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Java实现简易计算器程序
2023-06-15 19:04:42 深夜i     --     --
Java 计算器 程序设计

作为一名程序员，我们经常需要开发一些小工具来帮助我们完成日常的任务。而计算器恰好是我们日常工作中必不可少的工具之一。本文将教你如何使用Java语言编写一个简易计算器程序，以方便你日常的计算操作。

在Java中，我们可以使用JFrame类来创建一个窗体，使用JPanel来创建计算器的界面布局。然后我们可以定义各种按钮来完成不同的计算操作。最后，我们可以将计算结果输出在文本框中。以下是Java代码实现：



import java.awt.*;


import java.awt.event.*;


import javax.swing.*;


class Calculator extends JFrame implements ActionListener {


private JPanel mainPanel;


private JPanel controlPanel;


private JTextField resultField;


private JButton addButton, subButton, mulButton, divButton, equalButton;


private JButton[] numButtons;


private String result = "0";


private String lastCommand = "=";


private boolean start = true;


public Calculator() {


mainPanel = new JPanel();


mainPanel.setLayout(new BorderLayout());


resultField = new JTextField(result, 20);


resultField.setHorizontalAlignment(JTextField.RIGHT);


resultField.setEditable(false);


mainPanel.add(resultField, BorderLayout.NORTH);


controlPanel = new JPanel();


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


numButtons = new JButton[10];


for (int i = 0; i < 10; i++) {


numButtons[i] = new JButton(String.valueOf(i));


numButtons[i].addActionListener(this);


controlPanel.add(numButtons[i]);


}


addButton = new JButton("+");


addButton.addActionListener(this);


controlPanel.add(addButton);


subButton = new JButton("-");


subButton.addActionListener(this);


controlPanel.add(subButton);


mulButton = new JButton("*");


mulButton.addActionListener(this);


controlPanel.add(mulButton);


divButton = new JButton("/");


divButton.addActionListener(this);


controlPanel.add(divButton);


equalButton = new JButton("=");


equalButton.addActionListener(this);


controlPanel.add(equalButton);


mainPanel.add(controlPanel, BorderLayout.CENTER);


this.add(mainPanel);


this.setTitle("简易计算器程序");


this.setSize(250, 250);


this.setLocationRelativeTo(null);


this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


this.setVisible(true);


}


public void actionPerformed(ActionEvent e) {


String command = e.getActionCommand();


if (command.charAt(0) >= '0' && command.charAt(0) <= '9' || command.equals(".")) {


if (start)


result = "";


start = false;


result += command;


resultField.setText(result);


} else {


if (start) {


if (command.equals("-")) {


result = command;


resultField.setText(result);


start = false;


} else


lastCommand = command;


} else {


calculate(Double.parseDouble(result));


lastCommand = command;


start = true;


}


}


}


public void calculate(double x) {


if (lastCommand.equals("+")) {


result = String.valueOf(Double.parseDouble(result) + x);


} else if (lastCommand.equals("-")) {


result = String.valueOf(Double.parseDouble(result) - x);


} else if (lastCommand.equals("*")) {


result = String.valueOf(Double.parseDouble(result) * x);


} else if (lastCommand.equals("/")) {


result = String.valueOf(Double.parseDouble(result) / x);


}


resultField.setText(result);


}


public static void main(String[] args) {


new Calculator();


}


}

以上代码实现了加、减、乘、除等基本功能，同时支持小数的计算。你可以复制上面的代码到IDE中进行编译和运行。

  
  

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