单向链表的升序建立，降序建立，删除，插入，计数，清空（输入是以文件的形式，请下载者自行写输入文件并与此程序放在同一个文件夹下．）-The establishment of a one-way linked list of ascending, descending to establish, delete, insert, count, empty (input is the form of documents, please down