std::vector<T,Allocator>::rend, std::vector<T,Allocator>::crend - cppreference.com (original) (raw)

reverse_iterator rend(); (1) (noexcept since C++11) (constexpr since C++20)
const_reverse_iterator rend() const; (2) (noexcept since C++11) (constexpr since C++20)
const_reverse_iterator crend() const noexcept; (3) (since C++11) (constexpr since C++20)

Returns a reverse iterator past the last element of the reversed *this. It corresponds to the element preceding the first element of the non-reversed *this.

This returned iterator only acts as a sentinel. It is not guaranteed to be dereferenceable.

range-rbegin-rend.svg

[edit] Return value

Reverse iterator to the element following the last element.

[edit] Complexity

Constant.

Notes

libc++ backports crend() to C++98 mode.

[edit] Example

#include #include #include #include #include   int main() { std::vector nums{1, 2, 4, 8, 16}; std::vector<std::string> fruits{"orange", "apple", "raspberry"}; std::vector empty;   // Print vector. std::for_each(nums.rbegin(), nums.rend(), [](const int n) { std::cout << n << ' '; }); std::cout << '\n';   // Sums all integers in the vector 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 vector fruits, checking if there is any. if (!fruits.empty()) std::cout << "First fruit: " << *fruits.rbegin() << '\n';   if (empty.rbegin() == empty.rend()) std::cout << "vector 'empty' is indeed empty.\n"; }

Output:

16 8 4 2 1 Sum of nums: 31 First fruit: raspberry vector 'empty' is indeed empty.

[edit] See also

| | returns a reverse iterator to the beginning (public member function) [edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | returns a reverse end iterator for a container or array (function template) [edit] |