std::set<Key,Compare,Allocator>::rbegin, std::set<Key,Compare,Allocator>::crbegin

 

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)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

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)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::set

Member functions

set::set set::~set            set::operator= set::get_allocator

Iterators set::beginset::cbegin (C++11) set::endset::cend (C++11) set::rbeginset::crbegin (C++11)   set::rendset::crend (C++11) Capacity set::size set::max_size set::empty Observers set::key_comp set::value_comp Modifiers set::clear set::erase set::swap set::extract (C++17) set::merge (C++17) set::insert set::insert_range (C++23) set::emplace (C++11) set::emplace_hint (C++11) Lookup set::count set::find set::contains (C++20)    set::equal_range set::lower_bound set::upper_bound

Non-member functions

operator==operator<=> (C++20) std::swap(std::set) erase_if(std::set) (C++20)   operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)

Deduction guides(C++17)

 

reverse_iterator rbegin();	(1)	(noexcept since C++11)
const_reverse_iterator rbegin() const;	(2)	(noexcept since C++11)
const_reverse_iterator crbegin() const noexcept;	(3)	(since C++11)

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

Parameters

(none)

Return value

Reverse iterator to the first element.

Complexity

Constant.

Notes

Because both iterator and const_iterator are constant iterators (and may in fact be the same type), it is not possible to mutate the elements of the container through an iterator returned by any of these member functions.

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.

libc++ backports crbegin() to C++98 mode.

Example

Run this code

#include <iostream>
#include <set>
 
int main()
{
    std::set<unsigned> rep{1, 2, 3, 4, 1, 2, 3, 4};
 
    for (auto it = rep.crbegin(); it != rep.crend(); ++it)
    {
        for (auto n = *it; n > 0; --n)
            std::cout << "⏼" << ' ';
        std::cout << '\n';
    }
}

Output:

⏼ ⏼ ⏼ ⏼
⏼ ⏼ ⏼
⏼ ⏼
⏼

See also

rendcrend (C++11)	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)