实现迭代器模式示例，添加任务结构体、迭代器接口及具体实现，增强代码可读性

go/iterator/main.go

@@ -0,0 +1,101 @@
+package main
+
+import "fmt"
+
+/*
+实例：
+汤宝宝有一张TODO表，记录着自己想干的事情。
+*/
+
+// 任务结构体 - 迭代器元素
+type Todo struct {
+	content string
+	done    bool
+}
+
+// 迭代器接口
+type Iterator interface {
+	First() *Todo
+	Next() *Todo
+	isDone() bool
+	CurrentItem() int
+}
+
+// 具体迭代器 - 汤宝宝的TODO表迭代器
+type TodoListIterator struct {
+	todoList *TodoList
+	current  int
+}
+
+func (t *TodoListIterator) First() *Todo {
+	t.current = 0
+	if len(t.todoList.todos) == 0 {
+		return nil
+	}
+	return t.todoList.todos[t.current]
+}
+
+func (t *TodoListIterator) Next() *Todo {
+	t.current++
+	if t.isDone() {
+		return nil
+	}
+	return t.todoList.todos[t.current]
+}
+
+func (t *TodoListIterator) isDone() bool {
+	return t.current >= len(t.todoList.todos)
+}
+
+func (t *TodoListIterator) CurrentItem() int {
+	if t.isDone() {
+		return len(t.todoList.todos)
+	}
+	return t.current + 1
+}
+
+// 集合接口
+type Collection interface {
+	CreateIterator() Iterator
+}
+
+// 具体集合 - 汤宝宝的TODO表
+type TodoList struct {
+	todos []*Todo
+}
+
+func (t *TodoList) CreateIterator() Iterator {
+	return &TodoListIterator{
+		todoList: t,
+		current:  0,
+	}
+}
+
+func main() {
+
+	fmt.Println("============= 迭代器模式 =============")
+
+	// 创建TODO表并添加任务
+	todoList := &TodoList{
+		todos: []*Todo{
+			{content: "学习Go语言", done: true},
+			{content: "完成设计模式作业", done: false},
+			{content: "锻炼身体", done: false},
+		},
+	}
+
+	// 创建迭代器
+	iterator := todoList.CreateIterator()
+
+	// 使用迭代器遍历TODO表
+	for item := iterator.First(); !iterator.isDone(); item = iterator.Next() {
+		done := "已完成"
+		if !item.done {
+			done = "未完成"
+		}
+		fmt.Println("当前第", iterator.CurrentItem(), "项任务内容:", item.content, "是否完成:", done)
+	}
+
+	fmt.Println()
+	fmt.Println("=========== 迭代器模式结束 ===========")
+}

