本文目录一览：
- 1、如何用java编写一个简单的计算器，只要能进行最基本的加减乘除运算就可以了，本人急用，简单易懂即可，大
- 2、JAVA 编写计算器 要代码最简单的
- 3、求JAVA编写的 简易计算器程序，附上注释
- 4、如何用java写一个简单的计算器
- 5、用JAVA编写一个简单的计算器，要求如下
- 6、用Java编写一个简单的计算器程序
如何用java编写一个简单的计算器，只要能进行最基本的加减乘除运算就可以了，本人急用，简单易懂即可，大
简单的啊，我有个自己编的完美的，不过给你改成简单的吧。有注释。
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
import java.text.*;
public class Calculator extends JFrame implements ActionListener
{
int m=0,i,n=0;
float sum=0,s1,s2,equ;
String v="";
JPanel delete_main = new JPanel();
JPanel delete = new JPanel();
JPanel buttons = new JPanel();
JTextField text = new JTextField("0");
JButton backspace = new JButton("Backspace");
JButton c = new JButton("C");
JButton ce = new JButton("CE");
JButton bt1= new JButton("1");
JButton bt2= new JButton("2");
JButton bt3= new JButton("3");
JButton bt4= new JButton("+");
JButton bt5 = new JButton("4");
JButton bt6= new JButton("5");
JButton bt7= new JButton("6");
JButton bt8= new JButton("-");
JButton bt9= new JButton("7");
JButton bt10= new JButton("8");
JButton bt11= new JButton("9");
JButton bt12= new JButton("*");
JButton bt13= new JButton("0");
JButton bt14= new JButton(".");
JButton bt15= new JButton("=");
JButton bt16= new JButton("/");
public Calculator()
{
super("简易计算器--超人不会飞荣誉出品");
delete.setLayout(new GridLayout(1, 3, 15, 15));
delete.add(backspace);
delete.add(c);
delete.add(ce);
delete.setBorder(new LineBorder(delete.getBackground(), 5));//添加边框
c.addActionListener(this);
ce.addActionListener(this);
backspace.addActionListener(this);
text.setFont(new Font("宋体", Font.BOLD +Font.ITALIC, 20));
// 设置显示字体
text.setBackground(Color.getHSBColor(44, 3, 87));
text.setBorder(new LineBorder(Color.ORANGE, 1));
text.setHorizontalAlignment(SwingConstants.RIGHT); // 设置鼠标靠右
text.setEditable(false); // 屏蔽键盘输入，防止非法字符
delete_main.setLayout(new GridLayout(2, 1, 10, 10));
delete_main.add(text, BorderLayout.NORTH);
delete_main.add(delete, BorderLayout.SOUTH);
buttons.setLayout(new GridLayout(4, 5, 10, 20));
bt1.addActionListener(this); // 为各个按钮添加事件监听
buttons.add(bt1);
bt2.addActionListener(this);
buttons.add(bt2);
bt3.addActionListener(this);
buttons.add(bt3);
bt4.addActionListener(this);
buttons.add(bt4);
bt5.addActionListener(this);
buttons.add(bt5);
bt6.addActionListener(this);
buttons.add(bt6);
bt7.addActionListener(this);
buttons.add(bt7);
bt8.addActionListener(this);
buttons.add(bt8);
bt9.addActionListener(this);
buttons.add(bt9);
bt10.addActionListener(this);
buttons.add(bt10);
bt11.addActionListener(this);
buttons.add(bt11);
bt12.addActionListener(this);
buttons.add(bt12);
bt13.addActionListener(this);
buttons.add(bt13);
bt14.addActionListener(this);
buttons.add(bt14);
bt15.addActionListener(this);
buttons.add(bt15);
bt16.addActionListener(this);
buttons.add(bt16);
buttons.setBorder(new LineBorder(delete.getBackground(), 5));//边框
this.setLayout(new BorderLayout());
this.add(delete_main, BorderLayout.NORTH);
this.add(buttons, BorderLayout.SOUTH);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //添加关闭窗口事件监听器
pack(); //自动设置窗体大小
setResizable(false); // 设置面板大小不可变
setVisible(true);
Toolkit tk = this.getToolkit();
Dimension de = tk.getScreenSize();
setBounds((de.width - this.getWidth()) / 2,(de.height - this.getHeight()) / 2, this.getWidth(), this.getHeight());
//使之居于屏幕正中央
}
public void actionPerformed(ActionEvent e)
{ //事件响应
//Object source = e.getSource();
if(e.getSource()==backspace) //退格键
{
v=v.substring(0,v.length() - 1);
text.setText(v);
}
if(e.getSource()==c||e.getSource()==ce) //清空键
{
m=0;
sum=0;
v="";s1=0;s2=0;i=0;
text.setText("0");
}
if(e.getSource()==bt1)
