# std::rbegin, std::crbegin

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< cpp‎ | iterator

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

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`.

### 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) (C++14) | specializes std::rbegin (function)

### 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

### See also

begin cbegin (C++11)(C++14) | returns an iterator to the beginning of a container or array (function template)
end cend (C++11)(C++14) | returns an iterator to the end of a container or array (function template)
rend crend (C++14) | returns a reverse end iterator for a container or array (function template)

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