std::rotate_copy - cppreference.com

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# std::rotate_copy

From cppreference.com
< cpp‎ | algorithm

Defined in header `<algorithm>` |  |
template< class ForwardIt, class OutputIt > OutputIt rotate_copy( ForwardIt first, ForwardIt n_first, ForwardIt 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 element `n_first` becomes the first element of the new range and `n_first - 1` becomes the last element.

### [edit] Parameters

first, last | - | the range of elements to copy
n_first | - | an iterator to an element in `[first, last)` that should appear at the beginning of the new range
d_first | - | beginning of the destination range
Type requirements
- `ForwardIt` must meet the requirements of `ForwardIterator`.
- `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 ForwardIt, class OutputIt>
    OutputIt rotate_copy(ForwardIt first, ForwardIt n_first,
                               ForwardIt last, OutputIt d_first)
    {
        d_first = std::copy(n_first, last, d_first);
        return std::copy(first, n_first, d_first);
    }

### [edit] Example

Run this code

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

    int main()
    {
        std::vector<int> src = {1, 2, 3, 4, 5};
        auto pivot = std::find(src.begin(), src.end(), 3);
        std::vector<int> dest(src.size());

        std::rotate_copy(src.begin(), pivot, src.end(), dest.begin());

        for (const auto &i : dest) {
            std::cout << i << ' ';
        }
        std::cout << '\n';
    }

Output:

    3 4 5 1 2

### [edit] Complexity

linear in the distance between `first` and `last`

### [edit] See also

rotate | rotates the order of elements in a range (function template) [edit]
std::experimental::parallel::rotate_copy (parallelism TS) | parallelized version of `std::rotate_copy` (function template) [edit]

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