std::deque::crend

const_reverse_iterator crend() const noexcept;

Returns a const_reverse_iterator pointing to the theoretical element preceding the first element in the container (which is considered itsreverse end).

const_reverse_iterator指向理论上存在于数组第一个元素之前位置的元素，这个元素被认为是反向的超尾元素。

Parameters

none

Return Value

A const_reverse_iterator to the reverse end of the sequence.

返回一个const_reverse_iterator指向序列的反向超尾元素。

Member type const_reverse_iterator is a reverse random access iterator type that points to
a const element (see deque member types).

迭代器属于随机迭代器。

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

// deque::crbegin/crend
#include <iostream>
#include <deque>

int main ()
{
  std::deque<int> mydeque = {1,2,3,4,5};

  std::cout << "mydeque backwards:";
  for (auto rit = mydeque.crbegin(); rit != mydeque.crend(); ++rit)
    std::cout << ' ' << *rit;
  std::cout << '\n';

  return 0;
}

Output:

mydeque backwards: 5 4 3 2 1

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
No contained elements are accessed by the call, but the iterator returned can be used to access them. Concurrently accessing or modifying different elements is safe.

容器的元素不会被访问，但是返回的迭代器可以被用来访问元素，同时访问以及修改其他元素是安全的。

Exception safety

No-throw guarantee: this member function never throws exceptions.

The copy construction or assignment of the returned iterator is also guaranteed to never throw.