完成一个带头结点的单链表建立，实现初始化、求表长、取元素、按值查找、单链表的插入、删除、遍历访问等基本操作。 在此基础上，利用原链表结点空间实现逆转并输出结果。-Complete a lead list of single-linked list of the establishment, to achieve initialization, the length of the table, take the elements, according to the value of singl