std::rend, std::crend

From cppreference.com
< cpp‎ | iterator
Defined in header <iterator>
(1)
template< class C >
auto rend( C& c ) -> decltype(c.rend());
(since C++14)
(until C++17)
template< class C >
constexpr auto rend( C& c ) -> decltype(c.rend());
(since C++17)
(1)
template< class C >
auto rend( const C& c ) -> decltype(c.rend());
(since C++14)
(until C++17)
template< class C >
constexpr auto rend( const C& c ) -> decltype(c.rend());
(since C++17)
(2)
template< class T, size_t N >
reverse_iterator<T*> rend( T (&array)[N] );
(since C++14)
(until C++17)
template< class T, size_t N >
constexpr reverse_iterator<T*> rend( T (&array)[N] );
(since C++17)
(3)
template< class C >
auto crend( const C& c ) -> decltype(std::rend(c));
(since C++14)
(until C++17)
template< class C >
constexpr auto crend( const C& c ) -> decltype(std::rend(c));
(since C++17)

Returns an iterator to the reverse-end of the given container c or array array.

1) Returns a possibly const-qualified iterator to the reverse-end of the container c.
2) Returns std::reverse_iterator<T*> to the reverse-end of the array array.
3) Returns a const-qualified iterator to the reverse-end of the container c.

range-rbegin-rend.svg

Contents

[edit] Parameters

c - a container with a rend method
array - an array of arbitrary type

[edit] Return value

An iterator to the reverse-end of c or array

[edit] Notes

In addition to being included in <iterator>, std::rend is guaranteed to become available if any of the following headers are included: <array>, <deque>, <forward_list>, <list>, <map>, <regex>, <set>, <string>, <unordered_map>, <unordered_set>, and <vector>.

[edit] Specializations

Custom specializations of std::rend may be provided for classes that do not expose a suitable rend() member function, yet can be iterated. The following specializations are already provided by the standard library:

specializes std::rend
(function)

[edit] Example

#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>
 
int main()
{
    int a[] = {4, 6, -3, 9, 10};
    std::cout << "Array backwards: ";
    std::copy(std::rbegin(a), std::rend(a), std::ostream_iterator<int>(std::cout, " "));
 
    std::cout << "\nVector backwards: ";
    std::vector<int> v = {4, 6, -3, 9, 10};
    std::copy(std::rbegin(v), std::rend(v), std::ostream_iterator<int>(std::cout, " "));
}

Output:

Array backwards: 10 9 -3 6 4 
Vector backwards: 10 9 -3 6 4

[edit] See also

(C++11)(C++14)
returns an iterator to the end of a container or array
(function)
returns a reverse iterator to a container or array
(function)
(C++11)(C++14)
returns an iterator to the beginning of a container or array
(function)