本文目錄一覽：
java編寫計算器！
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;//計算結果顯示區
private String lastCommand;//保存+,-,*,/,=命令
private double result;//保存計算結果
private boolean start;//判斷是否為數字的開始
public Calculator() {
super(“計算器”);
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編程迷你計算器
現在是一段核心程序，只有單位數的四則運算，需要實現多位數運算和小數點功能，最好還有正負號。萬分感謝！
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計算器
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,”確定要關閉程序嗎?”,”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 編寫計算器 要代碼最簡單的
學java的時候自己編的，很簡單，能夠連續輸入計算式後進行計算
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;
/**簡易計算器，能夠進行簡單的計算
*
* @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=””;//保存結果
StringBuilder sb = new StringBuilder();//保存要進行的計算式
int x = 0; //用來判斷上一次的事件類型
String str = “123+456-789*0.=/”;
ArrayListString arrayList = new ArrayListString();//保存計算式，通過方法進行運算
public CalculatorA(){
frame = new JFrame(“我的計算器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);
}
//設置輸入字體
public void setFondAndColor(){
field.setFont(new Font(“宋體”,Font.BOLD,24));
field.setBackground(new Color(100,200,200));
field.setForeground(Color.RED);
//設置字體從右起始
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();//取得當前事件返回的值
if(“0123456789.”.indexOf(str)!=-1){
if(x == 0){ //當x為0時表示還沒有進行輸入
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(“數據格式異常”);
x = 0;
}
}
else if(x == 2){
field.setText(“數據格式錯誤…..”);
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(“數據格式異常”);
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)));
//本地的數據格式
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;
}
//對數字字符串進行排除不必要符號
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編寫一個簡單的計算器程序
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; //數字面板
private Panel p_oper; //操作符面板
private Panel p_show; //顯示面板
private Button b_num[]; //數字按鈕
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; //存儲上一此操作符
private String strVal; //存儲數字對應的字符串
private double total; //總數
private double number; //存儲新輸入的數
private boolean firsttime; //判斷是否第一次按下的是操作符按鈕
private boolean operatorPressed;//判斷是否已經按過操作符按鈕
ButtonListener()
{
firsttime = true;
strVal = “”;
}
//事件處理器
public void actionPerformed(ActionEvent e)
{
String s = ((Button)e.getSource()).getLabel().trim();
if(Character.isDigit(s.charAt(0)))
{//判斷是操作數還是操作符
handleNumber(s);
}
else
{
calculate(s);
}
}
//判斷是一元操作符還是二元操作符，並根據操作符類型做計算
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;
}
}
//判斷是否一元操作符
boolean isUnary(String s)
{
return s.equals(“=”)
||s.equals(“cls”)||s.equals(“sqrt”)
||s.equals(“+/-“)||s.equals(“.”);
}
//處理一元操作符
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();
}
}
//處理二元運算符
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 + “”);
}
//該方法用於處理數字按鈕
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);
}
//該方法用於按下”.”按鈕
void handleDecPoint()
{
operatorPressed = false;
//
if(strVal.indexOf(“.”)0)
{
strVal += “.”;
}
t_result.setText(“”);
t_result.setText(strVal);
}
//該方法用於將一個數求反
double negate(String s)
{
operatorPressed = false;
//如果是一個整數，去掉小數點後面的0
if(number == (int)number)
{
s = s.substring(0,s.indexOf(“.”));
}
//如果無”-“增加在該數的前面
if(s.indexOf(“-“)0)
{
strVal = “-” + s;
}
else
{
strVal = s.substring(1);
}
return new Double(strVal).doubleValue();
}
//將顯示框中的值轉換成Double
double getNumberOnDisplay()
{
return new Double(t_result.getText()).doubleValue();
}
//清除屏幕並設置所有的標識
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(“簡單的計算器程序”);
c.setVisible(true);
}
}
java計算器的源代碼
import java.awt.*;
import java.awt.event.*;
import java.lang.*;
import javax.swing.*;
public class Counter extends Frame
{
//聲明三個面板的布局
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;//顯示屏所顯示的字符串
double x,y;//x和y都是運算數
int z;//Z表示單擊了那一個運算符.0表示”+”,1表示”-“,2表示”*”,3表示”/”
static double m;//記憶的數字
public Counter()
{
gl1=new GridLayout(1,4,10,0);//實例化三個面板的布局
gl2=new GridLayout(4,1,0,15);
gl3=new GridLayout(4,5,10,15);
tf1=new JTextField(27);//顯示屏
tf1.setHorizontalAlignment(JTextField.RIGHT);
tf1.setEnabled(false);
tf1.setText(“0”);
