std::ranges::stride_view<V>::size

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< cpp‎ | ranges‎ | stride view
 
 
Ranges library
Range adaptors
 
 
constexpr auto size() requires ranges::sized_range<V>;
(since C++23)
constexpr auto size() const requires ranges::sized_range<const V>;
(since C++23)

Returns the number of elements.

Let base_ be the underlying view and stride_ be the stored stride value. Equivalent to:

return /*to-unsigned-like*/(/*div-ceil*/(ranges::distance(base_), stride_));

Parameters

(none)

Return value

The number of elements. The returned value is calculated as if by expression

(ranges::size(base_) / stride_) + ((ranges::size(base_) % stride_ ? 1 : 0).

Example

#include <forward_list>
#include <ranges>
 
int main()
{
    namespace vs = std::views;
    constexpr static auto v = {1, 2, 3, 4, 5};
    static_assert
    (
        vs::stride(v, 1).size() == 5 and
        vs::stride(v, 2).size() == 3 and
        vs::stride(v, 3).size() == 2 and
        vs::stride(v, 4).size() == 2 and
        vs::stride(v, 5).size() == 1 and
        vs::stride(v, 6).size() == 1
    );
 
    std::forward_list list{v};
//  auto s = vs::stride(list, 2).size(); // Error: not a sized_range
}

See also

returns an integer equal to the size of a range
(customization point object)
returns a signed integer equal to the size of a range
(customization point object)