std::list<T,Allocator>::rbegin, std::list<T,Allocator>::crbegin
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list::rbeginlist::crbegin
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reverse_iterator rbegin();
(1)
(noexcept since C++11) (constexpr since C++26)
const_reverse_iterator rbegin() const;
(2)
(noexcept since C++11) (constexpr since C++26)
const_reverse_iterator crbegin() const noexcept;
(3)
(since C++11) (constexpr since C++26)
Returns a reverse iterator to the first element of the reversed *this. It corresponds to the last element of the non-reversed *this.
If *this is empty, the returned iterator is equal to rend() .
Contents
[edit] Return value
Reverse iterator to the first element.
[edit] Complexity
Constant.
[edit] Notes
The underlying iterator of the returned reverse iterator is the end iterator. Hence the returned iterator is invalidated if and when the end iterator is invalidated.
libc++ backports crbegin() to C++98 mode.
[edit] Example
Run this code
#include <algorithm> #include <iostream> #include <numeric> #include <string> #include <list> int main() { std::list <int> nums{1, 2, 4, 8, 16}; std::list <std::string > fruits{"orange", "apple", "raspberry"}; std::list <char> empty; // Print list. std::for_each (nums.rbegin(), nums.rend(), [](const int n) { std::cout << n << ' '; }); std::cout << '\n'; // Sums all integers in the list nums (if any), printing only the result. std::cout << "Sum of nums: " << std::accumulate (nums.rbegin(), nums.rend(), 0) << '\n'; // Prints the first fruit in the list fruits, checking if there is any. if (!fruits.empty()) std::cout << "First fruit: " << *fruits.rbegin() << '\n'; if (empty.rbegin() == empty.rend()) std::cout << "list 'empty' is indeed empty.\n"; }
Output:
16 8 4 2 1 Sum of nums: 31 First fruit: raspberry list 'empty' is indeed empty.
[edit] See also
(C++14)
(function template) [edit]