数据结构与算法(C#实现)系列---AVLTree（一）[6]

              if( this.isempty() )

                   throw new exception("my:invalid operation!");

              ((avltree)this.left).rrrotation();

              this.llrotation();

         }

         protected void rrrotation()

         {

              if( this.isempty() )

                   throw new exception("my:invalid operation!");

              avltree avlb=new avltree(this.key);