advance function: It is used to increment an iterator.
template <class InIter, class Dist> void advance(InIter &itr, Dist d);
distance function: It is used to return number of elements between I and j.
template <class II> distance(II i, II j);
where, II is input iterator.
failed function: failed function returns true in case of failure. It is a member function of ostreambuf_iterator class.
bool failed( ) const throw( );
equal function: equal function is a member function of istreambuf_iterator class. It returns true if iterator and obj points end of stream.
bool equal(istreambuf_iterator<CharType, Attr> &obj);
base function: It is a member function of reverse_iterator class. It is used to return iterator to current location.
Iter base( ) const;