diff --git a/codes/dart/chapter_array_and_linkedlist/array.dart b/codes/dart/chapter_array_and_linkedlist/array.dart
index 2e4fc4b006..ffd835d45b 100644
--- a/codes/dart/chapter_array_and_linkedlist/array.dart
+++ b/codes/dart/chapter_array_and_linkedlist/array.dart
@@ -29,14 +29,14 @@ List<int> extend(List<int> nums, int enlarge) {
   return res;
 }
 
-/* 在数组的索引 index 处插入元素 num */
-void insert(List<int> nums, int num, int index) {
+/* 在数组的索引 index 处插入元素 _num */
+void insert(List<int> nums, int _num, int index) {
   // 把索引 index 以及之后的所有元素向后移动一位
   for (var i = nums.length - 1; i > index; i--) {
     nums[i] = nums[i - 1];
   }
-  // 将 num 赋给 index 处元素
-  nums[index] = num;
+  // 将 _num 赋给 index 处元素
+  nums[index] = _num;
 }
 
 /* 删除索引 index 处元素 */
@@ -55,12 +55,12 @@ void traverse(List<int> nums) {
     count += nums[i];
   }
   // 直接遍历数组元素
-  for (int num in nums) {
-    count += num;
+  for (int _num in nums) {
+    count += _num;
   }
   // 通过 forEach 方法遍历数组
-  nums.forEach((num) {
-    count += num;
+  nums.forEach((_num) {
+    count += _num;
   });
 }
 
diff --git a/codes/dart/chapter_array_and_linkedlist/list.dart b/codes/dart/chapter_array_and_linkedlist/list.dart
index 784cf37f6d..050260a6ff 100644
--- a/codes/dart/chapter_array_and_linkedlist/list.dart
+++ b/codes/dart/chapter_array_and_linkedlist/list.dart
@@ -13,8 +13,8 @@ void main() {
   print('列表 nums = $nums');
 
   /* 访问元素 */
-  int num = nums[1];
-  print('访问索引 1 处的元素，得到 num = $num');
+  int _num = nums[1];
+  print('访问索引 1 处的元素，得到 _num = $_num');
 
   /* 更新元素 */
   nums[1] = 0;
diff --git a/codes/dart/chapter_array_and_linkedlist/my_list.dart b/codes/dart/chapter_array_and_linkedlist/my_list.dart
index 374aee00ed..4d54309a8c 100644
--- a/codes/dart/chapter_array_and_linkedlist/my_list.dart
+++ b/codes/dart/chapter_array_and_linkedlist/my_list.dart
@@ -29,22 +29,22 @@ class MyList {
   }
 
   /* 更新元素 */
-  void set(int index, int num) {
+  void set(int index, int _num) {
     if (index >= _size) throw RangeError('索引越界');
-    _arr[index] = num;
+    _arr[index] = _num;
   }
 
   /* 尾部添加元素 */
-  void add(int num) {
+  void add(int _num) {
     // 元素数量超出容量时，触发扩容机制
     if (_size == _capacity) extendCapacity();
-    _arr[_size] = num;
+    _arr[_size] = _num;
     // 更新元素数量
     _size++;
   }
 
   /* 中间插入元素 */
-  void insert(int index, int num) {
+  void insert(int index, int _num) {
     if (index >= _size) throw RangeError('索引越界');
     // 元素数量超出容量时，触发扩容机制
     if (_size == _capacity) extendCapacity();
@@ -52,7 +52,7 @@ class MyList {
     for (var j = _size - 1; j >= index; j--) {
       _arr[j + 1] = _arr[j];
     }
-    _arr[index] = num;
+    _arr[index] = _num;
     // 更新元素数量
     _size++;
   }
@@ -60,7 +60,7 @@ class MyList {
   /* 删除元素 */
   int remove(int index) {
     if (index >= _size) throw RangeError('索引越界');
-    int num = _arr[index];
+    int _num = _arr[index];
     // 将索引 index 之后的元素都向前移动一位
     for (var j = index; j < _size - 1; j++) {
       _arr[j] = _arr[j + 1];
@@ -68,7 +68,7 @@ class MyList {
     // 更新元素数量
     _size--;
     // 返回被删除元素
-    return num;
+    return _num;
   }
 
   /* 列表扩容 */
@@ -115,8 +115,8 @@ void main() {
   print('删除索引 3 处的元素，得到 nums = ${nums.toArray()}');
 
