v1

calculator.java

@@ -15,7 +15,6 @@ public class calculator extends JFrame implements ActionListener {
         setDefaultCloseOperation(EXIT_ON_CLOSE);
         setLayout(new BorderLayout());
 
-        // 增加结果显示区域的高度
         display = new JTextField("0");
         display.setEditable(false);
         display.setHorizontalAlignment(JTextField.RIGHT);
@@ -24,14 +23,14 @@ public class calculator extends JFrame implements ActionListener {
         add(display, BorderLayout.NORTH);
 
         JPanel panel = new JPanel();
-        panel.setLayout(new GridLayout(5, 4)); // 增加一行用于放置清除按钮
+        panel.setLayout(new GridLayout(5, 4));
 
         String[] buttons = {
                 "7", "8", "9", "/",
                 "4", "5", "6", "*",
                 "1", "2", "3", "-",
                 "0", ".", "=", "+",
-                "C" // 清除按钮
+                "C", "%" // 添加取余按钮
         };
 
         for (String label : buttons) {
@@ -42,7 +41,7 @@ public class calculator extends JFrame implements ActionListener {
         }
 
         add(panel, BorderLayout.CENTER);
-        setLocationRelativeTo(null); // 居中显示
+        setLocationRelativeTo(null);
     }
 
     @Override
@@ -56,15 +55,14 @@ public class calculator extends JFrame implements ActionListener {
             } else {
                 display.setText(display.getText() + command);
             }
-        } else if ("+-*/%".indexOf(command) >= 0) {
+        } else if ("+-*/%".indexOf(command) >= 0) { // 添加 % 运算符
             equation = display.getText() + command;
             display.setText("0");
             newNumber = true;
         } else if (command.equals("=")) {
             try {
                 equation += display.getText();
-                double result = eval(equation);
-                // 检查结果是否为整数
+                double result = new ExpressionEvaluator(equation).evaluate();
                 if (result == (long) result) {
                     display.setText(String.valueOf((long) result));
                 } else {
@@ -81,75 +79,79 @@ public class calculator extends JFrame implements ActionListener {
         }
     }
 
-    private double eval(final String str) {
-        return new Object() {
-            int pos = -1, ch;
+    public static void main(String[] args) {
+        SwingUtilities.invokeLater(() -> {
+            calculator calc = new calculator();
+            calc.setVisible(true);
+        });
+    }
+}
 
-            void nextChar() {
-                ch = (++pos < str.length()) ? str.charAt(pos) : -1;
-            }
+class ExpressionEvaluator {
+    private int pos = -1;
+    private int ch;
+    private final String str;
 
-            boolean eat(int charToEat) {
-                while (ch == ' ') nextChar();
-                if (ch == charToEat) {
-                    nextChar();
-                    return true;
-                }
-                return false;
-            }
+    public ExpressionEvaluator(String str) {
+        this.str = str;
+    }
 
-            double parse() {
-                nextChar();
-                double x = parseExpression();
-                if (pos < str.length()) throw new RuntimeException("Unexpected: " + (char)ch);
-                return x;
-            }
+    private void nextChar() {
+        ch = (++pos < str.length()) ? str.charAt(pos) : -1;
+    }
 
-            double parseExpression() {
-                double x = parseTerm();
-                for (;;) {
-                    if      (eat('+')) x += parseTerm(); // addition
-                    else if (eat('-')) x -= parseTerm(); // subtraction
-                    else return x;
-                }
-            }
+    private boolean eat(int charToEat) {
+        while (ch == ' ') nextChar();
+        if (ch == charToEat) {
+            nextChar();
+            return true;
+        }
+        return false;
+    }
 
-            double parseTerm() {
-                double x = parseFactor();
-                for (;;) {
-                    if      (eat('*')) x *= parseFactor(); // multiplication
-                    else if (eat('/')) x /= parseFactor(); // division
-                    else return x;
-                }
-            }
+    public double evaluate() {
+        nextChar();
+        double x = parseExpression();
+        if (pos < str.length()) throw new RuntimeException("Unexpected: " + (char)ch);
+        return x;
+    }
 
-            double parseFactor() {
-                if (eat('+')) return parseFactor(); // unary plus
-                if (eat('-')) return -parseFactor(); // unary minus
-
-                double x;
-                int startPos = this.pos;
-                if (eat('(')) { // parentheses
-                    x = parseExpression();
-                    eat(')');
-                } else if ((ch >= '0' && ch <= '9') || ch == '.') { // numbers
-                    while ((ch >= '0' && ch <= '9') || ch == '.') nextChar();
-                    x = Double.parseDouble(str.substring(startPos, this.pos));
-                } else {
-                    throw new RuntimeException("Unexpected: " + (char)ch);
-                }
+    private double parseExpression() {
+        double x = parseTerm();
+        for (;;) {
+            if (eat('+')) x += parseTerm(); // addition
+            else if (eat('-')) x -= parseTerm(); // subtraction
+            else return x;
+        }
+    }
 
-                if (eat('^')) x = Math.pow(x, parseFactor()); // exponentiation
-                return x;
-            }
-        }.parse();
+    private double parseTerm() {
+        double x = parseFactor();
+        for (;;) {
+            if (eat('*')) x *= parseFactor(); // multiplication
+            else if (eat('/')) x /= parseFactor(); // division
+            else if (eat('%')) x %= parseFactor(); // modulus
+            else return x;
+        }
     }
 
-    public static void main(String[] args) {
-        SwingUtilities.invokeLater(() -> {
-            calculator calc = new calculator();
-            calc.setVisible(true);
-        });
+    private double parseFactor() {
+        if (eat('+')) return parseFactor(); // unary plus
+        if (eat('-')) return -parseFactor(); // unary minus
+
+        double x;
+        int startPos = this.pos;
+        if (eat('(')) { // parentheses
+            x = parseExpression();
+            eat(')');
+        } else if ((ch >= '0' && ch <= '9') || ch == '.') { // numbers
+            while ((ch >= '0' && ch <= '9') || ch == '.') nextChar();
+            x = Double.parseDouble(str.substring(startPos, this.pos));
+        } else {
+            throw new RuntimeException("Unexpected: " + (char)ch);
+        }
+
+        if (eat('^')) x = Math.pow(x, parseFactor()); // exponentiation
+        return x;
     }
 }
-