NAME¶

std::ranges::drop_view::drop_view - std::ranges::drop_view::drop_view

Synopsis¶

drop_view() requires std::default_initializable<V> = default; (1) (since C++20)
constexpr explicit drop_view( V base, (2) (since C++20)
ranges::range_difference_t<V> count );

Constructs a drop_view.

1) Default constructor. Value-initializes the underlying view and initializes the
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 with std::move(base) and the 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.

Parameters¶

base - the underlying view
count - number of elements to skip

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

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 C++20 the multi-parameter constructor was not made explicit
(P2711R1) explicit