2026年3月 GESP C++ 5级单选题第2题｜真题与答案解析

双向循环链表中要在结点 p 之前插入新结点 s（均非空），以下指针操作正确的是（）。

cpp s -> next = p;                                                       p -> prev = s;                                                       p -> next = s;                                                       s -> prev = p;

cpp s -> prev = p;                                                       s -> next = p -> next;                                               p -> next -> prev = s;                                               p -> next = s;

cpp s -> next = p;                                                       s -> prev = p->prev;                                                 p -> prev -> next = s;                                               p -> prev = s;

cpp s -> next = p;                                                       s -> prev = nullptr;                                                 p -> prev = s;