std::ranges::drop_while_view<V,Pred>:: drop_while_view

From cppreference.com
Ranges library
Range adaptors
drop_while_view ( ) requires std:: default_initializable < V > &&
std:: default_initializable < Pred > = default ;
(1) (since C++20)
constexpr explicit drop_while_view ( V base, Pred pred ) ;
(2) (since C++20)

Constructs a drop_while_view .

1) Default constructor. Value-initializes the underlying view base_ and the predicate pred_ .
2) Move constructs the underlying view base_ from base and the predicate pred_ from pred .

Parameters

base - underlying view
pred - predicate

Example

#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

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 constructor
constructs a drop_while_view which does not contain an Pred
the drop_while_view is also
not default_initializable