线性表的顺序（链式）存储表示及实现

　　 3. 从单链表中删除指定的元素x，若x在单链表中不存在，给出提示信息。

要求： （1）指定的值x由键盘输入；（2）程序能处理空链表的情况。-The order of the linear form (chain) store that and the realization of 3. From a single list to remove the element x, if x in a single linked list does not exist in the given message. Requirements: (1) designated by the keyboard input value x　(2) procedures to deal with the case of empty list.