std::ranges::drop_view<V>:: size

Let base_ be the underlying view, count_ be the stored count (the number passed to the constructor, or ​ 0 ​ if * this is default constructed). Equivalent to

const auto s = ranges:: size ( base_ ) ;
const auto c = static_cast < decltype ( s ) > ( count_ ) ;
return s < c ? 0 : s - c ;

Return value

The number of elements.

Example

#include <array>
#include <ranges>
int main()
{
    constexpr std::array a{42, 43, 44};
    static_assert
    (
        std::ranges::drop_view{std::views::all(a), 0}.size() == 3 &&
        std::ranges::drop_view{std::views::all(a), 1}.size() == 2 &&
        std::ranges::drop_view{std::views::all(a), 2}.size() == 1 &&
        std::ranges::drop_view{std::views::all(a), 3}.size() == 0 &&
        std::ranges::drop_view{std::views::all(a), 4}.size() == 0
    );
}

See also