std::map<Key,T,Compare,Allocator>::rbegin, std::map<Key,T,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)

Diagnostics library

Memory management library

Metaprogramming library(C++11)

General utilities library

Containers library

Iterators library

Ranges library(C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library(C++17)

Concurrency support library(C++11)

Execution control library(C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

node-handle (C++17)

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

hive (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::map

Member functions

map::map map::~map               map::operator= map::get_allocator

Element access map::at map::operator[] Iterators map::beginmap::cbegin (C++11) map::endmap::cend (C++11) map::rbeginmap::crbegin (C++11)      map::rendmap::crend (C++11) Capacity map::size map::max_size map::empty Observers map::key_comp map::value_comp Modifiers map::clear map::insert map::erase map::swap map::extract (C++17) map::merge (C++17) map::insert_range (C++23) map::insert_or_assign (C++17) map::emplace (C++11) map::emplace_hint (C++11) map::try_emplace (C++17) Lookup map::count map::find map::contains (C++20) map::equal_range map::lower_bound map::upper_bound

Non-member functions

operator==operator<=> (C++20) std::swap(std::map) erase_if(std::map) (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) (constexpr since C++26)
const_reverse_iterator rbegin()const;	(2)	(noexcept since C++11) (constexpr since C++26)
const_reverse_iterator crbegin()constnoexcept;	(3)	(since C++11) (constexpr since C++26)

Returns a reverse iterator to the first element of the reversed *this. It corresponds to the last element of the non-reversed *this.

If *this is empty, the returned iterator is equal to rend().

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.

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

Example

Run this code

#include <iomanip>#include <iostream>#include <string_view>#include <map>   int main(){conststd::map<int, std::string_view> coins {{10, "dime"}, {100, "dollar"}, {50, "half dollar"}, {5, "nickel"}, {1, "penny"}, {25, "quarter"}};// initializer entries in name alphabetical order   std::cout<<"US coins in circulation, largest to smallest denomination:\n";for(auto it = coins.crbegin(); it != coins.crend();++it)std::cout<<std::setw(11)<< it->second <<" = ¢"<< it->first <<'\n';}

Output:

US coins in circulation, largest to smallest denomination: dollar = ¢100 half dollar = ¢50 quarter = ¢25 dime = ¢10 nickel = ¢5 penny = ¢1

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)