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java计算器,java计算器代码

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java编写计算器!

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class Calculator extends JFrame {

private Container container;

private GridBagLayout layout;

private GridBagConstraints constraints;

private JTextField displayField;//计算结果显示区

private String lastCommand;//保存+,-,*,/,=命令

private double result;//保存计算结果

private boolean start;//判断是否为数字的开始

public Calculator() {

super("计算器");

container=getContentPane();

layout=new GridBagLayout();

container.setLayout(layout);

constraints=new GridBagConstraints();

start=true;

result=0;

lastCommand = "=";

displayField=new JTextField(20);

displayField.setText("0.0");

displayField.setCaretColor(Color.red);

displayField.setHorizontalAlignment(JTextField.RIGHT);

constraints.gridx=0;

constraints.gridy=0;

constraints.gridwidth=4;

constraints.gridheight=1;

constraints.fill=GridBagConstraints.BOTH;

constraints.weightx=100;

constraints.weighty=100;

layout.setConstraints(displayField,constraints);

container.add(displayField);

ActionListener insert = new InsertAction();

ActionListener command = new CommandAction();

addButton("7",0,2,1,1,insert);

addButton("8",1,2,1,1,insert);

addButton("9",2,2,1,1,insert);

addButton("/",3,5,1,1,command);

addButton("4",0,3,1,1,insert);

addButton("5",1,3,1,1,insert);

addButton("6",2,3,1,1,insert);

addButton("*",3,4,1,1,command);

addButton("1",0,4,1,1,insert);

addButton("2",1,4,1,1,insert);

addButton("3",2,4,1,1,insert);

addButton("-",3,3,1,1,command);

addButton("0",1,5,1,1,insert);

addButton("=",2,5,1,1,command);

addButton(".",0,5,1,1,insert);

addButton("+",3,2,1,1,command);

setSize(180,200);

setVisible(true);

}

private void addButton(String label,int row,int column,int with,int height,ActionListener listener) {

JButton button=new JButton(label);

constraints.gridx=row;

constraints.gridy=column;

constraints.gridwidth=with;

constraints.gridheight=height;

constraints.fill=GridBagConstraints.BOTH;

button.addActionListener(listener);

layout.setConstraints(button,constraints);

container.add(button);

}

private class InsertAction implements ActionListener {

public void actionPerformed(ActionEvent event) {

String input=event.getActionCommand();

if (start) {

displayField.setText("");

start=false;

displayField.setText(displayField.getText()+input);

}

}

}

private class CommandAction implements ActionListener {

public void actionPerformed(ActionEvent evt) {

String command=evt.getActionCommand();

if(start) {

lastCommand=command;

}else {

calculate(Double.parseDouble(displayField.getText()));

lastCommand=command;

start=true;

}

}

}

public void calculate(double x) {

if (lastCommand.equals("+")) result+= x;

else if (lastCommand.equals("-")) result-=x;

else if (lastCommand.equals("*")) result*=x;

else if (lastCommand.equals("/")) result/=x;

else if (lastCommand.equals("=")) result=x;

displayField.setText(""+ result);

}

public static void main(String []args) {

Calculator calculator=new Calculator();

calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}

如何用Java编程迷你计算器

现在是一段核心程序,只有单位数的四则运算,需要实现多位数运算和小数点功能,最好还有正负号。万分感谢!

import java.awt.*;

import java.applet.*;

public class calc10 extends Applet {

char key,prevopr;

float ans,num;

char[] btext={'0','1','2','3','4','5',

'6','7','8','9','-','+','*','/'};

Button[] buttons = new Button[btext.length];

public void init() {

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

buttons[i] = new Button(""+btext[i]);

add(buttons[i]);

}

}

public float apply(float num1, char opr, float num2) {

switch (opr) {

case '+': return(ans+num);

case '-': return(ans-num);

case '*': return(ans*num);

case '/': return(ans/num);

default: return(num);

}

}

public boolean action(Event evt,Object arg){

key = ((String)arg).charAt(0);

if(key='0' key='9') {

num = (float)(key-'0');

showStatus(""+key);

} else {

ans = apply(ans,prevopr,num);

showStatus( "" + ans );

prevopr=key;

}

return true;

}

}

java计算器

import java.awt.BorderLayout;

import java.awt.Button;

import java.awt.Container;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

import javax.swing.JFrame;

import javax.swing.JOptionPane;

import javax.swing.JPanel;

import javax.swing.JTextField;

import javax.swing.WindowConstants;

public class Caculator extends JFrame implements ActionListener,KeyListener{

private JTextField tf=new JTextField();

private float x=0;

private float y=0;

private int code=0;

private boolean enable;

private boolean first;

private String str="";

public Caculator(){

Container ct=this.getContentPane();

this.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);

tf.setHorizontalAlignment(JTextField.RIGHT);

