std::rbegin,std::crbegin (3) - Linux Manuals

std::rbegin,std::crbegin: std::rbegin,std::crbegin

NAME

std::rbegin,std::crbegin - std::rbegin,std::crbegin

Synopsis

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

Returns an iterator to the reverse-beginning of the given container c or array array.
1) Returns a possibly const-qualified iterator to the reverse-beginning of the container c.
2) Returns std::reverse_iterator<T*> to the reverse-beginning of the array array.
3) Returns a const-qualified iterator to the reverse-beginning of the container c.
 range-rbegin-rend.svg

Parameters

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

Return value

An iterator to the reverse-beginning of c or array

Notes

In addition to being included in <iterator>, std::rbegin and std::crbegin are guaranteed to become available if any of the following headers are included: <array>, <deque>, <forward_list>, <list>, <map>, <regex>, <set>
, <span>
(since C++20), <string>
, <string_view>
(since C++17), <unordered_map>, <unordered_set>, and <vector>.

Overloads

Custom overloads of rbegin may be provided for classes that do not expose a suitable rbegin() member function, yet can be iterated. The following overload is already provided by the standard library:

rbegin(std::initializer_list) specializes std::rbegin
                              (function)
(C++14)

Example

// Run this code

  #include <iostream>
  #include <vector>
  #include <iterator>

  int main()
  {
      std::vector<int> v = { 3, 1, 4 };
      auto vi = std::rbegin(v);
      std::cout << *vi << '\n';

      int a[] = { -5, 10, 15 };
      auto ai = std::rbegin(a);
      std::cout << *ai << '\n';
  }

Output:

  4
  15