std::rbegin,std::crbegin

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General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
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Date and time library
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Iterator library

Iterator concepts

indirectly_readable (C++20)
indirectly_writable (C++20)
weakly_incrementable (C++20)
incrementable (C++20)
is-integer-like is-signed-integer-like (C++20)(C++20)

sentinel_for (C++20)
sized_sentinel_for (C++20)
input_iterator (C++20)
output_iterator (C++20)
input_or_output_iterator (C++20)

forward_iterator (C++20)
bidirectional_iterator (C++20)
random_access_iterator (C++20)
contiguous_iterator (C++20)

Iterator primitives

input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag

(C++20)

iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t

(C++20)(C++20)(C++20)(C++23)(C++20)(C++20)

iterator (deprecated in C++17)
iterator_traits
incrementable_traits (C++20)
indirectly_readable_traits (C++20)

Algorithm concepts and utilities

Indirect callable concepts

indirectly_unary_invocableindirectly_regular_unary_invocable

(C++20)(C++20)

indirect_unary_predicate (C++20)
indirect_binary_predicate (C++20)

indirect_equivalence_relation (C++20)
indirect_strict_weak_order (C++20)

Common algorithm requirements

indirectly_movable (C++20)
indirectly_movable_storable (C++20)
indirectly_copyable (C++20)

indirectly_copyable_storable (C++20)
indirectly_swappable (C++20)
indirectly_comparable (C++20)

permutable (C++20)
mergeable (C++20)
sortable (C++20)

(C++20)

(C++20)

(C++26)

reverse_iterator
make_reverse_iterator (C++14)
move_iterator (C++11)
make_move_iterator (C++11)
default_sentinel_tdefault_sentinel (C++20)(C++20)
unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)

front_insert_iterator
back_insert_iterator
inserter
insert_iterator
front_inserter
back_inserter
move_sentinel (C++20)

common_iterator (C++20)
counted_iterator (C++20)
basic_const_iterator (C++23)
const_iterator (C++23)
const_sentinel (C++23)
make_const_iterator (C++23)
make_const_sentinel (C++23)

Stream iterators

istream_iterator
ostream_iterator

istreambuf_iterator
ostreambuf_iterator

Iterator customization points
ranges::iter_move (C++20)
ranges::iter_swap (C++20)

Iterator operations

advance
distance
prev (C++11)
next (C++11)

ranges::advance (C++20)
ranges::distance (C++20)
ranges::prev (C++20)
ranges::next (C++20)

Range access

begincbegin (C++11)(C++14)
rbegincrbegin (C++14)(C++14)

endcend (C++11)(C++14)
rendcrend (C++14)(C++14)

sizessize (C++17)(C++20)
empty (C++17)
data (C++17)

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Defined in header`<array>`
Defined in header`<deque>`
Defined in header`<flat_map>`
Defined in header`<flat_set>`
Defined in header`<forward_list>`
Defined in header`<inplace_vector>`
Defined in header`<iterator>`
Defined in header`<list>`
Defined in header`<map>`
Defined in header`<regex>`
Defined in header`<set>`
Defined in header`<span>`
Defined in header`<string>`
Defined in header`<string_view>`
Defined in header`<unordered_map>`
Defined in header`<unordered_set>`
Defined in header`<vector>`
template<class C> auto rbegin( C& c)-> decltype(c.rbegin());	(1)	(since C++14) (constexpr since C++17)
template<class C> auto rbegin(const C& c)-> decltype(c.rbegin());	(2)	(since C++14) (constexpr since C++17)
template<class T,std::size_t N> std::reverse_iterator<T*> rbegin( T(&array)[N]);	(3)	(since C++14) (constexpr since C++17)
template<class T> std::reverse_iterator<const T*> rbegin(std::initializer_list<T> il);	(4)	(since C++14) (constexpr since C++17)
template<class C> auto crbegin(const C& c)-> decltype(std::rbegin(c));	(5)	(since C++14) (constexpr since C++17)

Returns an iterator to the reverse-beginning of the given range.

1,2) Returnsc.rbegin(), which is typically an iterator to the reverse-beginning of the sequence represented byc.

1) IfC is a standardContainer, returns aC::reverse_iterator object.

2) IfC is a standardContainer, returns aC::const_reverse_iterator object.

3) Returns astd::reverse_iterator<T*> object to the reverse-beginning ofarray.

4) Returns astd::reverse_iterator<const T*> object to the reverse-beginning ofil.

5) Returnsstd::rbegin(c), withc always treated as const-qualified.

IfC is a standardContainer, returns aC::const_reverse_iterator object.

[edit]Parameters

c	-	a container or view with a`rbegin` member function
array	-	an array of arbitrary type
il	-	anstd::initializer_list

[edit]Return value

1,2)c.rbegin()

3)std::reverse_iterator<T*>(array+ N)

4)std::reverse_iterator<const T*>(il.end())

5)c.rbegin()

[edit]Exceptions

May throw implementation-defined exceptions.

[edit]Overloads

Custom overloads ofrbegin may be provided for classes and enumerations that do not expose a suitablerbegin() member function, yet can be iterated.

Overloads ofrbegin found byargument-dependent lookup can be used to customize the behavior ofstd::ranges::rbegin andstd::ranges::crbegin.

(since C++20)

[edit]Notes

The overload forstd::initializer_list is necessary because it does not have a member functionrbegin.

[edit]Example

Run this code

#include <iostream>#include <iterator>#include <vector> int main(){std::vector<int> v={3,1,4};auto vi= std::rbegin(v);// the type of “vi” is std::vector<int>::reverse_iteratorstd::cout<<"*vi = "<<*vi<<'\n'; *std::rbegin(v)=42;// OK: after assignment v[2] == 42//  *std::crbegin(v) = 13; // error: the location is read-only int a[]={-5,10,15};auto ai= std::rbegin(a);// the type of “ai” is std::reverse_iterator<int*>std::cout<<"*ai = "<<*ai<<'\n'; auto il={3,1,4};// the type of “it” below is std::reverse_iterator<int const*>:for(auto it= std::rbegin(il); it!=std::rend(il);++it)std::cout<<*it<<' ';std::cout<<'\n';}

Output:

*vi = 4*ai = 154 1 3

[edit]See also

begincbegin (C++11)(C++14)	returns an iterator to the beginning of a container or array (function template)[edit]
endcend (C++11)(C++14)	returns an iterator to the end of a container or array (function template)[edit]
rendcrend (C++14)	returns a reverse end iterator for a container or array (function template)[edit]
ranges::rbegin (C++20)	returns a reverse iterator to a range (customization point object)[edit]
ranges::crbegin (C++20)	returns a reverse iterator to a read-only range (customization point object)[edit]