//tf.setText("0");

enable=true;

first=true;

ct.add(tf,BorderLayout.NORTH);

JPanel panel=new JPanel();

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

this.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e){

if(JOptionPane.YES_OPTION==JOptionPane.showConfirmDialog(Caculator.this,"确定要关闭程序吗?","提示",JOptionPane.OK_CANCEL_OPTION,JOptionPane.QUESTION_MESSAGE)){

e.getWindow().setVisible(false);

e.getWindow().dispose();

System.exit(0);

}

}

});

Button btn=null;

btn=new Button("1");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("2");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("3");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("+");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("4");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("5");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("6");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("-");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("7");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("8");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("9");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("*");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("0");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button(".");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("/");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("=");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

this.add(panel,BorderLayout.CENTER);

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

Caculator mainframe=new Caculator();

mainframe.setTitle("testing Caculator");

mainframe.setSize(400,400);

mainframe.setVisible(true);

}

public void actionPerformed(ActionEvent e) {

// TODO Auto-generated method stub

if(e.getActionCommand()=="+"){

x= Float.parseFloat(tf.getText());

code=0;

this.tf.setText("");

}

if(e.getActionCommand()=="-"){

x= Float.parseFloat(tf.getText());

code=1;

this.tf.setText("");

}

if(e.getActionCommand()=="*"){

x= Float.parseFloat(tf.getText());

code=2;

this.tf.setText("");

}

if(e.getActionCommand()=="/"){

x= Float.parseFloat(tf.getText());

code=3;

this.tf.setText("");

}

if(e.getActionCommand()!="+"e.getActionCommand()!="-"e.getActionCommand()!="*"e.getActionCommand()!="/"e.getActionCommand()!="="){

if(enable){

if(first){

System.out.println("haha");

tf.setText(e.getActionCommand());

first=false;

}

else {

tf.setText(tf.getText()+e.getActionCommand());

}

}

else {

tf.setText(e.getActionCommand());

enable=true;

}

}

if(e.getActionCommand()=="="){

switch(code){

case 0:

y=x+Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 1:

y=x-Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 2:

y=x*Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 3:

y=x/Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

}

}

}

public void keyPressed(KeyEvent e) {

// TODO Auto-generated method stub

if(e.getKeyChar()=='+'){

x= Float.parseFloat(tf.getText());

code=0;

this.tf.setText("");

}

if(e.getKeyChar()=='-'){

x= Float.parseFloat(tf.getText());

code=1;

this.tf.setText("");

}

if(e.getKeyChar()=='*'){

x= Float.parseFloat(tf.getText());

code=2;

this.tf.setText("");

}

if(e.getKeyChar()=='/'){

x= Float.parseFloat(tf.getText());

code=3;

this.tf.setText("");

}

if(e.getKeyChar()=='1'||e.getKeyChar()=='2'||e.getKeyChar()=='3'||e.getKeyChar()=='0'

||e.getKeyChar()=='4'||e.getKeyChar()=='5'||e.getKeyChar()=='6'||e.getKeyChar()=='.'

||e.getKeyChar()=='7'||e.getKeyChar()=='8'||e.getKeyChar()=='9'){

System.out.println("hai");

if(enable){

if(first){

System.out.println("hehe");

str=Character.toString(e.getKeyChar());

tf.setText(str);

first=false;

}

else {

str=Character.toString(e.getKeyChar());

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

}

}

else {

str=Character.toString(e.getKeyChar());

tf.setText(str);

enable=true;

}

}

if(e.getKeyCode()==KeyEvent.VK_ENTER){

switch(code){

case 0:

y=x+Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 1:

y=x-Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 2:

y=x*Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 3:

y=x/Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

}

}

}

public void keyReleased(KeyEvent arg0) {

// TODO Auto-generated method stub

}

public void keyTyped(KeyEvent arg0) {

// TODO Auto-generated method stub

}

}

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();

}

}

用Java编写一个简单的计算器程序

import java.awt.*;

import java.awt.event.*;

public class CalcAppDemo extends Frame{

private TextField t_result;

private Panel p_main; //主面板

private Panel p_num; //数字面板

private Panel p_oper; //操作符面板

private Panel p_show; //显示面板

private Button b_num[]; //数字按钮

private Button b_oper[]; //操作符面板

public CalcAppDemo(String title){

setTitle(title);

t_result = new TextField("0.0", 21);

p_main = new Panel();

p_num = new Panel();

p_oper = new Panel();

p_show = new Panel();

p_main.setLayout(new BorderLayout());

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

p_oper.setLayout(new GridLayout(4, 2, 1, 1));

b_num = new Button[12];

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

{

b_num[i] = new Button(new Integer(i+1).toString());

}

b_num[9] = new Button("0");

b_num[10] = new Button("cls");

b_num[11] = new Button(".");

for(int i=0; i12; i++)

