以双向循环链表结构存储线性表。

⑴ 输入数据元素，以先进先出形式创建双向循环链表

⑵ 销毁双向循环链表

⑶ 线性表置空

⑷ 求线性表长度

⑸ 在第i个数据元素前插入新的元素

⑹ 删除元素（按指定元素序号和元素值2种方式）

⑺ 显示线性表中的全部元素

⑻ 求最大元素的值和平均值

⑼ 就地逆置双向循环链表（不允许将结点中的值互相交换）-Two-way circular linked list structure to store the linear form. ⑴ input data elements to create a bi-directional FIFO form circular linked list ⑵ destruction of two-way circular linked list ⑶ linear form blank ⑷ ⑸ of linear table length data elements in the i before the insertion of new elements ⑹ delete elements (elements specified serial number and element values ​ ​ are 2 ways) ⑺ table shows all the elements of linear ⑻ seek the maximum value of the element and the average ⑼ way circular linked list in place against the home (allowed values ​ ​ of the nodes in the exchange)