std::span<T,Extent>::rbegin, std::span<T,Extent>::crbegin

 

C++

Compiler support

Freestanding and hosted

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Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

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Diagnostics library

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Strings library

Containers library

Iterators library

Ranges library (C++20)

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Filesystem library (C++17)

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Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

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list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

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std::span

Member functions

span::span

span::operator=

Element access

span::front

span::back

span::at (C++26)

span::operator[]

span::data

Iterators

span::beginspan::cbegin (C++23)

span::endspan::cend (C++23)

span::rbeginspan::crbegin (C++23)

span::rendspan::crend (C++23)

Observers

span::empty

span::size

span::size_bytes

Subviews

span::first

span::last

span::subspan

Non-member functions

as_bytesas_writable_bytes

Non-member constant

dynamic_extent

Deduction guides

 

constexpr reverse_iterator rbegin() const noexcept;	(1)	(since C++20)
constexpr const_reverse_iterator crbegin() const noexcept;	(2)	(since C++23)

Returns a reverse iterator to the first element of the reversed span. It corresponds to the last element of the non-reversed span. If the span is empty, the returned iterator is equal to rend().

Parameters

(none)

Return value

Reverse iterator to the first element.

Complexity

Constant.

Notes

The underlying iterator of the returned reverse iterator is the end iterator. Hence the returned iterator is invalidated if and when the end iterator is invalidated.

Example

Run this code

#include <algorithm>
#include <iostream>
#include <iterator>
#include <span>
 
int main()
{
    constexpr std::span<const char> code{"@droNE_T0P_w$s@s#_SECRET_a,p^42!"};
 
    auto hack = [](const unsigned O) { return O - 0141 < 120; };
 
    std::copy_if(code.rbegin(), code.rend(),
        std::ostream_iterator<const char>(std::cout), hack);
 
    std::cout << '\n';
}

Output:

password

See also

rendcrend (C++23)	returns a reverse iterator to the end (public member function)
rbegincrbegin (C++14)	returns a reverse iterator to the beginning of a container or array (function template)