倒插法实现链表逆置

   1:  void invert(LinkedList &head)

   2:  {

   3:     LinkedList p;//指向当前工作节点

   4:      LinkedList pn;//指向工作节点的前驱节点

   5:   

   6:      //初始化,p指向链表第一个节点，head->next=NULL，即为单独的表头节点。

   7:      p = head->next;

   8:      head->next = NULL; 

   9:   

  10:      while (p)

  11:      {

  12:          pn = p->next;

  13:          p->next = head->next;

  14:          head->next = p;

  15:          p = pn;

  16:      }

  17:   

  18:   

  19:  }