《Java程序设计》第一次作业：简单的JAVA源代码之计算器

这周的作业就是这个简单的JAVA源代码计算器，我通过查看相关的JAVA书籍和网上阅读资料分析，在重复的运行，查看，检查过程中，修改那些自己打入错误失误的代码，

自己想明白这行串代码的意思是什么，在这个过程中有些代码通过网上查询来得到的，比如说实现计算器的运算，这个过程就要通过网上查询相关代码来得到这个的资料

，通过自己的学习如何去理解的。这个过程对于初学的我的确不容易，下面有几行代码中，我发现有些键位可以不需要，便不显示出来了，但是这要检查哪些代码需要不要，需要修改，所以这个过程就比较繁琐了，所以在不知道怎么删除时，我的处理方法就是先不要那个键位，因为它并不影响整个计算器的运算，比如在代码第33行中的“00”键位，我觉得就不需要，只是方便我们的使用，但是这个就复杂了计算器的模样，所以我本人是喜欢越简单约好的东西，不需要这个繁琐的模样了。运行结果在代码后面有显示，希望老师理解！

</pre><pre name="code" class="java">import javax.swing.*;import java.awt.*;import java.awt.event.*;class Result extends JPanel {JTextField text = new JTextField("0");Result() {text.setHorizontalAlignment(SwingConstants.RIGHT);text.enable(false);setLayout(new BorderLayout());add(text, BorderLayout.CENTER);}}class Number_Key extends JPanel {JButton zero = new JButton("0");JButton one = new JButton("1");JButton two = new JButton("2");JButton three = new JButton("3");JButton four = new JButton("4");JButton five = new JButton("5");JButton six = new JButton("6");JButton seven = new JButton("7");JButton eight = new JButton("8");JButton nine = new JButton("9");JButton plus = new JButton("+");JButton sub = new JButton("-");JButton mul = new JButton("*");JButton div = new JButton("/");JButton equal = new JButton("=");JButton c = new JButton("c");JButton point = new JButton(".");JButton tzero = new JButton("00");Number_Key() {setLayout(new GridLayout(5, 4, 12, 12));add(seven);add(eight);add(nine);add(div);add(four);add(five);add(six);add(mul);add(one);add(two);add(three);add(sub);add(c);add(zero);add(point);add(plus);add(equal);}}public class Calculator extends JFrame implements ActionListener {Result result = new Result();Number_Key number_key = new Number_Key();boolean com = false;int i = 0;String sum = "";double total = 0;int symbol = 0;Calculator() {super("威威的计算机");setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);JPanel pane = new JPanel();pane.setLayout(new BorderLayout());pane.add(result, BorderLayout.NORTH);pane.add(number_key, BorderLayout.SOUTH);number_key.one.addActionListener(this);number_key.two.addActionListener(this);number_key.three.addActionListener(this);number_key.four.addActionListener(this);number_key.five.addActionListener(this);number_key.six.addActionListener(this);number_key.seven.addActionListener(this);number_key.eight.addActionListener(this);number_key.nine.addActionListener(this);number_key.zero.addActionListener(this);number_key.c.addActionListener(this);number_key.plus.addActionListener(this);number_key.equal.addActionListener(this);number_key.sub.addActionListener(this);number_key.mul.addActionListener(this);number_key.div.addActionListener(this);number_key.point.addActionListener(this);setContentPane(pane);pack();}public void actionPerformed(ActionEvent e) {if (e.getSource() == number_key.one) {if (com || i == 0) {result.text.setText("1");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "1");}} else if (e.getSource() == number_key.two) {if (com || i == 0) {result.text.setText("2");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "2");}} else if (e.getSource() == number_key.three) {if (com || i == 0) {result.text.setText("3");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "3");}} else if (e.getSource() == number_key.four) {if (com || i == 0) {result.text.setText("4");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "4");}} else if (e.getSource() == number_key.five) {if (com || i == 0) {result.text.setText("5");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "5");}} else if (e.getSource() == number_key.six) {if (com || i == 0) {result.text.setText("6");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "6");}} else if (e.getSource() == number_key.seven) {if (com || i == 0) {result.text.setText("7");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "7");}} else if (e.getSource() == number_key.eight) {if (com || i == 0) {result.text.setText("8");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "8");}} else if (e.getSource() == number_key.nine) {if (com || i == 0) {result.text.setText("9");com = false;i = 1;} else {sum = result.text.getText();result.text.setText(sum + "9");}}else if (e.getSource() == number_key.zero) {if (com || i == 0) {result.text.setText("0");com = false;i = 1;} else {sum = result.text.getText();if (Float.parseFloat(sum) > 0 || Float.parseFloat(sum) < 0) {result.text.setText(sum + "0");} else {if (sum.trim().indexOf(".") == -1) {result.text.setText(sum);} else {result.text.setText(sum + "0");}}}} else if (e.getSource() == number_key.c) {result.text.setText("0");i = 0;com = true;} else if (e.getSource() == number_key.tzero) {if (com || i == 0) {result.text.setText("0");com = false;i = 1;} else {sum = result.text.getText();if (Float.parseFloat(sum) > 0 || Float.parseFloat(sum) < 0) {result.text.setText(sum + "00");} else {if (sum.trim().indexOf(".") == -1) {result.text.setText(sum);} else {result.text.setText(sum + "00");}}}}else if (e.getSource() == number_key.point) {if (com || i == 0) {result.text.setText("0.");com = false;i = 1;} else {sum = result.text.getText();if (sum.trim().indexOf(".") == -1) {result.text.setText(sum + ".");} else {result.text.setText(sum);}}}else if (e.getSource() == number_key.plus) {com = true;i = 0;total = Double.parseDouble(result.text.getText());symbol = 1;}else if (e.getSource() == number_key.sub) {com = true;i = 0;total = Double.parseDouble(result.text.getText());symbol = 2;}else if (e.getSource() == number_key.mul) {com = true;i = 0;total = Double.parseDouble(result.text.getText());System.out.println(total);symbol = 3;}else if (e.getSource() == number_key.div) {com = true;i = 0;total = Double.parseDouble(result.text.getText());symbol = 4;} else if (e.getSource() == number_key.equal) {switch (symbol) {case 1 :{double ad =total + Double.parseDouble(result.text.getText());result.text.setText(ad + "");i = 0;sum = "";break;}case 2 :{double ad =total - Double.parseDouble(result.text.getText());result.text.setText(String.valueOf(ad));i = 0;sum = "";break;}case 3 :{double ad =total * Double.parseDouble(result.text.getText());result.text.setText(ad + "");i = 0;sum = "";break;}case 4 :{double ad =total / Double.parseDouble(result.text.getText());result.text.setText(ad + "");i = 0;sum = "";break;}}System.out.println(com);}}public static void main(String[] args) {Calculator ww = new Calculator();ww.show();最后通过检查，修改了其实不能让计算器运行的小错误！