Re: set_intersection_unsorted

[Bonita Montero]

Am 23.09.2020 um 12:16 schrieb Frederick Gotham:
> #include <type_traits> /* remove_cv, remove_reference */
> #include <algorithm> /* sort */
>
> template<class InputIt1, class InputIt2, class OutputIt>
> OutputIt set_intersection_unsorted(InputIt1 first1, InputIt1 last1,
> InputIt2 first2, InputIt2 last2,
> OutputIt d_first)
> {
> /* The iterators might be plain ol' pointers, e.g. char* */
> /* To keep compatibility with C++11, don't use 'remove_cv_t' */
>
> typedef typename std::remove_cv< typename std::remove_reference<decltype(*first1)>::type >::type type1;
> typedef typename std::remove_cv< typename std::remove_reference<decltype(*first2)>::type >::type type2;
>
> vector<type1> container1(first1,last1);
> vector<type2> container2(first2,last2);
>
> std::sort(container1.begin(), container1.end());
> std::sort(container2.begin(), container2.end());
>
> return std::set_intersection(container1.begin(), container1.end(),
> container2.begin(), container2.end(),
> d_first);
> }

It looks okay to me, but why is the function called set_intersection
*_unsorted* ? Becaus the result of std::set_intersection itself is
sorted.