NAME¶

std::rend,std::crend - std::rend,std::crend

Synopsis¶

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

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 (since C++20)
customize the behavior of std::ranges::rend and std::ranges::crend.

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¶

end
cend returns an iterator to the end of a container or array
(C++11) (function template)
(C++14)
rbegin returns a reverse iterator to the beginning of a container or array
crbegin (function template)
(C++14)
begin
cbegin returns an iterator to the beginning of a container or array
(C++11) (function template)
(C++14)
ranges::rend returns a reverse end iterator to a range
(C++20) (customization point object)
ranges::crend returns a reverse end iterator to a read-only range
(C++20) (customization point object)