{
if(m==1)
v="";
v=v+"1";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt2)
{
if(m==1)
v="";
v=v+"2";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt3)
{
if(m==1)
v="";
v=v+"3";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt4) // +按钮
{
if(n==1) //如果按之前按了0~9数字键，就运算
{
sum=Float.parseFloat(v);
}
else //如果按之前没按0~9数字键，直接按了运算符，不做任何操作
{
}
i=1;
m=1;n=0;
}
if(e.getSource()==bt5)
{
if(m==1)
v="";
v=v+"4";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt6)
{
if(m==1)
v="";
v=v+"5";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt7)
{
if(m==1)
v="";
v=v+"6";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt8) // -按钮
{
if(n==1)
{
sum=Float.parseFloat(v);
}
else
{
}
i=2;
m=1;n=0;
}
if(e.getSource()==bt9)
{
if(m==1)
v="";
v=v+"7";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt10)
{
if(m==1)
v="";
v=v+"8";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt11)
{
if(m==1)
v="";
v=v+"9";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt12) //*按钮
{
if(n==1)
{
sum=Float.parseFloat(v);
}
else
{
}
i=3;
m=1;n=0;
}
if(e.getSource()==bt13)
{
if(m==1)
v="";
v=v+"0";
text.setText(v);
m=0;n=1;
}
if(e.getSource()==bt14)
{
}
if(e.getSource()==bt15) //等于按钮
{
if(m==1) // 如果输入了+=等非法输入，不做任何操作
{ }
else
{
s1=sum;
s2=Float.parseFloat(v);
switch(i)
{
case 0: //如果按过数字键后直接按等号，直接输出
equ=Float.parseFloat(v);
break;
case 1:
equ=s1+s2;
break;
case 2:
equ=s1-s2;
break;
case 3:
equ=s1*s2;
break;
case 4:
equ=s1/s2;
break;
}
sum=0;v=""; //清空运算数
v=String.valueOf(equ);
text.setText(String.valueOf(equ));
i=0;
}
}
if(e.getSource()==bt16) // 除按钮
{
if(n==1)
{
sum=Float.parseFloat(v);
}
else
{
}
i=4;
m=1;n=0;
}
}
public static void main(String[] args)
{
Calculator bt=new Calculator();
}
}
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();
}
}
求JAVA编写的 简易计算器程序，附上注释
1、首先准备好软件即eclipse和java，下载安装完成后打开eclipse。
2、点击左上角的file 新建一个project。
3、给project取一个名字，其他的选项都是默认然后点击finish。
4、接下来是新建一个class。
5、在给class取名字的时候注意用英文名的首字母要大写。完成后点击finish。
6、这就是开始写代码的工作台，将代码写在绿字下。
7、这就是第一个hello world程序。
如何用java写一个简单的计算器
import java.awt.Button;
import java.awt.Color;
import java.awt.Frame;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.TextField;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class Calculator extends WindowAdapter implements MouseListener {
private String first;
private String second;
private String operator;
private Button zero = new Button("0");
private Button one = new Button("1");
private Button two = new Button("2");
private Button three = new Button("3");
private Button four = new Button("4");
private Button five = new Button("5");
private Button six = new Button("6");
private Button seven = new Button("7");
private Button eight = new Button("8");
private Button nine = new Button("9");
private Button decimal = new Button(".");
private Button equal = new Button("=");
private Button add = new Button("+");
private Button sub = new Button("-");
private Button mul = new Button("*");
private Button div = new Button("/");
private TextField input = new TextField();
private Button CE = new Button("CE");
private Button DEL = new Button("Del");
public static void main(String[] args) {
new Calculator();
}
public Calculator(){
Frame f = new Frame("Calculator");
f.add("North", input);
Panel keys = new Panel();
f.add(keys, "Center");
keys.setLayout(new GridLayout(4, 4));
keys.add(seven);
keys.add(eight);
keys.add(nine);
keys.add(add);
keys.add(four);
keys.add(five);
keys.add(six);
keys.add(sub);
keys.add(one);
keys.add(two);
keys.add(three);
keys.add(mul);
keys.add(zero);
keys.add(decimal);
keys.add(equal);
