DS-单链表：单链表尾删法

一、单链表尾删法

思路：

• 用指针ptail遍历链表，pre记录ptail前驱，遍历的条件是ptai->pnext!=NULL
• 遍历结束，ptai指向链表尾结点，pre指向尾结点前驱
• 释放尾结点，将pre结点的指针域置空

代码

/// @brief 删除链表尾结点，即尾删法
/// @param plist 链表指针
/// @return 返回是否删除成功标志
/// @retval ERROR(0)：链表不存在或链表为空，不可操作
/// @retval OK(1)：删除成功
status xxx_pop_back(myLinkList* plist)
{
    if (plist == NULL)
    {
        return ERROR;
    }
    return xxx_pop_back_(plist->phead);
}
status xxx_pop_back_(myLNode* phead)
{
    if (phead == NULL || phead->pnext == NULL)
    {
        return ERROR;
    }
    myLNode* ptail = phead;
    myLNode* pre = NULL;
    /// 循环让ptail最终指向尾结点,pre指向尾结点前驱
    while (ptail->pnext != NULL)
    {
        pre = ptail;
        ptail = ptail->pnext;
    }
    pre->pnext = NULL;
    free(ptail);
    ptail = NULL;
    return OK;
}