数据结构学习（C++）——单链表（定义与实现）[16]

       }

       void insertbefore(node<type> *p)

       {

              p->link = current;

              prior->link = p;

              prior = p;

       }     

       void lastinsert(node<type> *p)

       {

              p->link = null;

              last->link = p;

              last = p;

       }

       node<type> *premove()

       {     

              if (current != null && prior != null)

              {

                     node<type> *p = current;