals(""))

{

backText=foreText;

foreText="";

answerText.setText(backText);

}

else

{

dFore=(new Double(foreText)).doubleValue();

dBack=(new Double(backText)).doubleValue();

foreText="";

backText=answerText.getText();

if(preOp.equals("+"))

{

d=new Double((dBack+dFore));

answerText.setText(d.toString());

backText=d.toString();

}

if(preOp.equals("-"))

{

d=new Double((dBack-dFore));

answerText.setText(d.toString());

backText=d.toString();

}

if(preOp.equals("*"))

{

d=new Double((dBack*dFore));

answerText.setText(d.toString());

backText=d.toString();

}

if(preOp.equals("/"))

{

if(dFore==0)

{

answerText.setText("除数不能为0");

return;

}

d=new Double((dBack/dFore));

answerText.setText(d.toString());

backText=d.toString();

}

}

preOp=currentOp;

}

public void doForeText(String s)

{

foreText +=s;

answerText.setText(foreText);

}

public void doBackText(String s)

{

backText=foreText;

foreText="";

answerText.setText(foreText);

}

public void doClear()

{

currentOp="";

preOp="";

foreText="";

backText="";

isFloat=false;

answerText.setText("");

}

}

用java.EE编写计算器程序代码

java EE是java企业级开发平台的棚芹旦意思，实在是看不出跟计算器这种小程序有什么关联。不知道楼主要找的是不是这个。

package ex1;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Dimension;

import java.awt.Font;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.text.DecimalFormat;

import javax.swing.BorderFactory;

import javax.swing.ButtonGroup;

import javax.swing.JButton;

import javax.swing.JCheckBoxMenuItem;

import javax.swing.JFrame;

import javax.swing.JMenu;

import javax.swing.JMenuBar;

import javax.swing.JMenuItem;

import javax.swing.JPanel;

import javax.swing.JRadioButtonMenuItem;

import javax.swing.JTextField;

public class Calcutor extends JFrame {

private JTextField tf;

private JPanel panel1, panel2, panel3, panel4;

private JMenuBar myBar;

private JMenu menu1, menu2, menu3;

private JMenuItem editItem1, editItem2, help1, help2, help3;

private JRadioButtonMenuItem seeItem1, seeItem2;//单选框

private JCheckBoxMenuItem seeItem3;//复选框

private ButtonGroup bgb;

private String back;

private boolean IfResult = true, flag = false;

private String oper = "=";

private double result = 0;

private Num numActionListener;

private DecimalFormat df;

public Calcutor(){

super("科学计算器");//设链扰置标题栏

df = new DecimalFormat("#.####");//保留四位小数

this.setLayout(new BorderLayout(10, 5));

panel1 = new JPanel(new GridLayout(1, 3, 10, 10));

panel2 = new JPanel(new GridLayout(5, 6, 5, 5));//5行6列

panel3 = new JPanel(new GridLayout(5, 1, 5, 5));

panel4 = new JPanel(new BorderLayout(5, 5));

/**

* 菜单栏

*/

myBar = new JMenuBar();

menu1 = new JMenu("编辑(E)");

menu2 = new JMenu("查看(V)");

menu3 = new JMenu("帮助(H)");

menu1.setFont(new Font("宋体", Font.PLAIN, 12));

menu2.setFont(new Font("宋体", Font.PLAIN, 12));

menu3.setFont(new Font("宋体", Font.PLAIN, 12));

/**

* 编辑栏

*/

editItem1 = new JMenuItem("首此复制(C) Ctrl+C");

editItem2 = new JMenuItem("粘贴(P) Ctrl+V");

editItem1.setFont(new Font("宋体",Font.PLAIN,12));

editItem2.setFont(new Font("宋体",Font.PLAIN,12));

/**

* 查看栏

*/

seeItem1 = new JRadioButtonMenuItem("科学型(T)");

seeItem2 = new JRadioButtonMenuItem("标准型(S)");

seeItem3 = new JCheckBoxMenuItem("数字分组(I)");

seeItem1.setFont(new Font("宋体",Font.PLAIN,12));

seeItem2.setFont(new Font("宋体",Font.PLAIN,12));

seeItem3.setFont(new Font("宋体",Font.PLAIN,12));