keys.add(div);
zero.addMouseListener(this);
one.addMouseListener(this);
two.addMouseListener(this);
three.addMouseListener(this);
four.addMouseListener(this);
five.addMouseListener(this);
six.addMouseListener(this);
seven.addMouseListener(this);
eight.addMouseListener(this);
nine.addMouseListener(this);
add.addMouseListener(this);
sub.addMouseListener(this);
div.addMouseListener(this);
mul.addMouseListener(this);
equal.addMouseListener(this);
decimal.addMouseListener(this);
Panel addtionalPanel = new Panel();
addtionalPanel.setLayout(new GridLayout(1, 2));
addtionalPanel.add(CE);
addtionalPanel.add(DEL);
CE.setBackground(Color.green);
DEL.setBackground(Color.cyan);
CE.addMouseListener(this);
DEL.addMouseListener(this);
f.add("South", addtionalPanel);
f.addWindowListener(this);
f.setVisible(true);
f.setLocation(200, 300);
f.setSize(200, 200);
}
public void windowClosing(WindowEvent e) {
System.exit(0);
}
public void mouseClicked(MouseEvent e) {
Button btn = (Button) e.getSource();
String key = btn.getActionCommand().trim();
if(btn == one || btn == two || btn == three || btn == zero
|| btn == four || btn == five || btn == six
|| btn == seven || btn == eight || btn == nine){
if(isBlank(operator)){
if(isBlank(first)){
first = key;
}else{
first += key;
}
input.setText(first);
}else{
if(isBlank(second)){
second = key;
}else{
second += key;
}
input.setText(second);
}
}else if(btn == decimal){
if(isBlank(operator)){
if(isBlank(first)){
first = "0.";
input.setText(first);
}else{
if(first.indexOf(".") == -1){
first += ".";
input.setText(first);
}
}
}else{
if(isBlank(second)){
second = "0.";
input.setText(second);
}else{
if(second.indexOf(".") == -1){
second += ".";
input.setText(second);
}
}
}
}else if(btn == equal){
if(!isBlank(second) !isBlank(first) !isBlank(operator)){
double result = 0.0D;
if(operator.equals("+")){
result = Double.parseDouble(first) + Double.parseDouble(second);
}else if(operator.equals("-")){
result = Double.parseDouble(first) - Double.parseDouble(second);
}else if(operator.equals("*")){
result = Double.parseDouble(first) * Double.parseDouble(second);
}else if(operator.equals("/")){
result = Double.parseDouble(first) / Double.parseDouble(second);
}
int value = (int)Math.round(result);
if(value == result){
input.setText(String.valueOf(value));
}else{
input.setText(String.valueOf(result));
}
first = String.valueOf(result);
second = null;
operator = null;
}
}else if(btn == add || btn == sub || btn == div || btn == mul){
if(!isBlank(first)){
if(!isBlank(operator) !isBlank(second)){
if(operator.equals("+")){
first = String.valueOf(Double.parseDouble(first) + Double.parseDouble(second));
}else if(operator.equals("-")){
first = String.valueOf(Double.parseDouble(first) - Double.parseDouble(second));
}else if(operator.equals("*")){
first = String.valueOf(Double.parseDouble(first) * Double.parseDouble(second));
}else if(operator.equals("/")){
first = String.valueOf(Double.parseDouble(first) / Double.parseDouble(second));
}
second = null;
}
operator = key;
}
}else if(btn == CE){
first = null;
second = null;
operator = null;
input.setText(null);
}else if(btn == DEL){
if(isBlank(operator)){
if(!isBlank(first)){
first = first.substring(0, first.length() -1);
input.setText(first);
}
}else{
if(!isBlank(second)){
second = second.substring(0, second.length() -1);
input.setText(second);
}
}
}
}
private boolean isBlank(String str){
return str == null || str.trim().equals("");
}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
}
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);
}
}
