std::ranges::drop_view<V>::size
constexpr auto size() requires ranges::sized_range<V>; | (1) | (since C++20) |
constexpr auto size() const requires ranges::sized_range<const V>; | (2) | (since C++20) |
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
constautos=ranges::size(base_);
constautoc=static_cast<decltype(s)>(count_);
returns<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
|
(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) |
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