creating an iterator to search a vector of list<T>

[monarch_dodra]

I have a template class defined as the following:

template <class T, class HF>
class HashTable
{
   private:

   vector<list<T> > bucket;

  public:

  //public methods
  bool find(const T&) const;
  
};

What I'm trying to do is create an iterator to traverse the contents of bucket.

I've tried a few variations of defining a list iterator, such as

list<T>::const_iterator it;

but haven't found anything that is correct? Any ideas?

Bucket is a vector, so your iterator has to be a vector iterator:

vector<list<T> >::const_iterator it

Each iterator will point to a list. If you want to iterate on the items in that list, create a list iterator:

vector<list<T> >::const_iterator itVect = bucket.begin();
vector<list<T> >::const_iterator itVectEnd = bucket.end();
for ( ; itVect != itVectEnd ; ++itVect)
{
     list<T>const_iterator itList = itVect->begin();
     list<T>const_iterator itListEnd = itVect->end();
     for ( ; itList != itListEnd ; ++itList )
    {
        //Do things with itListEnd
    }

}

If what you wanted was an actual new iterator type that traverses both, with HashTable::begin() defined as bucket.begin()->begin(), and HashTable::end() defined as (bucket.end()-1)->end(), well I'm afraid you'll have to write your entire own iterator class. I know there are some things in boost that can speed up the process (for example, if you write operator+=, there is a boost class which will automatically generate operator+), I wouldn't their names, and I don't know if they are worth the trouble.

Does that answer your question?