Listing 4: Improved Template Function reverse

template<class  BidIt>  inline
    void  reverse(BidIt  first,  BidIt  last)
    {_Reverse(first,  last,
                            iterator_category(first));  }
template<class  BidIt>  inline
    void  _Reverse(BidIt  first,  BidIt  last,
        bidirectional_iterator_tag)
    {for  (;  first  !=  last  &&  first  !=  --last;  ++first)
        iter_swap(first,  last);  }
template<class  RanIt>  inline
    void  _Reverse(RanIt  first,  RanIt  last,
        random_access_iterator_tag)
    {for  (;  first  <  last;  ++first)
        iter_swap(first,  --last);  }
//End of File