[range.adjacent.overview]

# 25 Ranges library [[ranges]](./#ranges)

## 25.7 Range adaptors [[range.adaptors]](range.adaptors#range.adjacent.overview)

### 25.7.27 Adjacent view [[range.adjacent]](range.adjacent#overview)

#### 25.7.27.1 Overview [range.adjacent.overview]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L12539)

adjacent_view takes a view and
produces a view whose Mth element is
a tuple of references to
the Mth through (M+N−1)th elements of
the original view[.](#1.sentence-1)

If the original view has fewer than N elements, the resulting view is empty[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L12547)

The name views​::​adjacent<N> denotes
a range adaptor object ([[range.adaptor.object]](range.adaptor.object "25.7.2 Range adaptor objects"))[.](#2.sentence-1)

Given a subexpression E and a constant expression N,
the expression views​::​adjacent<N>(E) is expression-equivalent to

- [(2.1)](#2.1)

((void)E, auto(views​::​empty<tuple<>>)) if N is equal to 0 anddecltype((E)) models [forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]"),

- [(2.2)](#2.2)

otherwise, adjacent_view<views​::​all_t<decltype((E))>, N>(E)[.](#2.sentence-2)

[*Example [1](#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*]

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L12572)

Define *REPEAT*(T, N) as a pack of N types,
each of which denotes the same type as T[.](#3.sentence-1)