constexpr auto size() requires ranges::sized_range<InnerView>; | (since C++23) | |
constexpr auto size() const requires ranges::sized_range<const InnerView>; | (since C++23) |
Returns the number of elements.
Let inner_ be the underlying object of type InnerView (that is the ranges::adjacent_view<V,N>).
return inner_.size();.(none).
The number of elements, may be 0 if the size of the underlying view V is less than N.
A link to test: Compiler Explorer/g++-13.
#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);
}|
(C++20) | returns an integer equal to the size of a range (customization point object) |
|
(C++20) | returns a signed integer equal to the size of a range (customization point object) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/ranges/adjacent_transform_view/size