   /* 访问元素 */
-  int num = nums.get(1);
-  print('访问索引 1 处的元素，得到 num = $num');
+  int _num = nums.get(1);
+  print('访问索引 1 处的元素，得到 _num = $_num');
 
   /* 更新元素 */
   nums.set(1, 0);
diff --git a/codes/dart/chapter_computational_complexity/time_complexity.dart b/codes/dart/chapter_computational_complexity/time_complexity.dart
index 2e6c62c495..18b17c6f97 100644
--- a/codes/dart/chapter_computational_complexity/time_complexity.dart
+++ b/codes/dart/chapter_computational_complexity/time_complexity.dart
@@ -29,7 +29,7 @@ int linear(int n) {
 int arrayTraversal(List<int> nums) {
   int count = 0;
   // 循环次数与数组长度成正比
-  for (var num in nums) {
+  for (var _num in nums) {
     count++;
   }
   return count;
diff --git a/codes/dart/chapter_hashing/built_in_hash.dart b/codes/dart/chapter_hashing/built_in_hash.dart
index 70fba328e6..4926e2812b 100644
--- a/codes/dart/chapter_hashing/built_in_hash.dart
+++ b/codes/dart/chapter_hashing/built_in_hash.dart
@@ -8,9 +8,9 @@ import '../chapter_stack_and_queue/linkedlist_deque.dart';
 
 /* Driver Code */
 void main() {
-  int num = 3;
-  int hashNum = num.hashCode;
-  print("整数 $num 的哈希值为 $hashNum");
+  int _num = 3;
+  int hashNum = _num.hashCode;
+  print("整数 $_num 的哈希值为 $hashNum");
 
   bool bol = true;
   int hashBol = bol.hashCode;
diff --git a/codes/dart/chapter_sorting/bucket_sort.dart b/codes/dart/chapter_sorting/bucket_sort.dart
index cf9f98b878..284c6ef119 100644
--- a/codes/dart/chapter_sorting/bucket_sort.dart
+++ b/codes/dart/chapter_sorting/bucket_sort.dart
@@ -11,11 +11,11 @@ void bucketSort(List<double> nums) {
   List<List<double>> buckets = List.generate(k, (index) => []);
 
   // 1. 将数组元素分配到各个桶中
-  for (double num in nums) {
-    // 输入数据范围 [0, 1)，使用 num * k 映射到索引范围 [0, k-1]
-    int i = (num * k).toInt();
-    // 将 num 添加进桶 bucket_idx
-    buckets[i].add(num);
+  for (double _num in nums) {
+    // 输入数据范围 [0, 1)，使用 _num * k 映射到索引范围 [0, k-1]
+    int i = (_num * k).toInt();
+    // 将 _num 添加进桶 bucket_idx
+    buckets[i].add(_num);
   }
   // 2. 对各个桶执行排序
   for (List<double> bucket in buckets) {
@@ -24,8 +24,8 @@ void bucketSort(List<double> nums) {
   // 3. 遍历桶合并结果
   int i = 0;
   for (List<double> bucket in buckets) {
-    for (double num in bucket) {
-      nums[i++] = num;
+    for (double _num in bucket) {
+      nums[i++] = _num;
     }
   }
 }
diff --git a/codes/dart/chapter_sorting/counting_sort.dart b/codes/dart/chapter_sorting/counting_sort.dart
index d7634ef834..92cf9b5467 100644
--- a/codes/dart/chapter_sorting/counting_sort.dart
+++ b/codes/dart/chapter_sorting/counting_sort.dart
@@ -10,20 +10,20 @@ import 'dart:math';
 void countingSortNaive(List<int> nums) {
   // 1. 统计数组最大元素 m
   int m = 0;
-  for (int num in nums) {
-    m = max(m, num);
+  for (int _num in nums) {
+    m = max(m, _num);
   }
   // 2. 统计各数字的出现次数
-  // counter[num] 代表 num 的出现次数
+  // counter[_num] 代表 _num 的出现次数
   List<int> counter = List.filled(m + 1, 0);
-  for (int num in nums) {
-    counter[num]++;
+  for (int _num in nums) {
+    counter[_num]++;
   }
   // 3. 遍历 counter ，将各元素填入原数组 nums
   int i = 0;
-  for (int num = 0; num < m + 1; num++) {
-    for (int j = 0; j < counter[num]; j++, i++) {
-      nums[i] = num;
+  for (int _num = 0; _num < m + 1; _num++) {
+    for (int j = 0; j < counter[_num]; j++, i++) {
+      nums[i] = _num;
     }
   }
 }
@@ -33,17 +33,17 @@ void countingSortNaive(List<int> nums) {
 void countingSort(List<int> nums) {
   // 1. 统计数组最大元素 m
   int m = 0;
-  for (int num in nums) {
-    m = max(m, num);
+  for (int _num in nums) {
+    m = max(m, _num);
   }
   // 2. 统计各数字的出现次数
-  // counter[num] 代表 num 的出现次数
+  // counter[_num] 代表 _num 的出现次数
   List<int> counter = List.filled(m + 1, 0);
-  for (int num in nums) {
-    counter[num]++;
+  for (int _num in nums) {
+    counter[_num]++;
   }
   // 3. 求 counter 的前缀和，将“出现次数”转换为“尾索引”
-  // 即 counter[num]-1 是 num 在 res 中最后一次出现的索引
+  // 即 counter[_num]-1 是 _num 在 res 中最后一次出现的索引
   for (int i = 0; i < m; i++) {
     counter[i + 1] += counter[i];
   }
@@ -52,9 +52,9 @@ void countingSort(List<int> nums) {
   int n = nums.length;
   List<int> res = List.filled(n, 0);
   for (int i = n - 1; i >= 0; i--) {
-    int num = nums[i];
-    res[counter[num] - 1] = num; // 将 num 放置到对应索引处
-    counter[num]--; // 令前缀和自减 1 ，得到下次放置 num 的索引
+    int _num = nums[i];
+    res[counter[_num] - 1] = _num; // 将 _num 放置到对应索引处
+    counter[_num]--; // 令前缀和自减 1 ，得到下次放置 _num 的索引
   }
   // 使用结果数组 res 覆盖原数组 nums
   nums.setAll(0, res);
diff --git a/codes/dart/chapter_sorting/radix_sort.dart b/codes/dart/chapter_sorting/radix_sort.dart
index 095dc90f94..3f19d15e18 100644
--- a/codes/dart/chapter_sorting/radix_sort.dart
+++ b/codes/dart/chapter_sorting/radix_sort.dart
@@ -4,10 +4,10 @@
  * Author: what-is-me (whatisme@outlook.jp)
  */
 
