std::rbegin, std::crbegin
From cppreference.com
Defined in header <array>
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Defined in header <deque>
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Defined in header <flat_map>
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Defined in header <flat_set>
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Defined in header <forward_list>
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Defined in header <inplace_vector>
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Defined in header <iterator>
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Defined in header <list>
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Defined in header <map>
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Defined in header <regex>
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Defined in header <set>
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Defined in header <span>
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Defined in header <string>
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Defined in header <string_view>
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Defined in header <unordered_map>
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Defined in header <unordered_set>
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Defined in header <vector>
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template
<
class C >
auto rbegin( C& c ) - > decltype(c.rbegin ( ) ) ; |
(1) | (since C++14) (constexpr since C++17) |
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template
<
class C >
auto rbegin( const C& c ) - > decltype(c.rbegin ( ) ) ; |
(2) | (since C++14) (constexpr since C++17) |
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template
<
class T, std::size_t N >
std::reverse_iterator <T* > rbegin( T ( &array) [N] ) ; |
(3) | (since C++14) (constexpr since C++17) |
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template
<
class T >
std::reverse_iterator < const T* > rbegin( std::initializer_list <T> il ) ; |
(4) | (since C++14) (constexpr since C++17) |
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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
5) Returns std::rbegin(c), with c
Parameters
| c | - | a container or view with a rbegin member function
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| array | - | an array of arbitrary type |
| il | - | an std::initializer_list |
Return value
1,2) c.rbegin()
3)
std::reverse_iterator
<T*
>
(array + N)
4)
std::reverse_iterator
<
const T*
>
(il.end
(
)
)
5) c.rbegin()
Exceptions
May throw implementation-defined exceptions.
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.
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Overloads of |
(since C++20) |
Notes
The overload for std::initializer_list is necessary because it does not have a member function rbegin.
Example
Run this code
#include <iostream> #include <iterator> #include <vector> int main() { std::vector<int> v = {3, 1, 4}; auto vi = std::rbegin(v); // the type of “vi” is std::vector<int>::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:
*vi = 4 *ai = 15 4 1 3
See also
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(C++11)(C++14)
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returns an iterator to the beginning of a container or array (function template) |
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(C++11)(C++14)
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returns an iterator to the end of a container or array (function template) |
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(C++14)
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returns a reverse end iterator for a container or array (function template) |
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(C++20)
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returns a reverse iterator to a range (customization point object) |
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(C++20)
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returns a reverse iterator to a read-only range (customization point object) |