NAME¶

std::ranges::views::slide,std::ranges::slide_view - std::ranges::views::slide,std::ranges::slide_view

Synopsis¶

Defined in header <ranges>
template< ranges::forward_range V >

requires ranges::view<V> (1) (since C++23)
class slide_view

: public ranges::view_interface<slide_view<V>>
namespace views {

inline constexpr /* unspecified */ slide = /* unspecified (2) (since C++23)
*/;

}
Call signature
template< ranges::viewable_range R >
constexpr ranges::view auto slide( R&& r, (since C++23)
ranges::range_difference_t<R> n );
template< class DifferenceType >
constexpr /* range adaptor object */ slide( DifferenceType&& (since C++23)
n );
Helper concepts
template< class V >

concept __slide_caches_nothing = (3) (exposition only*)

ranges::random_access_range<V> && ranges::sized_range<V>;
template< class V >

concept __slide_caches_last =
!__slide_caches_nothing<V> && (4) (exposition only*)

ranges::bidirectional_range<V> &&
ranges::common_range<V>;
template< class V >

concept __slide_caches_first = (5) (exposition only*)

!__slide_caches_nothing<V> && !__slide_caches_last<V>;

1) slide_view is a range adaptor that takes a view and a number n and produces a
view whose m ^th element (a "window") is a view over the m ^th through (m + n -
1) ^th elements of the original view.
Let s be the size of the original view. Then the size of produced view is:
* s - n + 1, if s >= n,
* 0 otherwise, and the resulting view is empty.
2) The name views::slide denotes a RangeAdaptorObject. Given subexpressions e and n,
the expression views::slide(e, n) is expression-equivalent to slide_view(e, n).

If n is not greater than 0, the behavior is undefined.

slide_view always models forward_range, and models bidirectional_range,
random_access_range, or sized_range if adapted view type models the corresponding
concept.

Member functions¶

constructor constructs a slide_view
(C++23) (public member function)
begin returns an iterator to the beginning
(C++23) (public member function)
end returns an iterator or a sentinel to the end
(C++23) (public member function)
size returns the number of elements. Provided only if the underlying
(C++23) (adapted) range satisfies sized_range.
(public member function)
Inherited from std::ranges::view_interface
empty returns whether the derived view is empty. Provided if it satisfies
(C++20) sized_range or forward_range.
(public member function of std::ranges::view_interface<D>)
cbegin returns a constant iterator to the beginning of the range.
(C++23) (public member function of std::ranges::view_interface<D>)
cend returns a sentinel for the constant iterator of the range.
(C++23) (public member function of std::ranges::view_interface<D>)
operator bool returns whether the derived view is not empty. Provided if
(C++20) ranges::empty is applicable to it.
(public member function of std::ranges::view_interface<D>)
front returns the first element in the derived view. Provided if it
(C++20) satisfies forward_range.
(public member function of std::ranges::view_interface<D>)
back returns the last element in the derived view. Provided if it satisfies
(C++20) bidirectional_range and common_range.
(public member function of std::ranges::view_interface<D>)
operator[] returns the n^th element in the derived view. Provided if it satisfies
(C++20) random_access_range.
(public member function of std::ranges::view_interface<D>)

Deduction guides

Nested classes

iterator the iterator type
(C++23) (exposition-only member class template*)
sentinel the sentinel type used when slide_view is not a common_range
(C++23) (exposition-only member class template*)

Helper templates

template< class V >

inline constexpr bool ranges::enable_borrowed_range<slide_view<V>> = (since C++23)

ranges::enable_borrowed_range<V>;

This specialization of ranges::enable_borrowed_range makes slide_view satisfy
borrowed_range when the underlying view satisfies it.

Notes¶

There are similarities between ranges::adjacent_view and ranges::slide_view:

* Both create a "sliding window" of size N.
* Both have the same size S - N + 1, where S is the size of an adapted view such
that S >= N > 0.

The differences between these adapters are:

View adaptor value_type The window size N
ranges::adjacent_view A std::tuple object A template parameter
ranges::slide_view A range A runtime parameter

Feature-test macro Value Std Feature
__cpp_lib_ranges_slide 202202L (C++23) std::ranges::slide_view

Example¶

// Run this code

#include <algorithm>
#include <iostream>
#include <ranges>

auto print_subrange = [](std::ranges::viewable_range auto&& r)
{
std::cout << '[';
for (char space[]{0,0}; auto elem : r)
std::cout << space << elem, *space = ' ';
std::cout << "] ";
};

int main()
{
const auto v = {1, 2, 3, 4, 5, 6};

std::cout << "All sliding windows of width:\n";
for (const unsigned width : std::views::iota(1U, 1U + v.size()))
{
auto const windows = v | std::views::slide(width);
std::cout << "W = " << width << ": ";
std::ranges::for_each(windows, print_subrange);
std::cout << '\n';
}
}

Output:¶

All sliding windows of width W:
W = 1: [1] [2] [3] [4] [5] [6]
W = 2: [1 2] [2 3] [3 4] [4 5] [5 6]
W = 3: [1 2 3] [2 3 4] [3 4 5] [4 5 6]
W = 4: [1 2 3 4] [2 3 4 5] [3 4 5 6]
W = 5: [1 2 3 4 5] [2 3 4 5 6]
W = 6: [1 2 3 4 5 6]

References¶

* C++23 standard (ISO/IEC 14882:2023):

* 26.7.29 Slide view [range.slide]

See also¶

ranges::adjacent_view a view consisting of tuples of references to adjacent elements
views::adjacent of the adapted view
(C++23) (class template) (range adaptor object)
ranges::chunk_view a range of views that are N-sized non-overlapping successive
views::chunk chunks of the elements of another view
(C++23) (class template) (range adaptor object)