-/* 获取元素 num 的第 k 位，其中 exp = 10^(k-1) */
-int digit(int num, int exp) {
+/* 获取元素 _num 的第 k 位，其中 exp = 10^(k-1) */
+int digit(int _num, int exp) {
   // 传入 exp 而非 k 可以避免在此重复执行昂贵的次方计算
-  return (num ~/ exp) % 10;
+  return (_num ~/ exp) % 10;
 }
 
 /* 计数排序（根据 nums 第 k 位排序） */
@@ -41,7 +41,7 @@ void radixSort(List<int> nums) {
   // 获取数组的最大元素，用于判断最大位数
   // dart 中 int 的长度是 64 位的
   int m = -1 << 63;
-  for (int num in nums) if (num > m) m = num;
+  for (int _num in nums) if (_num > m) m = _num;
   // 按照从低位到高位的顺序遍历
   for (int exp = 1; exp <= m; exp *= 10)
     // 对数组元素的第 k 位执行计数排序
diff --git a/codes/dart/chapter_stack_and_queue/array_deque.dart b/codes/dart/chapter_stack_and_queue/array_deque.dart
index 722867b008..34eba9c8d4 100644
--- a/codes/dart/chapter_stack_and_queue/array_deque.dart
+++ b/codes/dart/chapter_stack_and_queue/array_deque.dart
@@ -40,44 +40,44 @@ class ArrayDeque {
   }
 
   /* 队首入队 */
-  void pushFirst(int num) {
+  void pushFirst(int _num) {
     if (_queSize == capacity()) {
       throw Exception("双向队列已满");
     }
     // 队首指针向左移动一位
     // 通过取余操作，实现 _front 越过数组头部后回到尾部
     _front = index(_front - 1);
-    // 将 num 添加至队首
-    _nums[_front] = num;
+    // 将 _num 添加至队首
+    _nums[_front] = _num;
     _queSize++;
   }
 
   /* 队尾入队 */
-  void pushLast(int num) {
+  void pushLast(int _num) {
     if (_queSize == capacity()) {
       throw Exception("双向队列已满");
     }
     // 计算尾指针，指向队尾索引 + 1
     int rear = index(_front + _queSize);
-    // 将 num 添加至队尾
-    _nums[rear] = num;
+    // 将 _num 添加至队尾
+    _nums[rear] = _num;
     _queSize++;
   }
 
