std::reverse_copy

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

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

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

1 2 3 
3 2 1

Complexity

Linear in the distance between first and last.

See also