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

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Ranges library
Range access
Range conversions
(C++23)

Range primitives



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(until C++23)(C++23)


 
 
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 and the predicate.
2) Move constructs the underlying view from base and the predicate from pred.

[edit] Parameters

base - underlying view
pred - predicate

[edit] Example

#include <array>
#include <iostream>
#include <ranges>
 
int main()
{
    constexpr std::array data{0, -1, -2, 3, 1, 4, 1, 5};
 
    auto view = std::ranges::drop_while_view
    {
        data, [](int x) { return x <= 0; }
    };
 
    for (int x : view)
        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 constructor
constructs a drop_while_view which does not contain an Pred
the drop_while_view is also
not default_initializable