std:: rend, std:: crend

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rend crend
(C++14) (C++14)
(C++17) (C++20)
(C++17)
(C++17)
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 rend ( C & c ) - > decltype ( c. rend ( ) ) ;
(1) (since C++14)
(constexpr since C++17)
template < class C >
auto rend ( const C & c ) - > decltype ( c. rend ( ) ) ;
(2) (since C++14)
(constexpr since C++17)
template < class T, std:: size_t N >
std:: reverse_iterator < T * > rend ( T ( & array ) [ N ] ) ;
(3) (since C++14)
(constexpr since C++17)
template < class T >
std:: reverse_iterator < const T * > rend ( std:: initializer_list < T > il ) ;
(4) (since C++14)
(constexpr since C++17)
template < class C >
auto crend ( const C & c ) - > decltype ( std :: rend ( c ) ) ;
(5) (since C++14)
(constexpr since C++17)

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

1,2) Returns c. rend ( ) , which is typically an iterator one past the reverse-end of the sequence represented by c .
1) If C is a standard Container , returns a C::reverse_iterator object.
2) If C is a standard Container , returns a C::const_reverse_iterator object.
3) Returns an std:: reverse_iterator < T * > object to the reverse-end of array .
4) Returns an std:: reverse_iterator < const T * > object to the reverse-end of il .
5) Returns std:: end ( c ) , with c always treated as const-qualified.
If C is a standard Container , returns a C::const_reverse_iterator object.

range-rbegin-rend.svg

Parameters

c - a container or view with a rend member function
array - an array of arbitrary type
il - an std:: initializer_list

Return value

1,2) c. rend ( )
3) std:: reverse_iterator < T * > ( array )
4) std:: reverse_iterator < const T * > ( il. begin ( ) )
5) c. rend ( )

Exceptions

May throw implementation-defined exceptions.

Overloads

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

Overloads of rend found by argument-dependent lookup can be used to customize the behavior of std :: ranges:: rend and std::ranges::crend .

(since C++20)

Notes

The overload for std::initializer_list is necessary because it does not have a member function rend .

Example

Run this code 
#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
 
int main()
{
    int a[]{4, 6, -3, 9, 10};
    std::cout << "C-style array `a` backwards: ";
    std::copy(std::rbegin(a), std::rend(a), std::ostream_iterator<int>(std::cout, " "));
 
    auto il = {3, 1, 4};
    std::cout << "\nstd::initializer_list `il` backwards: ";
    std::copy(std::rbegin(il), std::rend(il), std::ostream_iterator<int>(std::cout, " "));
 
    std::vector<int> v{4, 6, -3, 9, 10};
    std::cout << "\nstd::vector `v` backwards: ";
    std::copy(std::rbegin(v), std::rend(v), std::ostream_iterator<int>(std::cout, " "));
    std::cout << '\n';
}

Output: 

C-style array `a` backwards: 10 9 -3 6 4
std::initializer_list `il` backwards: 4 1 3
std::vector `v` backwards: 10 9 -3 6 4

See also

(C++11) (C++14)
returns an iterator to the end of a container or array
(function template)
(C++14)
returns a reverse iterator to the beginning of a container or array
(function template)
(C++11) (C++14)
returns an iterator to the beginning of a container or array
(function template)
(C++20)
returns a reverse end iterator to a range
(customization point object)
(C++20)
returns a reverse end iterator to a read-only range
(customization point object)
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