   /* 队首出队 */
   int popFirst() {
-    int num = peekFirst();
+    int _num = peekFirst();
     // 队首指针向右移动一位
     _front = index(_front + 1);
     _queSize--;
-    return num;
+    return _num;
   }
 
   /* 队尾出队 */
   int popLast() {
-    int num = peekLast();
+    int _num = peekLast();
     _queSize--;
-    return num;
+    return _num;
   }
 
   /* 访问队首元素 */
diff --git a/codes/dart/chapter_stack_and_queue/array_queue.dart b/codes/dart/chapter_stack_and_queue/array_queue.dart
index 369af4c54e..8c25e75e81 100644
--- a/codes/dart/chapter_stack_and_queue/array_queue.dart
+++ b/codes/dart/chapter_stack_and_queue/array_queue.dart
@@ -31,25 +31,25 @@ class ArrayQueue {
   }
 
   /* 入队 */
-  void push(int num) {
+  void push(int _num) {
     if (_queSize == capaCity()) {
       throw Exception("队列已满");
     }
     // 计算尾指针，指向队尾索引 + 1
     // 通过取余操作，实现 rear 越过数组尾部后回到头部
     int rear = (_front + _queSize) % capaCity();
-    // 将 num 添加至队尾
-    _nums[rear] = num;
+    // 将 _num 添加至队尾
+    _nums[rear] = _num;
     _queSize++;
   }
 
   /* 出队 */
   int pop() {
-    int num = peek();
+    int _num = peek();
     // 队首指针向后移动一位，若越过尾部则返回到数组头部
     _front = (_front + 1) % capaCity();
     _queSize--;
-    return num;
+    return _num;
   }
 
   /* 访问队首元素 */
diff --git a/codes/dart/chapter_stack_and_queue/array_stack.dart b/codes/dart/chapter_stack_and_queue/array_stack.dart
index 485d2359eb..bd6918f78e 100644
--- a/codes/dart/chapter_stack_and_queue/array_stack.dart
+++ b/codes/dart/chapter_stack_and_queue/array_stack.dart
@@ -22,8 +22,8 @@ class ArrayStack {
   }
 
   /* 入栈 */
-  void push(int num) {
-    _stack.add(num);
+  void push(int _num) {
+    _stack.add(_num);
   }
 
   /* 出栈 */
diff --git a/codes/dart/chapter_stack_and_queue/linkedlist_deque.dart b/codes/dart/chapter_stack_and_queue/linkedlist_deque.dart
index 91df529c09..08d0dd8071 100644
--- a/codes/dart/chapter_stack_and_queue/linkedlist_deque.dart
+++ b/codes/dart/chapter_stack_and_queue/linkedlist_deque.dart
@@ -35,8 +35,8 @@ class LinkedListDeque {
   }
 
   /* 入队操作 */
-  void push(int num, bool isFront) {
-    final ListNode node = ListNode(num);
+  void push(int _num, bool isFront) {
+    final ListNode node = ListNode(_num);
     if (isEmpty()) {
       // 若链表为空，则令 _front 和 _rear 都指向 node
       _front = _rear = node;
@@ -57,13 +57,13 @@ class LinkedListDeque {
   }
 
   /* 队首入队 */
-  void pushFirst(int num) {
-    push(num, true);
+  void pushFirst(int _num) {
+    push(_num, true);
   }
 
   /* 队尾入队 */
-  void pushLast(int num) {
-    push(num, false);
+  void pushLast(int _num) {
+    push(_num, false);
   }
 
   /* 出队操作 */
diff --git a/codes/dart/chapter_stack_and_queue/linkedlist_queue.dart b/codes/dart/chapter_stack_and_queue/linkedlist_queue.dart
index cdd801ab76..567a640437 100644
--- a/codes/dart/chapter_stack_and_queue/linkedlist_queue.dart
+++ b/codes/dart/chapter_stack_and_queue/linkedlist_queue.dart
@@ -28,9 +28,9 @@ class LinkedListQueue {
   }
 
   /* 入队 */
-  void push(int num) {
-    // 尾节点后添加 num
-    final node = ListNode(num);
+  void push(int _num) {
+    // 尾节点后添加 _num
+    final node = ListNode(_num);
     // 如果队列为空，则令头、尾节点都指向该节点
     if (_front == null) {
       _front = node;
@@ -45,11 +45,11 @@ class LinkedListQueue {
 
