笔试题2：怎样把一个链表掉个顺序（注意链表为空和边界值）

void reverselist(type &phead1){

       type phead2,pbuffer;

       phead2=null;

       pbuffer=phead1;

       while (pbuffer!=null){

               phead1=phead1->next;

               pbuffer->next=phead2;

               phead2=pbuffer;

               pbuffer=phead1;

       }

        phead1=phead2;

}

用3个指针实现链表的倒置，phead1指向未倒置的链表头，phead2指向已倒置的链表的头，pbuffer中间变量。