std::ranges::drop_view<V>::drop_view
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Ranges library
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(C++23)
std::ranges::drop_view
drop_view::drop_view
(C++26)
drop_view() requires std::default_initializable <V> = default;
(1)
(since C++20)
constexpr explicit drop_view( V base, ranges::range_difference_t <V> count );
(2)
(since C++20)
Constructs a drop_view.
1) Default constructor. Value-initializes the underlying view
base_ and initializes the count count_ to 0. After construction, base() returns a copy of V() and size() equals to the size of the underlying view.2) Initializes the underlying view
base_ with std::move(base) and the count count_ with count. After construction, base() returns a copy of base and size() returns ranges::size (base) - count if the size of base is not less than count, or 0 otherwise.[edit] Parameters
base
-
the underlying view
count
-
number of elements to skip
[edit] Example
Run this code
#include <algorithm> #include <array> #include <iostream> #include <iterator> #include <ranges> int main() { constexpr std::array hi{'H', 'e', 'l', 'l', 'o', ',', ' ', 'C', '+', '+', '2', '0'}; std::ranges::for_each (hi, [](const char c){ std::cout << c; }); std::cout << '\n'; constexpr auto n = std::distance (hi.cbegin(), std::ranges::find (hi, 'C')); auto cxx = std::ranges::drop_view {hi, n}; std::ranges::for_each (cxx, [](const char c){ std::cout << c; }); std::cout << '\n'; }
Output:
Hello, C++20 C++20
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 3714 (P2711R1) |
C++20 | the multi-parameter constructor was not explicit | made explicit |