second

test/Calculator.java

@@ -0,0 +1,112 @@
+package java6226.lesson05;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class Calculator extends JFrame {
+    private JTextField display;
+    private double result = 0;
+    private String operator = "";
+    private boolean calculating = true;
+
+    public Calculator() {
+        setTitle("Simple Calculator");
+        setSize(250, 350);
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setLayout(new BorderLayout());
+
+        display = new JTextField("0");
+        display.setEditable(false);
+        display.setHorizontalAlignment(JTextField.RIGHT);
+        add(display, BorderLayout.NORTH);
+
+        JPanel buttonPanel = new JPanel();
+        buttonPanel.setLayout(new GridLayout(4, 4, 5, 5)); // 4行4列的按钮布局
+
+        String[] buttonLabels = {
+                "7", "8", "9", "/",
+                "4", "5", "6", "*",
+                "1", "2", "3", "-",
+                "C", "0", "=", "+"
+        };
+
+        for (String label : buttonLabels) {
+            JButton button = new JButton(label);
+            button.setFont(new Font("Arial", Font.BOLD, 18));
+            button.setPreferredSize(new Dimension(50, 40));
+            button.addActionListener(new ButtonClickListener());
+            buttonPanel.add(button);
+        }
+
+        add(buttonPanel, BorderLayout.CENTER);
+        setVisible(true);
+    }
+
+    private class ButtonClickListener implements ActionListener {
+        public void actionPerformed(ActionEvent e) {
+            String command = e.getActionCommand();
+            if (calculating) {
+                if (command.equals("C")) {
+                    display.setText("0");
+                    operator = "";
+                    result = 0;
+                    calculating = true;
+                } else if (command.equals("+") || command.equals("-") || command.equals("*") || command.equals("/")) {
+                    operator = command;
+                    calculating = false;
+                    display.setText("");
+                } else if (command.equals("=")) {
+                    calculate(Double.parseDouble(display.getText()));
+                } else {
+                    display.setText(display.getText() + command);
+                }
+            } else {
+                if (command.equals("C")) {
+                    display.setText("0");
+                    operator = "";
+                    result = 0;
+                    calculating = true;
+                } else if (command.equals("=")) {
+                    calculate(Double.parseDouble(display.getText()));
+                } else {
+                    display.setText(display.getText() + command);
+                }
+            }
+        }
+
+        private void calculate(double num) {
+            switch (operator) {
+                case "+":
+                    result += num;
+                    break;
+                case "-":
+                    result -= num;
+                    break;
+                case "*":
+                    result *= num;
+                    break;
+                case "/":
+                    if (num != 0) {
+                        result /= num;
+                    } else {
+                        display.setText("Error");
+                        return;
+                    }
+                    break;
+            }
+            display.setText("" + result);
+            operator = "";
+            calculating = true;
+        }
+    }
+
+    public static void main(String[] args) {
+        SwingUtilities.invokeLater(new Runnable() {
+            public void run() {
+                new Calculator();
+            }
+        });
+    }
+}