std::reverse_copy (3) - Linux Manuals

std::reverse_copy: std::reverse_copy


std::reverse_copy - std::reverse_copy


Defined in header <algorithm>
template< class BidirIt, class OutputIt > (until C++20)
OutputIt reverse_copy( BidirIt first, BidirIt last, OutputIt d_first );
template< class BidirIt, class OutputIt > (1) (since C++20)
constexpr OutputIt reverse_copy( BidirIt first, BidirIt last, OutputIt d_first );
template< class ExecutionPolicy, class BidirIt, class ForwardIt > (2) (since C++17)
ForwardIt reverse_copy( ExecutionPolicy&& policy, BidirIt first, BidirIt last, ForwardIt d_first );

1) Copies the elements from the range [first, last) to another range beginning at d_first in such a way that the elements in the new range are in reverse order.
Behaves as if by executing the assignment *(d_first + (last - first) - 1 - i) = *(first + i) once for each non-negative i < (last - first)
If the source and destination ranges (that is, [first, last) and [d_first, d_first+(last-first)) respectively) overlap, the behavior is undefined.
2) Same as (1), but executed according to policy. This overload does not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true


first, last - the range of elements to copy
d_first - the beginning of the destination range

Type requirements

BidirIt must meet the requirements of LegacyBidirectionalIterator.
OutputIt must meet the requirements of LegacyOutputIterator.
ForwardIt must meet the requirements of LegacyForwardIterator.

Return value

Output iterator to the element past the last element copied.


The overload with a template parameter named ExecutionPolicy reports errors as follows:

* If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard_policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
* If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation

See also the implementations in libstdc++ and libc++.

  template<class BidirIt, class OutputIt>
  OutputIt reverse_copy(BidirIt first, BidirIt last, OutputIt d_first)
      while (first != last) {
          *(d_first++) = *(--last);
      return d_first;


// Run this code

  #include <vector>
  #include <iostream>
  #include <algorithm>

  int main()
      std::vector<int> v({1,2,3});
      for (const auto& value : v) {
          std::cout << value << " ";
      std::cout << '\n';

      std::vector<int> destination(3);
      std::reverse_copy(std::begin(v), std::end(v), std::begin(destination));
      for (const auto& value : destination) {
          std::cout << value << " ";
      std::cout << '\n';


  1 2 3
  3 2 1


Linear in the distance between first and last

See also

        reverses the order of elements in a range
reverse (function template)