cppdraft_translate/cppdraft/range/reverse/overview.md

[range.reverse.overview]

25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.21 Reverse view [range.reverse]

25.7.21.1 Overview [range.reverse.overview]

1

#

reverse_view takes a bidirectional view and produces another view that iterates the same elements in reverse order.

2

#

The name views​::​reverse denotes a range adaptor object ([range.adaptor.object]).

Given a subexpression E, the expressionviews​::​reverse(E) is expression-equivalent to:

• (2.1)

  If the type of E is a (possibly cv-qualified) specialization of reverse_view, then E.base().

• (2.2)

  Otherwise, if the type of E is cv subrange<reverse_iterator, reverse_iterator, K> for some iterator type I and value K of type subrange_kind,

  • (2.2.1)

if K is subrange_kind​::​sized, thensubrange<I, I, K>(E.end().base(), E.begin().base(), E.size());

• (2.2.2)

otherwise, subrange<I, I, K>(E.end().base(), E.begin().base()).

However, in either case E is evaluated only once.

• (2.3)

  Otherwise, reverse_view{E}.

3

#

[Example 1: vector is {0,1,2,3,4};for (int i : is | views::reverse) cout << i << ' '; // prints 4 3 2 1 0 — end example]