tf2=new TextField(10);//顯示記憶的索引值
tf2.setEditable(false);
//實例化所有按鈕、設置其前景色並註冊監聽器
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());
//實例化四個面板
p0=new Panel();
p1=new Panel();
p2=new Panel();
p3=new Panel();
//創建一個空字符串緩衝區
str=new StringBuffer();
//添加面板p0中的組件和設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中的組件和設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中的組件並設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中的組件並設置其在框架中的位置和大小
p3.setLayout(gl3);//設置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);
//設置框架中的布局為空布局並添加4個面板
setLayout(null);
add(p0);
add(p1);
add(p2);
add(p3);
setResizable(false);//禁止調整框架的大小
//匿名類關閉窗口
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e1)
{
System.exit(0);
}
});
setBackground(Color.lightGray);
setBounds(100,100,320,280);
setVisible(true);
}
//構造監聽器
class Bt implements ActionListener
{
public void actionPerformed(ActionEvent e2)
{
try{
if(e2.getSource()==b1)//選擇”CE”清零
{
tf1.setText(“0”);//把顯示屏清零
str.setLength(0);//清空字符串緩衝區以準備接收新的輸入運算數
}
else if(e2.getSource()==b2)//選擇”C”清零
{
tf1.setText(“0”);//把顯示屏清零
str.setLength(0);
}
else if(e2.getSource()==b23)//單擊”+/-“選擇輸入的運算數是正數還是負數
{
x=Double.parseDouble(tf1.getText().trim());
tf1.setText(“”+(-x));
}
else if(e2.getSource()==b25)//單擊加號按鈕獲得x的值和z的值並清空y的值
{
x=Double.parseDouble(tf1.getText().trim());
str.setLength(0);//清空緩衝區以便接收新的另一個運算數
y=0d;
z=0;
}
else if(e2.getSource()==b20)//單擊減號按鈕獲得x的值和z的值並清空y的值
{
x=Double.parseDouble(tf1.getText().trim());
str.setLength(0);
y=0d;
z=1;
}
else if(e2.getSource()==b15)//單擊乘號按鈕獲得x的值和z的值並清空y的值
{
x=Double.parseDouble(tf1.getText().trim());
str.setLength(0);
y=0d;
z=2;
}
else if(e2.getSource()==b10)//單擊除號按鈕獲得x的值和z的值並空y的值
{
x=Double.parseDouble(tf1.getText().trim());
str.setLength(0);
y=0d;
z=3;
}
else if(e2.getSource()==b26)//單擊等號按鈕輸出計算結果
{
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)//單擊”.”按鈕輸入小數
{
if(tf1.getText().trim().indexOf(′.′)!=-1)//判斷字符串中是否已經包含了小數點
{
}
else//如果沒數點有小
{
if(tf1.getText().trim().equals(“0”))//如果初時顯示為0
{
str.setLength(0);
tf1.setText((str.append(“0″+e2.getActionCommand())).toString());
}
else if(tf1.getText().trim().equals(“”))//如果初時顯示為空則不做任何操作
{
}
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(“數字格式異常”);
if(x0)
tf1.setText(“負數沒有平方根”);
else
tf1.setText(“”+Math.sqrt(x));
str.setLength(0);
y=0d;
}
else if(e2.getSource()==b16)//單擊了”%”按鈕
{
x=Double.parseDouble(tf1.getText().trim());
tf1.setText(“”+(0.01*x));
str.setLength(0);
y=0d;
}
else if(e2.getSource()==b21)//單擊了”1/X”按鈕
{
x=Double.parseDouble(tf1.getText().trim());
if(x==0)
{
tf1.setText(“除數不能為零”);
}
else
{
tf1.setText(“”+(1/x));
}
str.setLength(0);
y=0d;
}
else if(e2.getSource()==b3)//MC為清除內存
{
m=0d;
tf2.setText(“”);
str.setLength(0);
}
else if(e2.getSource()==b4)//MR為重新調用存儲的數據
{
if(tf2.getText().trim()!=””)//有記憶數字
{
tf1.setText(“”+m);
}
}
else if(e2.getSource()==b5)//MS為存儲顯示的數據
{
m=Double.parseDouble(tf1.getText().trim());
tf2.setText(“M”);
tf1.setText(“0”);
str.setLength(0);
}
else if(e2.getSource()==b6)//M+為將顯示的數字與已經存儲的數據相加要查看新的數字單擊MR
{
m=m+Double.parseDouble(tf1.getText().trim());
}
else//選擇的是其他的按鈕
{
if(e2.getSource()==b22)//如果選擇的是”0″這個數字鍵
{
if(tf1.getText().trim().equals(“0”))//如果顯示屏顯示的為零不做操作
{
}
else
{
tf1.setText(str.append(e2.getActionCommand()).toString());
y=Double.parseDouble(tf1.getText().trim());
}
}
else if(e2.getSource()==b0)//選擇的是「BackSpace」按鈕
{
if(!tf1.getText().trim().equals(“0”))//如果顯示屏顯示的不是零
{
if(str.length()!=1)
{
tf1.setText(str.delete(str.length()-1,str.length()).toString());//可能拋出字符串越界異常
}
else
{
tf1.setText(“0”);
str.setLength(0);
}
}
y=Double.parseDouble(tf1.getText().trim());
}
else//其他的數字鍵
{
tf1.setText(str.append(e2.getActionCommand()).toString());
y=Double.parseDouble(tf1.getText().trim());
}
}
}
catch(NumberFormatException e){
tf1.setText(“數字格式異常”);
}
catch(StringIndexOutOfBoundsException e){
tf1.setText(“字符串索引越界”);
}
}
}
public static void main(String args[])
{
new Counter();
原創文章，作者：JFIC，如若轉載，請註明出處：https://www.506064.com/zh-hk/n/146742.html
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