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std::reverse_copy

From cppreference.com
< cpp‎ | algorithm
 
 
 
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.

Contents

[edit] Parameters

first, last - the range of elements to copy
d_first - the beginning of the destination range
Type requirements
-
BidirIt must meet the requirements of BidirectionalIterator.
-
OutputIt must meet the requirements of OutputIterator.

[edit] Return value

Output iterator to the element past the last element copied.

[edit] 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;
}

[edit] 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';
}

Output:

1 2 3 
3 2 1

[edit] Complexity

Linear in the distance between first and last

[edit] See also

reverses the order elements in a range
(function template) [edit]