std::ranges::drop_view<V>::begin

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range primitives
iterator_tsentinel_t	range_size_trange_difference_t	range_value_t	range_reference_trange_rvalue_reference_t
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range sized_range	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Semiregular wrapper
Factories
empty_viewviews::empty	single_viewviews::single	iota_viewviews::iota	views::counted
Adaptors
views::all_tviews::all join_viewviews::join take_viewviews::take basic_istream_viewistream_view	ref_view                                split_viewviews::split take_while_viewviews::take_while elements_viewviews::elements	common_viewviews::common transform_viewviews::transform drop_viewviews::drop keys_viewviews::keys	reverse_viewviews::reverse filter_viewviews::filter drop_while_viewviews::drop_while values_viewviews::values

 

std::ranges::drop_view

Member functions

drop_view::drop_view

drop_view::base

drop_view::begin

drop_view::end

drop_view::size

Deduction guides

 

constexpr auto begin()   requires (!(__SimpleView<V> && ranges::random_access_range<V>));	(1)	(since C++20)
constexpr auto begin()   requires ranges::random_access_range<const V>;	(2)	(since C++20)

Returns an iterator to the first element of the drop_view, that is, an iterator to the N-th element of the underlying view, or to the end of the underlying view if it has less than N elements.

1) If V is not a random_access_range, in order to provide the amortized constant time complexity required by the range concept, this function caches the result within the drop_view object for use on subsequent calls.

Parameters

(none)

Return value

ranges::next(ranges::begin(base_), count_, ranges::end(base_)), where base_ is the underlying view, and count_ is the number of elements to skip

Example

Run this code

#include <algorithm>
#include <array>
#include <iostream>
#include <iterator>
#include <ranges>
 
int main()
{
    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';
 
    const auto c = std::distance(hi.begin(), std::ranges::find(hi, 'C'));
    auto cxx = std::ranges::drop_view{ hi, c };
    std::cout << "*drop_view::begin() == '" << *cxx.begin() << "'\n";
 
//  *cxx.begin() = 'c'; // do not modify an original object using a 'view'
 
    for (char c : cxx) { std::cout << c; }
    std::cout << '\n';
}

Output:

Hello, C++20!
*drop_view::begin() == 'C'
C++20!

See also

end	returns an iterator or a sentinel to the end (public member function)