Re: STL iterators

[Andre Poenitz]

Ulrich Eckhardt <doomster@knuut.de> wrote:
> Gelu Ionescu wrote:
>> My hope is to detect a substring in a string using 2 string::iterators 
>> it1 & it2.
> 
> Don't, std::string has other methods for that. Otherwise, you would need an
> algorithm that searches one sequence within another sequence, which is
> easy to write but AFAIK not part of the C++ standardlibrary 


Shouldn't the following do the trick?

  /**
   *  @brief Search a sequence for a matching sub-sequence.
   *  @param  first1  A forward iterator.
   *  @param  last1   A forward iterator.
   *  @param  first2  A forward iterator.
   *  @param  last2   A forward iterator.
   *  @return   The first iterator @c i in the range
   *  @p [first1,last1-(last2-first2)) such that @c *(i+N) == @p *(first2+N)
   *  for each @c N in the range @p [0,last2-first2), or @p last1 if no
   *  such iterator exists.
   *
   *  Searches the range @p [first1,last1) for a sub-sequence that compares
   *  equal value-by-value with the sequence given by @p [first2,last2) and
   *  returns an iterator to the first element of the sub-sequence, or
   *  @p last1 if the sub-sequence is not found.
   *
   *  Because the sub-sequence must lie completely within the range
   *  @p [first1,last1) it must start at a position less than
   *  @p last1-(last2-first2) where @p last2-first2 is the length of the
   *  sub-sequence.
   *  This means that the returned iterator @c i will be in the range
   *  @p [first1,last1-(last2-first2))
  */
  template<typename _ForwardIter1, typename _ForwardIter2>
    _ForwardIter1
    search(_ForwardIter1 __first1, _ForwardIter1 __last1,
           _ForwardIter2 __first2, _ForwardIter2 __last2)

> All this has nothing to do with the GCC's C++ compiler though.

Example was taken from a gcc installation ;-}

Andre'