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/C++std::map<Key,T,Compare,Allocator>::rend, std::map<Key,T,Compare,Allocator>::crend
| (1) | ||
reverse_iterator rend(); | (until C++11) | |
reverse_iterator rend() noexcept; | (since C++11) | |
| (2) | ||
const_reverse_iterator rend() const; | (until C++11) | |
const_reverse_iterator rend() const noexcept; | (since C++11) | |
const_reverse_iterator crend() const noexcept; | (3) | (since C++11) |
Returns a reverse iterator to the element following the last element of the reversed map. It corresponds to the element preceding the first element of the non-reversed map. This element acts as a placeholder, attempting to access it results in undefined behavior.
Parameters
(none).
Return value
Reverse iterator to the element following the last element.
Complexity
Constant.
Example
#include <chrono>
#include <iomanip>
#include <iostream>
#include <map>
#include <string_view>
using namespace std::chrono;
// until C++20 chrono operator<< ready
std::ostream& operator<<(std::ostream& os, const year_month_day& ymd)
{
return os << std::setfill('0') << static_cast<int>(ymd.year()) << '/'
<< std::setw(2) << static_cast<unsigned>(ymd.month()) << '/'
<< std::setw(2) << static_cast<unsigned>(ymd.day());
}
int main()
{
const std::map<year_month_day, int> messages
{
{ February/17/2023 , 10 },
{ February/17/2023 , 20 },
{ February/16/2022 , 30 },
{ October/22/2022 , 40 },
{ June/14/2022 , 50 },
{ November/23/2021 , 60 },
{ December/10/2022 , 55 },
{ December/12/2021 , 45 },
{ April/1/2020 , 42 },
{ April/1/2020 , 24 },
};
std::cout << "Messages received, reverse date order:\n";
for (auto it = messages.crbegin(); it != messages.crend(); ++it)
std::cout << it->first << " : " << it->second << '\n';
}Possible output:
Messages received, reverse date order: 2023/02/17 : 10 2022/12/10 : 55 2022/10/22 : 40 2022/06/14 : 50 2022/02/16 : 30 2021/12/12 : 45 2021/11/23 : 60 2020/04/01 : 42
See also
|
(C++11) | returns a reverse iterator to the beginning (public member function) |
|
(C++14) | returns a reverse end iterator for a container or array (function template) |
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