std::rbegin, std::crbegin - cppreference.com (original) (raw)
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| Defined in header <flat_map> | ||
| Defined in header <flat_set> | ||
| Defined in header <forward_list> | ||
| Defined in header <inplace_vector> | ||
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| Defined in header <string_view> | ||
| Defined in header <unordered_map> | ||
| Defined in header <unordered_set> | ||
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| template< class C > auto rbegin( C& c ) -> decltype(c.rbegin()); | (1) | (since C++14) (constexpr since C++17) |
| template< class C > auto rbegin( const C& c ) -> decltype(c.rbegin()); | (2) | (since C++14) (constexpr since C++17) |
| template< class T, std::size_t N > std::reverse_iterator<T*> rbegin( T (&array)[N] ); | (3) | (since C++14) (constexpr since C++17) |
| template< class T > std::reverse_iterator<const T*> rbegin( std::initializer_list<T> il ); | (4) | (since C++14) (constexpr since C++17) |
| template< class C > auto crbegin( const C& c ) -> decltype(std::rbegin(c)); | (5) | (since C++14) (constexpr since C++17) |
Returns an iterator to the reverse-beginning of the given range.
1,2) Returns c.rbegin(), which is typically an iterator to the reverse-beginning of the sequence represented by c.
If
Cis a standard Container, returns aC::reverse_iteratorobject.If
Cis a standard Container, returns aC::const_reverse_iteratorobject.Returns std::rbegin(c), with c always treated as const-qualified.
If C is a standard Container, returns a C::const_reverse_iterator object.
[edit] Parameters
| c | - | a container or view with a rbegin member function |
|---|---|---|
| array | - | an array of arbitrary type |
| il | - | an std::initializer_list |
[edit] Return value
1,2) c.rbegin()
- c.rbegin()
[edit] Exceptions
May throw implementation-defined exceptions.
[edit] Overloads
Custom overloads of rbegin may be provided for classes and enumerations that do not expose a suitable rbegin() member function, yet can be iterated.
[edit] Notes
The overload for std::initializer_list is necessary because it does not have a member function rbegin.
[edit] Example
#include #include #include int main() { std::vector v = {3, 1, 4}; auto vi = std::rbegin(v); // the type of “vi” is std::vector::reverse_iterator std::cout << "*vi = " << *vi << '\n'; *std::rbegin(v) = 42; // OK: after assignment v[2] == 42 // *std::crbegin(v) = 13; // error: the location is read-only int a[] = {-5, 10, 15}; auto ai = std::rbegin(a); // the type of “ai” is std::reverse_iterator<int*> std::cout << "*ai = " << *ai << '\n'; auto il = {3, 1, 4}; // the type of “it” below is std::reverse_iterator<int const*>: for (auto it = std::rbegin(il); it != std::rend(il); ++it) std::cout << *it << ' '; std::cout << '\n'; }
Output:
[edit] See also
| | returns an iterator to the beginning of a container or array (function template) [edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | returns an iterator to the end of a container or array (function template) [edit] | | | returns a reverse end iterator for a container or array (function template) [edit] | | | returns a reverse iterator to a range(customization point object)[edit] | | | returns a reverse iterator to a read-only range(customization point object)[edit] |