16号第一次修改

Calculator.java

@@ -2,12 +2,14 @@ import javax.swing.*;
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
-import javax.script.ScriptEngineManager;
 import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
 import javax.script.ScriptException;
+
 public class Calculator extends JFrame implements ActionListener {
     private JTextField display;
     private StringBuilder input;
+
     public Calculator() {
         input = new StringBuilder();
         display = new JTextField();
@@ -16,13 +18,14 @@ public class Calculator extends JFrame implements ActionListener {
         display.setHorizontalAlignment(JTextField.RIGHT);
         display.setBackground(Color.LIGHT_GRAY);
         JPanel panel = new JPanel();
-        panel.setLayout(new GridLayout(4, 4, 10, 10));
+        panel.setLayout(new GridLayout(5, 4, 10, 10)); // Increase number of rows
         panel.setBackground(Color.GRAY);
         String[] buttons = {
                 "7", "8", "9", "/",
                 "4", "5", "6", "*",
                 "1", "2", "3", "-",
-                "C", "0", "=", "+"
+                "C", "0", ".", "+", // Add decimal point
+                "<-", "=", "" // Add delete button
         };
         for (String text : buttons) {
             JButton button = new JButton(text);
@@ -38,34 +41,9 @@ public class Calculator extends JFrame implements ActionListener {
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         setLocationRelativeTo(null);
     }
+
+    @Override
     public void actionPerformed(ActionEvent e) {
-        String command = e.getActionCommand();
 
-        if (command.charAt(0) == 'C') {
-            input.setLength(0);
-            display.setText("");
-        } else if (command.charAt(0) == '=') {
-            try {
-                double result = evaluate(input.toString());
-                display.setText(String.valueOf(result));
-                input.setLength(0);
-            } catch (ScriptException ex) {
-                display.setText("Error");
-                input.setLength(0);
-            }
-        } else {
-            input.append(command);
-            display.setText(input.toString());
-        }
-    }
-    private double evaluate(String expression) throws ScriptException {
-        ScriptEngine engine = new ScriptEngineManager().getEngineByName("JavaScript");
-        return ((Number) engine.eval(expression)).doubleValue();
-    }
-    public static void main(String[] args) {
-        SwingUtilities.invokeLater(() -> {
-            Calculator calculator = new Calculator();
-            calculator.setVisible(true);
-        });
     }
-}
+}