陈佳媛1016提交

Calculator.java

@@ -42,8 +42,41 @@ public class Calculator extends JFrame implements ActionListener {
         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.equals("<-")) { // Delete the last character
+            if (input.length() > 0) {
+                input.setLength(input.length() - 1);
+                display.setText(input.toString());
+            }
+        } 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);
+        });
     }
 }