std::ranges::elements_view<V,F>::iterator<Const>::operator[]

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General 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)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range conversions
to (C++23)
Range primitives
range_size_trange_difference_trange_value_trange_reference_t	iterator_tconst_iterator_tsentinel_tconst_sentinel_t (C++23)(C++23)	range_const_reference_trange_rvalue_reference_trange_common_reference_t (C++23)	elements_of (C++23)
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range sized_range constant_range (C++23)	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Range factories
empty_viewviews::empty single_viewviews::single	iota_viewviews::iota repeat_viewviews::repeat (C++23)(C++23)	basic_istream_viewviews::istream
Range adaptors
views::all_tviews::all ref_view owning_view as_rvalue_viewviews::as_rvalue (C++23)(C++23) filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while	drop_viewviews::drop drop_while_viewviews::drop_while join_viewviews::join join_with_viewviews::join_with (C++23)(C++23) lazy_split_viewviews::lazy_split split_viewviews::split views::counted common_viewviews::common	reverse_viewviews::reverse as_const_viewviews::as_const (C++23)(C++23) elements_viewviews::elements keys_viewviews::keys values_viewviews::values enumerate_viewviews::enumerate (C++23)(C++23) zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23) views::pairwise_transform (C++23) chunk_viewviews::chunk (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) stride_viewviews::stride (C++23)(C++23) cartesian_product_viewviews::cartesian_product (C++23)(C++23)
Range generators
std::generator (C++23)
Range adaptor objects
Range adaptor closure objects
range_adaptor_closure (C++23)
Helper items
copyable-box movable-box (until C++23)(C++23)	simple-view non-propagating-cache

 

std::ranges::elements_view

Member functions

elements_view::elements_view (C++20)

elements_view::base (C++20)

elements_view::begin (C++20)

elements_view::end (C++20)

elements_view::size (C++20)

Nested classes

Iterator

elements_view::iterator::iterator (C++20)

elements_view::iterator::base (C++20)

elements_view::iterator::operator* (C++20)

elements_view::iterator::operator[] (C++20)

elements_view::iterator::operator++ elements_view::iterator::operator++(int) elements_view::iterator::operator-- elements_view::iterator::operator--(int) elements_view::iterator::operator+= elements_view::iterator::operator-= (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

operator==(elements_view::iterator) operator<(elements_view::iterator) operator>(elements_view::iterator) operator<=(elements_view::iterator) operator>=(elements_view::iterator) operator<=>(elements_view::iterator) (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

operator+(elements_view::iterator) operator-(elements_view::iterator) (C++20)(C++20)

Sentinel

elements_view::sentinel::sentinel (C++20)

elements_view::sentinel::base (C++20)

operator==(elements_view::iterator,elements_view::sentinel) (C++20)

operator-(elements_view::iterator,elements_view::sentinel) (C++20)

 

constexpr decltype(auto) operator[]( difference_type n ) const     requires ranges::random_access_range<Base>;		(since C++20)

Returns an element at specified relative location, as if by /*get-element*/(this->base() + n), where for an expression e, /*get-element*/(e) is

• std::get<N>(*e), if ranges::range_reference_t<Base> is a reference type. Otherwise,
• static_cast<E>(std::get<N>(*e)), where E is std::remove_cv_t<std::tuple_element_t<N, ranges::range_reference_t<Base>>>.

Parameters

n

-

position relative to current location

Return value

The element at displacement n relative to the current location.

Example

Run this code

#include <iostream>
#include <ranges>
#include <string_view>
#include <tuple>
 
int main()
{
    using T = std::tuple<int, char, std::string_view>;
 
    const auto il =
    {
        T{1, 'A', "α"},
        T{2, 'B', "β"},
        T{3, 'C', "γ"},
    };
 
    std::cout << std::views::elements<0>(il)[1] << ' '   // 2
              << std::views::elements<1>(il)[1] << ' '   // B
              << std::views::elements<2>(il)[1] << '\n'; // β
}

Output:

2 B β

See also

operator* (C++20)

accesses the Nth tuple element (public member function)