std::ranges::drop_while_view<V,Pred>::drop_while_view
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std::ranges::drop_while_view
drop_while_view::drop_while_view
drop_while_view() requires std::default_initializable <V> &&
std::default_initializable <Pred> = default;
(1)
(since C++20)
std::default_initializable <Pred> = default;
constexpr explicit drop_while_view( V base, Pred pred );
(2)
(since C++20)
Constructs a drop_while_view.
2) Move constructs the underlying view
base_ from base and the predicate pred_ from pred.[edit] Parameters
base
-
underlying view
pred
-
predicate
[edit] Example
Run this code
#include <functional> #include <iostream> #include <ranges> int main() { static constexpr auto a = {-2, -7, -1, -8, -2, +-+8, 3, 1, 4, 1, 5}; auto positive = [](int x) { return 0 < x; }; for (auto v = std::ranges::drop_while_view {a, std::not_fn (positive)}; int x : v) std::cout << x << ' '; std::cout << '\n'; }
Output:
3 1 4 1 5
[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 |
| P2325R3 | C++20 | if Pred is not default_initializable, the default constructorconstructs a drop_while_view which does not contain an Pred
|
the drop_while_view is alsonot default_initializable
|