/**

* 帮助栏

*/

help1 = new JMenuItem("帮助主题(H)");

help2 = new JMenuItem("关于计算器(A)");

help1.setFont(new Font("宋体",Font.PLAIN,12));

help2.setFont(new Font("宋体",Font.PLAIN,12));

bgb = new ButtonGroup();//选项组

menu1.add(editItem1);

menu1.add(editItem2);

menu2.add(seeItem1);

menu2.add(seeItem2);

menu2.addSeparator();//添加一条分割线

menu2.add(seeItem3);

menu3.add(help1);

menu3.addSeparator();//添加一条分割线

menu3.add(help2);

myBar.add(menu1);

myBar.add(menu2);

myBar.add(menu3);

this.setJMenuBar(myBar);

numActionListener = new Num();//实现数字监听

/**

* 文本域，即为计算器的屏幕显示区域

*/

tf = new JTextField();

tf.setEditable(false);//文本区域不可编辑

tf.setBackground(Color.white);//文本区域的背景色

tf.setHorizontalAlignment(JTextField.RIGHT);//文字右对齐

tf.setText("0");

tf.setBorder(BorderFactory.createLoweredBevelBorder());

init();//对计算器进行初始化

}

/**

* 初始化操作

* 添加按钮

*/

private void init(){

addButton(panel1, "Backspace", new Clear(), Color.red);

addButton(panel1, "CE", new Clear(), Color.red);

addButton(panel1, "C", new Clear(), Color.red);

addButton(panel2, "1/x", new Signs(), Color.magenta);

addButton(panel2, "log", new Signs(), Color.magenta);

addButton(panel2, "7", numActionListener, Color.blue);

addButton(panel2, "8", numActionListener, Color.blue);

addButton(panel2, "9", numActionListener, Color.blue);

addButton(panel2, "÷", new Signs(), Color.red);

addButton(panel2, "n!", new Signs(), Color.magenta);

addButton(panel2, "sqrt", new Signs(), Color.magenta);

addButton(panel2, "4", numActionListener, Color.blue);

addButton(panel2, "5", numActionListener, Color.blue);

addButton(panel2, "6", numActionListener, Color.blue);

addButton(panel2, "×", new Signs(), Color.red);

addButton(panel2, "sin", new Signs(), Color.magenta);

addButton(panel2, "x^2", new Signs(), Color.magenta);

addButton(panel2, "1", numActionListener, Color.blue);

addButton(panel2, "2", numActionListener, Color.blue);

addButton(panel2, "3", numActionListener, Color.blue);

addButton(panel2, "-", new Signs(), Color.red);

addButton(panel2, "cos", new Signs(), Color.magenta);

addButton(panel2, "x^3", new Signs(), Color.magenta);

addButton(panel2, "0", numActionListener, Color.blue);

addButton(panel2, "-/+", new Clear(), Color.blue);

addButton(panel2, ".", new Dot(), Color.blue);

addButton(panel2, "+", new Signs(), Color.red);

addButton(panel2, "tan", new Signs(), Color.magenta);

addButton(panel2, "%", new Signs(), Color.magenta);

addButton(panel2, "π", numActionListener, Color.orange);

addButton(panel2, "e", numActionListener, Color.orange);

addButton(panel2, "′″", new Signs(), Color.orange);

addButton(panel2, "=", new Signs(), Color.red);

JButton btns = new JButton("计算器");

btns.setBorder(BorderFactory.createLoweredBevelBorder());

btns.setEnabled(false);//按钮不可操作

btns.setPreferredSize(new Dimension(20, 20));

panel3.add(btns);//加入按钮

addButton(panel3, "MC", null, Color.red);

addButton(panel3, "MR", null, Color.red);

addButton(panel3, "MS", null, Color.red);

addButton(panel3, "M+", null, Color.red);

panel4.add(panel1, BorderLayout.NORTH);

panel4.add(panel2, BorderLayout.CENTER);

this.add(tf, BorderLayout.NORTH);

this.add(panel3, BorderLayout.WEST);

this.add(panel4);

pack();

this.setResizable(false);//窗口不可改变大小

this.setLocation(300, 200);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

/**

* 统一设置按钮的的使用方式

* @param panel

* @param name

* @param action

* @param color

*/

private void addButton(JPanel panel, String name, ActionListener action, Color color){

JButton bt = new JButton(name);

panel.add(bt);//在面板上增加按钮

bt.setForeground(color);//设置前景（字体）颜色

bt.addActionListener(action);//增加监听事件

}

/**

* 计算器的基础操作（+ - × ÷）

* @param x

*/

private void getResult (double x){

if(oper == "+"){result += x;}

else if(oper == "-"){result -= x;}

else if(oper == "×"){result *= x;}

else if(oper == "÷"){result /= x;}

else if(oper == "="){result = x;}

tf.setText(df.format(result));

}

/**

* 运算符号的事件监听

*/

class Signs implements ActionListener{

public void actionPerformed(ActionEvent e) {

/*

* 用ActionEvent对象的getActionCommand()方法

* 取得与引发事件对象相关的字符串

*/

String str = e.getActionCommand();

