建立链表哪里出现问题了，求解,谢谢

//建立双向循环链表                                                     
void create_d_list ( struct d_list **headp, int *p )                                                                                                                                                                  
{                                                               
   struct d_list *head = NULL, *tail;                              
   if( p[0] == 0 )                                                     
   *headp = NULL;                                                   
   else
   {                                                           
      head = ( struct d_list * ) malloc ( sizeof( struct d_list ) );            
      //head->data = *p++;   
      head->data = *p;                                             
      tail = head;
      printf("head->data=%d\n",head->data);                                                
      while( *p )
      {                                                      
         tail->next = ( struct d_list * ) malloc ( sizeof ( struct d_list ) );      
         tail->next->prior = tail;   
         //tail = head->prior; //                                    
         //tail = tail->next;   
         head = tail->next;    //                                         
         tail->data = *p++;                                                
      }
      printf("tail->data=%d\n",tail->data);                          
      tail->next = head;                                                
      head->prior = tail;                                             
   }                     
   *headp = head;                                                   
}

[ 本帖最后由 henyue 于 2008-8-15 15:49 编辑 ]

“while( *p )
      {                                                      
         tail->next = ( struct d_list * ) malloc ( sizeof ( struct d_list ) );      
         tail->next->prior = tail;   
         //tail = head->prior; //                                    
         //tail = tail->next;   
         head = tail->next;    //                                         
         tail->data = *p++;                                                
      }
”
把"   head = tail->next;    //                                         "  换成“tail=tail->next”  试下，      


另外，  while(*p)  这个判断法肯定有问题

那应该怎么改呢，可以说下吗