< cpp‎ | algorithm
Algorithm library
Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
Non-modifying sequence operations
Batch operations
Search operations
(C++11)                (C++11)(C++11)

Modifying sequence operations
Copy operations
Swap operations
Transformation operations
Generation operations
Removing operations
Order-changing operations
(until C++17)(C++11)
Sampling operations

Sorting and related operations
Partitioning operations
Sorting operations
Binary search operations
(on partitioned ranges)
Set operations (on sorted ranges)
Merge operations (on sorted ranges)
Heap operations
Minimum/maximum operations
Lexicographical comparison operations
Permutation operations
C library
Numeric operations
Operations on uninitialized memory
Defined in header <algorithm>
template< class ForwardIt, class OutputIt >

OutputIt rotate_copy( ForwardIt first, ForwardIt n_first,

                      ForwardIt last, OutputIt d_first );
(1) (constexpr since C++20)
template< class ExecutionPolicy,

          class ForwardIt1, class ForwardIt2 >
ForwardIt2 rotate_copy( ExecutionPolicy&& policy,
                        ForwardIt1 first, ForwardIt1 n_first,

                        ForwardIt1 last, ForwardIt2 d_first );
(2) (since C++17)
1) Copies the elements from the range [firstlast), 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.
2) Same as (1), but executed according to policy.
This overload participates in overload resolution only if

std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.

(until C++20)

std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true.

(since C++20)

If any of the following conditions is satisfied, the behavior is undefined:

  • [firstn_first) or [n_firstlast) is not a valid range.
  • The source and destination ranges overlap.


[edit] Parameters

first, last - the range of elements to copy
n_first - an iterator to an element in [firstlast) that should appear at the beginning of the new range
d_first - beginning of the destination range
policy - the execution policy to use. See execution policy for details.
Type requirements
ForwardIt, ForwardIt1, ForwardIt2 must meet the requirements of LegacyForwardIterator.
OutputIt must meet the requirements of LegacyOutputIterator.

[edit] Return value

Output iterator to the element past the last element copied.

[edit] Complexity

Exactly std::distance(first, last) assignments.

[edit] Exceptions

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.

[edit] Possible implementation

See also the implementations in libstdc++, libc++, and MSVC STL.

template<class ForwardIt, class OutputIt>
constexpr // since C++20
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

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
int main()
    std::vector<int> src{1, 2, 3, 4, 5};
    std::vector<int> dest(src.size());
    auto pivot = std::find(src.begin(), src.end(), 3);
    std::rotate_copy(src.begin(), pivot, src.end(), dest.begin());
    for (int i : dest)
        std::cout << i << ' ';
    std::cout << '\n';
    // copy the rotation result directly to the std::cout
    pivot = std::find(dest.begin(), dest.end(), 1);
    std::rotate_copy(dest.begin(), pivot, dest.end(),
                     std::ostream_iterator<int>(std::cout, " "));
    std::cout << '\n';


3 4 5 1 2
1 2 3 4 5

[edit] See also

rotates the order of elements in a range
(function template) [edit]
copies and rotate a range of elements