Java计算器源代码(已成功运行)

以下为代码：

importjavax.swing.*; importjava.awt.*; importjava.awt.event.*; public

class

Calculator

extends

JFrame

implements

ActionListener {

private booleandotExist, operated, equaled; // 帮助运算的布尔变量

private double storedNumber; // 目前的结果 private char lastOperator; // 表示上一运算符 private JTextField operation; // 结果栏

private JButton dot, plus, minus, multi, div, sqrt, equal, changePN, clear; //运算符

private JButton[] numbers; // 数字 // 构造者 public Calculator() {

setTitle(\"Calculator\"); // 初始化变量

dotExist = false; // 表示当前的数是否有小数点

operated = false; // 表示任意运算符是否被按下 equaled = false; // 表示等号是否被按下 storedNumber = 0; lastOperator = '?'; // 初始化窗口变量 operation = new JTextField(\"0\"); operation.setEditable(false); numbers = new JButton[10]; for (inti = 0; i< 10; i++) numbers[i] = new JButton(\"\" + i); dot = new JButton(\".\"); plus = new JButton(\"+\"); minus = new JButton(\"-\"); multi = new JButton(\"*\"); div = new JButton(\"/\"); sqrt = new JButton(\"√\"); equal = new JButton(\"=\"); changePN = new JButton(\"±\"); clear = new JButton(\"AC\"); // 将窗口物体放入窗口

GridBagLayout layout = new GridBagLayout(); getContentPane().setLayout(layout);

addComponent(layout, operation, 0, 0, 4, 1); addComponent(layout, numbers[1], 1, 0, 1, 1); addComponent(layout, numbers[2], 1, 1, 1, 1); addComponent(layout, numbers[3], 1, 2, 1, 1); addComponent(layout, numbers[4], 2, 0, 1, 1); addComponent(layout, numbers[5], 2, 1, 1, 1); addComponent(layout, numbers[6], 2, 2, 1, 1); addComponent(layout, numbers[7], 3, 0, 1, 1); addComponent(layout, numbers[8], 3, 1, 1, 1); addComponent(layout, numbers[9], 3, 2, 1, 1); addComponent(layout, dot, 4, 0, 1, 1); addComponent(layout, numbers[0], 4, 1, 1, 1); addComponent(layout, sqrt, 4, 2, 1, 1); addComponent(layout, plus, 1, 3, 1, 1); addComponent(layout, minus, 2, 3, 1, 1); addComponent(layout, multi, 3, 3, 1, 1); addComponent(layout, div, 4, 3, 1, 1); addComponent(layout, equal, 5, 0, 2, 1); addComponent(layout, changePN, 5, 2, 1, 1); addComponent(layout, clear, 5, 3, 1, 1); }

// 对按钮进行反应的方法

public void actionPerformed(ActionEvent e) {

JButtonbtn = (JButton)e.getSource(); if (btn == clear) {

operation.setText(\"0\"); dotExist = false; storedNumber = 0; lastOperator = '?'; }

else if (btn == equal) { operate('='); equaled = true; }

else if (btn == plus) { operate('+'); equaled = false; }

else if (btn == minus) {

operate('-'); equaled = false; }

else if (btn == multi) { operate('*'); equaled = false; }

else if (btn == div) { operate('/'); equaled = false; }

else if (btn == changePN) { operate('p'); operate('='); equaled = true; }

else if (btn == sqrt) { operate('s');

operate('='); equaled = true; } else { if (equaled) storedNumber = 0;

for (inti = 0; i< 10; i++) if (btn == numbers[i]) {

if (operation.getText().equals(\"0\")) operation.setText(\"\" + i); else if(! operated)

operation.setText(operation.getText() + i); else

{ operation.setText(\"\" + i); operated = false; } }

if (btn == dot && ! dotExist) {

operation.setText(operation.getText() + \".\"); dotExist = true; } } }

// 进行运算的方法

private void operate(char operator) {

doublecurrentNumber

Double.valueOf(operation.getText()).doubleValue(); if (lastOperator == '?') storedNumber = currentNumber; else if (lastOperator == '+') storedNumber += currentNumber; else if (lastOperator == '-') storedNumber -= currentNumber; else if (lastOperator == '*') storedNumber *= currentNumber; else if (lastOperator == '/') storedNumber /= currentNumber; else if (lastOperator == 'p') storedNumber *= -1;

=

else if (lastOperator == 's')

storedNumber = Math.sqrt(currentNumber); else if (lastOperator == '=' && equaled) storedNumber = currentNumber; operation.setText(\"\" + storedNumber); operated = true; lastOperator = operator; }

// 快捷使用GridBagLayout的方法

private void addComponent(GridBagLayout layout, Component component, int row, int col, int width, int height) {

GridBagConstraints constraints=new GridBagConstraints(); constraints.fill = GridBagConstraints.BOTH; constraints.insets = new Insets(10, 2, 10, 2); constraints.weightx = 100; constraints.weighty = 100; constraints.gridx = col; constraints.gridy = row; constraints.gridwidth = width; constraints.gridheight = height;

layout.setConstraints(component, constraints);

if (component instanceofJButton)

((JButton)component).addActionListener(this); getContentPane().add(component); }

// 主方法初始化并显示窗口

public static void main(String[] args) {

Calculator calc = new Calculator(); calc.setSize(290, 400); calc.setVisible(true); } }