std::ranges::adjacent_transform_view<V,F,N>:: size

Returns the number of elements.

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

Parameters

(none)

Return value

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

Example

#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