/* sqrt求平方根 */

if(str.equals("sqrt")){

double i = Double.parseDouble(tf.getText());

if(i=0){

/*

* String.valueOf() 转换为字符串

* df.format() 按要求保留四位小数

* Math.sqrt() 求算数平方根

*/

tf.setText(String.valueOf(df.format(Math.sqrt(i))));

}

else{

tf.setText("负数不能开平方根");

}

}

/* log求常用对数 */

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

double i = Double.parseDouble(tf.getText());

if(i0){

tf.setText(String.valueOf(df.format(Math.log(i))));

}else{

tf.setText("负数不能求对数");

}

}

/* %求百分比 */

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

tf.setText(df.format(Double.parseDouble(tf.getText()) / 100));

}

/* 1/x求倒数 */

else if(str.equals("1/x")){

if(Double.parseDouble(tf.getText()) == 0){

tf.setText("除数不能为零");

}else{

tf.setText(df.format(1 / Double.parseDouble(tf.getText())));

}

}

/* sin求正弦函数 */

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

double i = Double.parseDouble(tf.getText());

tf.setText(String.valueOf(df.format(Math.sin(i))));

}

/* cos求余弦函数 */

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

double i = Double.parseDouble(tf.getText());

tf.setText(String.valueOf(df.format(Math.cos(i))));

}

/* tan求正切函数 */

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

double i = Double.parseDouble(tf.getText());

tf.setText(String.valueOf(df.format(Math.tan(i))));

}

/* n!求阶乘 */

else if(str.equals("n!")){

double i = Double.parseDouble(tf.getText());

if((i%2==0)||(i%2==1))//判断为整数放进行阶乘操作

{

int j = (int)i;//强制类型转换

int result=1;

for(int k=1;k=j;k++)

result *= k;

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

}

else

{

tf.setText("无法进行阶乘");

}

}

/* x^2求平方 */

else if(str.equals("x^2")){

double i = Double.parseDouble(tf.getText());

tf.setText(String.valueOf(df.format(i*i)));

}

/* x^3求立方 */

else if(str.equals("x^3")){

double i = Double.parseDouble(tf.getText());

tf.setText(String.valueOf(df.format(i*i*i)));

}

/* ′″角度转换 */

/**

* 将角度值转换成弧度值，方便三角函数的计算

*/

else if(str.equals("′″")){

double i = Double.parseDouble(tf.getText());

tf.setText(String.valueOf(i/180*Math.PI));

}

else{

if(flag){

IfResult = false;

}

if(IfResult){

oper = str;

}else{

getResult(Double.parseDouble(tf.getText()));

oper = str;

IfResult = true;

}

}

}

}

/**

* 清除按钮的事件监听

*/

class Clear implements ActionListener{

public void actionPerformed(ActionEvent e) {

/*

* 用ActionEvent对象的getActionCommand()方法

* 取得与引发事件对象相关的字符串

*/

String str = e.getActionCommand();

if(str == "C"){

tf.setText("0");

IfResult = true;

result = 0;

}else if(str == "-/+"){

double i = 0 - Double.parseDouble(tf.getText().trim());

tf.setText(df.format(i));

}else if(str == "Backspace"){

if(Double.parseDouble(tf.getText()) 0){

if(tf.getText().length() 1){

tf.setText(tf.getText().substring(0, tf.getText().length() - 1));

//使用退格删除最后一位字符

}else{

tf.setText("0");

IfResult = true;

}

}else{

if(tf.getText().length() 2){

tf.setText(tf.getText().substring(0, tf.getText().length() - 1));

}else{

tf.setText("0");

IfResult = true;

}

}

}else if(str == "CE"){

tf.setText("0");

IfResult = true;

}

}

}

/**

* 数字输入的事件监听

*/

class Num implements ActionListener{

public void actionPerformed(ActionEvent e) {

String str = e.getActionCommand();

if(IfResult){

tf.setText("");

IfResult = false;

}

if(str=="π")

{

tf.setText(String.valueOf(Math.PI));

}

else if(str=="e")

{

tf.setText(String.valueOf(Math.E));

}

else{

tf.setText(tf.getText().trim() + str);

if(tf.getText().equals("0")){

tf.setText("0");

IfResult = true;

flag = true;

}

}

}

}

/**

* 小数点的事件监听

*/

class Dot implements ActionListener{

public void actionPerformed(ActionEvent e) {

IfResult = false;

if(tf.getText().trim().indexOf(".") == -1){

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

}

}

}

/**

* main方法

*/

public static void main(String[] args) {

new Calcutor().setVisible(true);

}

}

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