NAME¶

std::ranges::adjacent_transform_view::size - std::ranges::adjacent_transform_view::size

Synopsis¶

constexpr auto size() requires ranges::sized_range<InnerView>; (since C++23)
constexpr auto size() const requires ranges::sized_range<const (since C++23)
InnerView>;

Returns the number of elements.

Let inner_ be the underlying object of type InnerView (that is the
ranges::adjacent_view<V,N>).

1,2) Equivalent to return inner_.size();.

Parameters¶

(none)

Return value¶

The number of elements, may be 0 if the size of the underlying view V is less than
N.

Example¶

// Run this code

#include <ranges>

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

auto f = [](auto...) { return 0; }; // dummy

constexpr int width1 {4};
constexpr auto view1 = v | std::views::adjacent_transform<width1>(f);
static_assert(view1.size() == 3);
static_assert(view1.size() == (v.size() - width1 + 1));

constexpr int width2 {8};
constexpr auto view2 = v | std::views::adjacent_transform<width2>(f);
// window is too wide, so view2 has no elements:
static_assert(view2.size() == 0);
}

See also¶

ranges::size returns an integer equal to the size of a range
(C++20) (customization point object)
ranges::ssize returns a signed integer equal to the size of a range
(C++20) (customization point object)