std::experimental::ranges::find_first_of(3)

NAME
std::experimental::ranges::find_first_of - std::experimental::ranges::find_first_of

Synopsis
   Defined in header <experimental/ranges/algorithm>
   template< InputIterator I1, Sentinel<I1> S1, ForwardIterator I2,
   Sentinel<I2> S2,
   class Proj1 = ranges::identity, class Proj2 = ranges::identity,
   IndirectRelation<projected<I1, Proj1>, (1) (ranges TS)
   projected<I2, Proj2>> Pred = ranges::equal_to<> >
   I1 find_first_of(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred
   = Pred{},
   Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{});
   template< InputRange R1, ForwardRange R2,
   class Proj1 = ranges::identity, class Proj2 = ranges::identity,
   IndirectRelation<projected<ranges::iterator_t<R1>, Proj1>,
   projected<ranges::iterator_t<R2>, Proj2>> Pred = ranges::equal_to<> (2) (ranges TS)
   >
   ranges::safe_iterator_t<R1> find_first_of(R1&& r1, R2&& r2, Pred
   pred = Pred{},
   Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{});
   1) Searches the range [first1, last1) for any of the elements in the range [first2,
   last2), after projecting the ranges with proj1 and proj2 respectively. The projected
   elements are compared using pred.
   2) Same as (1), but uses r1 as the first source range and r2 as the second source
   range, as if using ranges::begin(r1) as first1, ranges::end(r1) as last1,
   ranges::begin(r2) as first2, and ranges::end(r2) as last2.

Parameters
   first1, last1 - the range of elements to examine
   r1 - the range of elements to examine
   first2, last2 - the range of elements to search for
   r2 - the range of elements to search for
   pred - predicate to use to compare the projected elements with
   proj1 - projection to apply to the elements in the first range
   proj2 - projection to apply to the elements in the second range

Return value
   Iterator to the first element in the range [first1, last1) that is equal to an
   element from the range [first2, last2) after projection. If no such element is
   found, an iterator comparing equal to last1 is returned.

Complexity
   At most (S*N) applications of the predicate and each projection, where S =
   distance(last2 - first2) and N = last1 - first1.

Possible implementation
   template< InputIterator I1, Sentinel<I1> S1, ForwardIterator I2, Sentinel<I2> S2,
             class Proj1 = ranges::identity, class Proj2 = ranges::identity,
             IndirectRelation<projected<I1, Proj1>,
                        projected<I2, Proj2>> Pred = ranges::equal_to<> >
   I1 find_first_of(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = Pred{},
                    Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{})
   {
       for (; first1 != last1; ++first1) {
           for (ForwardIt it = first2; it != last2; ++it) {
               if (ranges::invoke(pred, ranges::invoke(proj1, *first1),
                        ranges::invoke(proj2, *it))) {
                   return first1;
               }
           }
       }
       return first1;
   }

Example
    This section is incomplete
    Reason: no example

See also
   find_first_of searches for any one of a set of elements
                 (function template)
   find finds the first element satisfying specific criteria
   find_if (function template)
   find_if_not