python/iterator/main.py

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+"""
+实例：
+汤宝宝有一张TODO表，记录着自己想干的事情。
+"""
+
+from abc import ABC, abstractmethod
+
+
+# 任务结构体 - 迭代器元素
+class Todo:
+    content: str
+    done: bool
+
+    def __init__(self, content: str, done: bool = False):
+        self.content = content
+        self.done = done
+
+
+# 集合接口
+class Collection(ABC):
+    @abstractmethod
+    def CreateIterator(self) -> "Iterator":
+        pass
+
+
+# 具体集合 - 汤宝宝的TODO表
+class TodoList(Collection):
+    todos: list[Todo]
+
+    def __init__(self, todos: list[Todo]):
+        self.todos = todos
+
+    def CreateIterator(self) -> "Iterator":
+        return TodoListIterator(self)
+
+
+# 迭代器接口
+class Iterator(ABC):
+    @abstractmethod
+    def First(self) -> Todo:
+        pass
+
+    @abstractmethod
+    def Next(self) -> Todo | None:
+        pass
+
+    @abstractmethod
+    def isDone(self) -> bool:
+        pass
+
+    @abstractmethod
+    def CurrentItem(self) -> int:
+        pass
+
+
+# 具体迭代器 - 汤宝宝的TODO表迭代器
+class TodoListIterator(Iterator):
+    def __init__(self, todo_list: "TodoList"):
+        self._todo_list = todo_list
+        self._current = 0
+
+    def First(self) -> Todo:
+        self._current = 0
+        return self._todo_list.todos[self._current]
+
+    def Next(self) -> Todo | None:
+        self._current += 1
+        if not self.isDone():
+            return self._todo_list.todos[self._current]
+        return None
+
+    def isDone(self) -> bool:
+        return self._current >= len(self._todo_list.todos)
+
+    def CurrentItem(self) -> int:
+        if self.isDone():
+            return len(self._todo_list.todos)
+        return self._current + 1
+
+
+if __name__ == "__main__":
+    print("============= 迭代器模式 =============")
+
+    # 创建TODO表并添加任务
+    todo_list = TodoList(
+        todos=[
+            Todo("学习Go语言", True),
+            Todo("完成设计模式作业", False),
+            Todo("锻炼身体", False),
+        ]
+    )
+
+    # 创建迭代器
+    iterator = todo_list.CreateIterator()
+
+    # 使用迭代器遍历TODO表
+    item = iterator.First()
+    while not iterator.isDone():
+        done = "已完成" if item and item.done else "未完成"
+        print(
+            f"当前第 {iterator.CurrentItem()} 项任务内容: {item.content if item else ''} 是否完成: {done}"
+        )
+        item = iterator.Next()
+
+    print("\n=========== 迭代器模式结束 ===========")

ts/src/iterator/index.ts

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+/*
+实例：
+汤宝宝有一张TODO表，记录着自己想干的事情。
+*/
+
+// 任务结构体 - 迭代器元素
+interface Todo {
+  content: string;
+  done: boolean;
+}
+
+// 迭代器接口
+interface IIterator {
+  First(): Todo;
+  Next(): Todo;
+  isDone(): boolean;
+  CurrentItem(): number;
+}
+
+// 具体迭代器 - 汤宝宝的TODO表迭代器
+
+class TodoListIterator implements IIterator {
+  todoList: TodoList;
+  current: number;
+  constructor(todoList: TodoList) {
+    this.todoList = todoList;
+    this.current = 0;
+  }
+  First(): Todo {
+    this.current = 0;
+    return this.todoList.todos[this.current];
+  }
+  Next(): Todo {
+    this.current += 1;
+    return this.todoList.todos[this.current];
+  }
+  isDone(): boolean {
+    return this.current >= this.todoList.todos.length;
+  }
+  CurrentItem(): number {
+    if (this.current < 0 || this.current >= this.todoList.todos.length) {
+      return this.todoList.todos.length;
+    }
+    return this.current + 1;
+  }
+}
+
+// 集合接口
+interface ICollection {
+  createIterator(): IIterator;
+}
+
+// 具体集合 - 汤宝宝的TODO表
+class TodoList implements ICollection {
+  todos: Todo[];
+  constructor(todos: Todo[]) {
+    this.todos = todos;
+  }
+
+  createIterator(): IIterator {
+    return new TodoListIterator(this);
+  }
+}
+
+(function () {
+  console.log("============= 迭代器模式 =============");
+
+  // 创建TODO表并添加任务
+  const todoList = new TodoList([
+    { content: "学习Go语言", done: true },
+    { content: "完成设计模式作业", done: false },
+    { content: "锻炼身体", done: false },
+  ]);
+
+  // 创建迭代器
+  const iterator = todoList.createIterator();
+
+  // 使用迭代器遍历TODO表
+  for (
+    let item = iterator.First();
+    !iterator.isDone();
+    item = iterator.Next()
+  ) {
+    console.log(
+      `当前第 ${iterator.CurrentItem()} 项任务内容: ${
+        item ? item.content : ""
+      } 是否完成: ${item && item.done ? "已完成" : "未完成"}`
+    );
+  }
+
+  console.log("\n=========== 迭代器模式结束 ===========");
+})();