单链表的基本操作，创建一个广义表+判空+显示+长度， 广义表的复制+插入+深度+删除+销毁，打印广义表中的原子。-The basic operation of a single list, create a generalized table+ empty+ show+ the length of sentence, the generalized form of the copy+ delete+ insert+ depth+ destruction, print generalized li