   /* 出队 */
   int pop() {
-    final int num = peek();
+    final int _num = peek();
     // 删除头节点
     _front = _front!.next;
     _queSize--;
-    return num;
+    return _num;
   }
 
   /* 访问队首元素 */
diff --git a/codes/dart/chapter_stack_and_queue/linkedlist_stack.dart b/codes/dart/chapter_stack_and_queue/linkedlist_stack.dart
index 44164db260..1efaa54636 100644
--- a/codes/dart/chapter_stack_and_queue/linkedlist_stack.dart
+++ b/codes/dart/chapter_stack_and_queue/linkedlist_stack.dart
@@ -26,8 +26,8 @@ class LinkedListStack {
   }
 
   /* 入栈 */
-  void push(int num) {
-    final ListNode node = ListNode(num);
+  void push(int _num) {
+    final ListNode node = ListNode(_num);
     node.next = _stackPeek;
     _stackPeek = node;
     _stkSize++;
@@ -35,10 +35,10 @@ class LinkedListStack {
 
   /* 出栈 */
   int pop() {
-    final int num = peek();
+    final int _num = peek();
     _stackPeek = _stackPeek!.next;
     _stkSize--;
-    return num;
+    return _num;
   }
 
   /* 访问栈顶元素 */
diff --git a/codes/dart/chapter_tree/binary_search_tree.dart b/codes/dart/chapter_tree/binary_search_tree.dart
index 901466584b..4deaef3d42 100644
--- a/codes/dart/chapter_tree/binary_search_tree.dart
+++ b/codes/dart/chapter_tree/binary_search_tree.dart
@@ -23,15 +23,15 @@ class BinarySearchTree {
   }
 
   /* 查找节点 */
-  TreeNode? search(int num) {
+  TreeNode? search(int _num) {
     TreeNode? cur = _root;
     // 循环查找，越过叶节点后跳出
     while (cur != null) {
       // 目标节点在 cur 的右子树中
-      if (cur.val < num)
+      if (cur.val < _num)
         cur = cur.right;
       // 目标节点在 cur 的左子树中
-      else if (cur.val > num)
+      else if (cur.val > _num)
         cur = cur.left;
       // 找到目标节点，跳出循环
       else
@@ -42,10 +42,10 @@ class BinarySearchTree {
   }
 
   /* 插入节点 */
-  void insert(int num) {
+  void insert(int _num) {
     // 若树为空，则初始化根节点
     if (_root == null) {
-      _root = TreeNode(num);
+      _root = TreeNode(_num);
       return;
     }
     TreeNode? cur = _root;
@@ -53,25 +53,25 @@ class BinarySearchTree {
     // 循环查找，越过叶节点后跳出
     while (cur != null) {
       // 找到重复节点，直接返回
-      if (cur.val == num) return;
+      if (cur.val == _num) return;
       pre = cur;
       // 插入位置在 cur 的右子树中
-      if (cur.val < num)
+      if (cur.val < _num)
         cur = cur.right;
       // 插入位置在 cur 的左子树中
       else
         cur = cur.left;
     }
     // 插入节点
-    TreeNode? node = TreeNode(num);
-    if (pre!.val < num)
+    TreeNode? node = TreeNode(_num);
+    if (pre!.val < _num)
       pre.right = node;
     else
       pre.left = node;
   }
 
   /* 删除节点 */
-  void remove(int num) {
+  void remove(int _num) {
     // 若树为空，直接提前返回
     if (_root == null) return;
     TreeNode? cur = _root;
@@ -79,10 +79,10 @@ class BinarySearchTree {
     // 循环查找，越过叶节点后跳出
     while (cur != null) {
       // 找到待删除节点，跳出循环
-      if (cur.val == num) break;
+      if (cur.val == _num) break;
       pre = cur;
       // 待删除节点在 cur 的右子树中
-      if (cur.val < num)
+      if (cur.val < _num)
         cur = cur.right;
       // 待删除节点在 cur 的左子树中
       else
@@ -125,8 +125,8 @@ void main() {
   BinarySearchTree bst = BinarySearchTree();
   // 请注意，不同的插入顺序会生成不同的二叉树，该序列可以生成一个完美二叉树
   List<int> nums = [8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15];
-  for (int num in nums) {
-    bst.insert(num);
+  for (int _num in nums) {
+    bst.insert(_num);
   }
   print("\n初始化的二叉树为\n");
   printTree(bst.getRoot());