程序填空题：单链表逆转

下列代码的功能是返回带头结点的单链表`L`的逆转链表。

```c++
List Reverse( List L )
{
Position Old_head, New_head, Temp;
New_head = NULL;
Old_head = L->Next;

while ( Old_head ) {
Temp = Old_head->Next;
@@[Old_head->Next = New_head](3);
New_head = Old_head;
Old_head = Temp;
}
@@[L->Next = New_head](3);
return L;
}
```





答案：
第1空：Old_head->Next = New_head

第2空：L->Next = New_head