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如何用JAVA语言编写计算器小程序？
具体代码如下：
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import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Calculator extends JFrame implements ActionListener {
private JFrame jf;
private JButton[] allButtons;
private JButton clearButton;
private JTextField jtf;
public Calculator() {
//对图形组件实例化
jf=new JFrame("任静的计算器1.0：JAVA版");
jf.addWindowListener(new WindowAdapter(){
public void windowClosing(){
System.exit(0);
}
});
allButtons=new JButton[16];
clearButton=new JButton("清除");
jtf=new JTextField(25);
jtf.setEditable(false);
String str="123+456-789*0.=/";
for(int i=0;iallButtons.length;i++){
allButtons[i]=new JButton(str.substring(i,i+1));
}
}
public void init(){
//完成布局
jf.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(jtf);
for(int i=0;i16;i++){
centerPanel.add(allButtons[i]);
}
southPanel.add(clearButton);
jf.add(northPanel,BorderLayout.NORTH);
jf.add(centerPanel,BorderLayout.CENTER);
jf.add(southPanel,BorderLayout.SOUTH);
addEventHandler();
}
//添加事件监听
public void addEventHandler(){
jtf.addActionListener(this);
for(int i=0;iallButtons.length;i++){
allButtons[i].addActionListener(this);
}
clearButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
Calculator.this.jtf.setText("");
}
});
}
//事件处理
public void actionPerformed(ActionEvent e) {
//在这里完成事件处理 使计算器可以运行
String action=e.getActionCommand();
if(action=="+"||action=="-"||action=="*"||action=="/"){
}
}
public void setFontAndColor(){
Font f=new Font("宋体",Font.BOLD,24);
jtf.setFont(f);
jtf.setBackground(new Color(0x8f,0xa0,0xfb));
for(int i=0;i16;i++){
allButtons[i].setFont(f);
allButtons[i].setForeground(Color.RED);
}
}
public void showMe(){
init();
setFontAndColor();
jf.pack();
jf.setVisible(true);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args){
new Calculator().showMe();
}
}
java 计算器代码
import javax.swing.*;
import javax.swing.border.Border;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.HashMap;
/**
* 我的计算器。Cheshi 继承于 JFrame，是计算器的界面
c*/
public class Cheshi extends JFrame {
private Border border = BorderFactory.createEmptyBorder(5, 5, 5, 5);
private JTextField textbox = new JTextField("0");
private CalculatorCore core = new CalculatorCore();
private ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
JButton b = (JButton) e.getSource();
String label = b.getText();
String result = core.process(label);
textbox.setText(result);
}
};
public Cheshi(String title) throws HeadlessException {
super(title); // 调用父类构造方法
setupFrame(); // 调整窗体属性
setupControls(); // 创建控件
}
private void setupControls() {
setupDisplayPanel(); // 创建文本面板
setupButtonsPanel(); // 创建按钮面板
}
// 创建按钮面板并添加按钮
private void setupButtonsPanel() {
JPanel panel = new JPanel();
panel.setBorder(border);
panel.setLayout(new GridLayout(4, 5, 3, 3));
createButtons(panel, new String[]{
"7", "8", "9", "+", "C",
"4", "5", "6", "-", "CE",
"1", "2", "3", "*", "", // 空字符串表示这个位置没有按钮
"0", ".", "=", "/", ""
});
this.add(panel, BorderLayout.CENTER);
}
/**
* 在指定的面板上创建按钮
*
* @param panel 要创建按钮的面板
* @param labels 按钮文字
*/
private void createButtons(JPanel panel, String[] labels) {
for (String label : labels) {
// 如果 label 为空，则表示创建一个空面板。否则创建一个按钮。
if (label.equals("")) {
panel.add(new JPanel());
} else {
JButton b = new JButton(label);
b.addActionListener(listener); // 为按钮添加侦听器
panel.add(b);
}
}
}
// 设置显示面板，用一个文本框来作为计算器的显示部分。
private void setupDisplayPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.setBorder(border);
setupTextbox();
panel.add(textbox, BorderLayout.CENTER);
this.add(panel, BorderLayout.NORTH);
}
// 调整文本框
private void setupTextbox() {
textbox.setHorizontalAlignment(JTextField.RIGHT); // 文本右对齐
textbox.setEditable(false); // 文本框只读
textbox.setBackground(Color.white); // 文本框背景色为白色
}
// 调整窗体
private void setupFrame() {
this.setDefaultCloseOperation(EXIT_ON_CLOSE); // 当窗体关闭时程序结束
this.setLocation(100, 50); // 设置窗体显示在桌面上的位置
this.setSize(300, 200); // 设置窗体大小
this.setResizable(false); // 窗体大小固定
}
// 程序入口
public static void main(String[] args) throws Exception {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
