25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.27 Adjacent view [range.adjacent]

25.7.27.1 Overview [range.adjacent.overview]

adjacent_view takes a view and produces a view whose element is a tuple of references to the through elements of the original view.
If the original view has fewer than N elements, the resulting view is empty.
The name views​::​adjacent<N> denotes a range adaptor object ([range.adaptor.object]).
Given a subexpression E and a constant expression N, the expression views​::​adjacent<N>(E) is expression-equivalent to
  • ((void)E, auto(views​::​empty<tuple<>>)) if N is equal to 0 and decltype((E)) models forward_range,
  • otherwise, adjacent_view<views​::​all_t<decltype((E))>, N>(E).
[Example 1: vector v = {1, 2, 3, 4}; for (auto i : v | views::adjacent<2>) { cout << "(" << std::get<0>(i) << ", " << std::get<1>(i) << ") "; // prints (1, 2) (2, 3) (3, 4) } — end example]
Define REPEAT(T, N) as a pack of N types, each of which denotes the same type as T.