NAME¶

std::ranges::views::stride,std::ranges::stride_view - std::ranges::views::stride,std::ranges::stride_view

Synopsis¶

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

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

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

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

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

1) stride_view is a range adaptor that takes a view and a number n and produces a
view, that consists of elements of the original view by advancing over n elements at
a time. This means that each m^th element of the produced view is (n * i)^th element
of the original view, for some non-negative index i. The elements of the original
view, whose "index" is not a multiple of n, are not present in the produced view.
Let S be the size of the original view. Then the size of produced view is:
* (S / n) + (S % n ? 1 : 0), if S >= n; otherwise,
* 1, if S > 0; otherwise,
* 0, and the resulting view is empty.
2) The name views::stride denotes a RangeAdaptorObject. Given subexpressions e and
n, the expression views::stride(e, n) is expression-equivalent to stride_view(e, n).
The n must be greater than 0, otherwise the behavior is undefined.

stride_view always models input_range, and models forward_range,
bidirectional_range, random_access_range, and/or sized_range, if adapted view type V
models the corresponding concept. stride_view<V> models common_range whenever the
underlying view V does.

Member functions¶

constructor constructs a stride_view
(C++23) (public member function)
stride returns the stored stride value
(C++23) (public member function)
base returns a copy of the underlying (adapted) 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*)

Helper templates

template< class V >

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

ranges::enable_borrowed_range<V>;

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

Notes¶

Feature-test macro Value Std Feature
__cpp_lib_ranges_stride 202207L (C++23) std::ranges::stride_view

Example¶

// Run this code

#include <algorithm>
#include <iostream>
#include <ranges>
#include <string_view>
using namespace std::literals;

void print(std::ranges::viewable_range auto&& v, std::string_view separator = " ")
{
for (auto const& x : v)
std::cout << x << separator;
std::cout << '\n';
}

int main()
{
print(std::views::iota(1, 13) | std::views::stride(3));
print(std::views::iota(1, 13) | std::views::stride(3) | std::views::reverse);
print(std::views::iota(1, 13) | std::views::reverse | std::views::stride(3));

print("0x0!133713337*x//42/A$@"sv | std::views::stride(0B11) |
std::views::transform([](char O) -> char { return 0100 | O; }),
"");
}

Output:¶

1 4 7 10
10 7 4 1
12 9 6 3
password

References¶

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

* 26.7.31 Stride view [range.stride]

See also¶

ranges::slide_view a view whose M^th element is a view over the M^th through (M +
views::slide N - 1)^th elements of another 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)
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::filter_view a view that consists of the elements of a range that satisfies
views::filter a predicate
(C++20) (class template) (range adaptor object)