Cheshi frame = new Cheshi("我的计算器");
frame.setVisible(true); // 在桌面上显示窗体
}
}
/**
* 计算器核心逻辑。这个逻辑只能处理 1~2 个数的运算。
*/
class CalculatorCore {
private String displayText = "0"; // 要显示的文本
boolean reset = true;
private BigDecimal number1, number2;
private String operator;
private HashMapString, Operator operators = new HashMapString, Operator();
private HashMapString, Processor processors = new HashMapString, Processor();
CalculatorCore() {
setupOperators();
setupProcessors();
}
// 为每种命令添加处理方式
private void setupProcessors() {
processors.put("[0-9]", new Processor() {
public void calculate(String command) {
numberClicked(command);
}
});
processors.put("\\.", new Processor() {
public void calculate(String command) {
dotClicked();
}
});
processors.put("=", new Processor() {
public void calculate(String command) {
equalsClicked();
}
});
processors.put("[+\\-*/]", new Processor() {
public void calculate(String command) {
operatorClicked(command);
}
});
processors.put("C", new Processor() {
public void calculate(String command) {
clearClicked();
}
});
processors.put("CE", new Processor() {
public void calculate(String command) {
clearErrorClicked();
}
});
}
// 为每种 operator 添加处理方式
private void setupOperators() {
operators.put("+", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.add(number2);
}
});
operators.put("-", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.subtract(number2);
}
});
operators.put("*", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.multiply(number2);
}
});
operators.put("/", new Operator() {
public BigDecimal process(BigDecimal number1, BigDecimal number2) {
return number1.divide(number2, 30, RoundingMode.HALF_UP);
}
});
}
// 根据命令处理。这里的命令实际上就是按钮文本。
public String process(String command) {
for (String pattern : processors.keySet()) {
if (command.matches(pattern)) {
processors.get(pattern).calculate(command);
break;
}
}
return displayText;
}
// 当按下 CE 时
private void clearErrorClicked() {
if (operator == null) {
number1 = null;
} else {
number2 = null;
}
displayText = "0";
reset = true;
}
// 当按下 C 时，将计算器置为初始状态。
private void clearClicked() {
number1 = null;
number2 = null;
operator = null;
displayText = "0";
reset = true;
}
// 当按下 = 时
private void equalsClicked() {
calculateResult();
number1 = null;
number2 = null;
operator = null;
reset = true;
}
// 计算结果
private void calculateResult() {
number2 = new BigDecimal(displayText);
Operator oper = operators.get(operator);
if (oper != null) {
BigDecimal result = oper.process(number1, number2);
displayText = result.toString();
}
}
// 当按下 +-*/ 时（这里也可以扩展成其他中间操作符）
private void operatorClicked(String command) {
if (operator != null) {
calculateResult();
}
number1 = new BigDecimal(displayText);
operator = command;
reset = true;
}
// 当按下 . 时
private void dotClicked() {
if (displayText.indexOf(".") == -1) {
displayText += ".";
} else if (reset) {
displayText = "0.";
}
reset = false;
}
// 当按下 0-9 时
private void numberClicked(String command) {
if (reset) {
displayText = command;
} else {
displayText += command;
}
reset = false;
}
// 运算符处理接口
interface Operator {
BigDecimal process(BigDecimal number1, BigDecimal number2);
}
// 按钮处理接口
interface Processor {
void calculate(String command);
}
}
java编程，用代码实现计算器类（Calculator）
public class Calculator {
private int number1;
private int number2;
public Calculator(int number1, int number2) {
this.number1 = number1;
this.number2 = number2;
}
public double add() {
return number1 + number2;
}
public double subtract() {
return number1 - number2;
}
public double multiple() {
return number1 * number2;
}
public double divide() {
if(number2 == 0) {
return 0;
}
return number1 / number2;
}
}
public class TestCalculator {
public static void main(String[] args) {
Calculator calculator = new Calculator(5, 2);
System.out.println(calculator.add());
System.out.println(calculator.subtract());
System.out.println(calculator.multiple());
System.out.println(calculator.divide());
}
}
文章题目：java类计算器代码 java编写计算器类
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