std::reverse_copy

 

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Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
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is_execution_policy (C++17)   execution::seqexecution::parexecution::par_unseqexecution::unseq (C++17)    (C++17)(C++17)(C++20)	execution::sequenced_policyexecution::parallel_policyexecution::parallel_unsequenced_policyexecution::parallel_unsequenced (C++17)(C++17)(C++17)(C++20)
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uninitialized_copy uninitialized_move (C++17)    uninitialized_fill uninitialized_copy_n (C++11) uninitialized_move_n (C++17) uninitialized_fill_n	destroy (C++17) destroy_n (C++17) destroy_at (C++17) construct_at (C++20)       uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17)

 

Defined in header <algorithm>
template< class BidirIt, class OutputIt > OutputIt reverse_copy( BidirIt first, BidirIt last, OutputIt d_first );

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.

Parameters

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

Return value

Output iterator to the element past the last element copied.

Possible implementation

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

Example

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';
}

Output:

1 2 3 
3 2 1

Complexity

Linear in the distance between first and last

See also

reverse	reverses the order of elements in a range (function template)
std::experimental::parallel::reverse_copy (parallelism TS)	parallelized version of std::reverse_copy (function template)