{

p_num.add(b_num[i]);

}

b_oper = new Button[8];

b_oper[0] = new Button("+");

b_oper[1] = new Button("-");

b_oper[2] = new Button("*");

b_oper[3] = new Button("/");

b_oper[4] = new Button("pow");

b_oper[5] = new Button("sqrt");

b_oper[6] = new Button("+/-");

b_oper[7] = new Button("=");

for(int i=0; i8; i++) //

{

p_oper.add(b_oper[i]);

}

t_result.setEditable(false);

p_show.add(t_result, BorderLayout.NORTH);

p_main.add(p_show, BorderLayout.NORTH);

p_main.add(p_num, BorderLayout.WEST);

p_main.add(p_oper, BorderLayout.EAST);

this.add(p_main, BorderLayout.CENTER);

setSize(400, 400);

setResizable(false);

pack();

this.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e)

{

System.exit(0);

}

});

ButtonListener b1 = new ButtonListener();

for(int i=0; i12; i++)

{

b_num[i].addActionListener(b1);

}

for(int i=0; i8; i++)

{

b_oper[i].addActionListener(b1);

}

}

class ButtonListener implements ActionListener

{

private String lastOp; //存储上一此操作符

private String strVal; //存储数字对应的字符串

private double total; //总数

private double number; //存储新输入的数

private boolean firsttime; //判断是否第一次按下的是操作符按钮

private boolean operatorPressed;//判断是否已经按过操作符按钮

ButtonListener()

{

firsttime = true;

strVal = "";

}

//事件处理器

public void actionPerformed(ActionEvent e)

{

String s = ((Button)e.getSource()).getLabel().trim();

if(Character.isDigit(s.charAt(0)))

{//判断是操作数还是操作符

handleNumber(s);

}

else

{

calculate(s);

}

}

//判断是一元操作符还是二元操作符,并根据操作符类型做计算

void calculate(String op)

{

operatorPressed = true;

if(firsttime! isUnary(op))

{

total = getNumberOnDisplay();

firsttime = false;

}

if(isUnary(op))

{

handleUnaryOp(op);

}

else if(lastOp != null)

{

handleBinaryOp(lastOp);

}

if(! isUnary(op))

{

lastOp = op;

}

}

//判断是否一元操作符

boolean isUnary(String s)

{

return s.equals("=")

||s.equals("cls")||s.equals("sqrt")

||s.equals("+/-")||s.equals(".");

}

//处理一元操作符

void handleUnaryOp(String op)

{

if(op.equals("+/-"))

{//

number = negate(getNumberOnDisplay() + "");

t_result.setText("");

t_result.setText(number + "");

return;

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

{

handleDecPoint();

return;

}else if(op.equals("sqrt"))

{

number = Math.sqrt(getNumberOnDisplay());

t_result.setText("");

t_result.setText(number + "");

return;

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

{//

if(lastOp!= null !isUnary(lastOp))

{

handleBinaryOp(lastOp);

}

lastOp = null;

firsttime = true;

return;

}else

{

clear();

}

}

//处理二元运算符

void handleBinaryOp(String op)

{

if(op.equals("+"))

{

total +=number;

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

{

total -=number;

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

{

total *=number;

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

{

try

{

total /=number;

}catch(ArithmeticException ae){}

}else if(op.equals("pow"))

total = Math.pow(total, number);

//t_result.setText("");

lastOp = null;

// strVal = "";

number = 0;

t_result.setText(total + "");

}

//该方法用于处理数字按钮

void handleNumber(String s)

{

if(!operatorPressed)

{

strVal += s;

}else

{

operatorPressed = false;

strVal = s;

}

//

number = new Double(strVal).doubleValue();

t_result.setText("");

t_result.setText(strVal);

}

//该方法用于按下"."按钮

void handleDecPoint()

{

operatorPressed = false;

//

if(strVal.indexOf(".")0)

{

strVal += ".";

}

t_result.setText("");

t_result.setText(strVal);

}

//该方法用于将一个数求反

double negate(String s)

{

operatorPressed = false;

//如果是一个整数,去掉小数点后面的0

if(number == (int)number)

{

s = s.substring(0,s.indexOf("."));

}

//如果无"-"增加在该数的前面

if(s.indexOf("-")0)

{

strVal = "-" + s;

}

else

{

strVal = s.substring(1);

}

return new Double(strVal).doubleValue();

}

//将显示框中的值转换成Double

double getNumberOnDisplay()

{

return new Double(t_result.getText()).doubleValue();

}

//清除屏幕并设置所有的标识

void clear()

{

firsttime = true;

lastOp = null;

strVal = "";

total = 0;

number = 0;

t_result.setText("0");

}

}

public static void main(String[] args) {

CalcAppDemo c = new CalcAppDemo("简单的计算器程序");

c.setVisible(true);

}

}

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();