std::rotate_copy

 

C++

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Symbols index

External libraries

 

Algorithm library

Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
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)
Non-modifying sequence operations
all_ofany_ofnone_of (C++11)(C++11)(C++11) for_each for_each_n (C++17)	countcount_if mismatch equal adjacent_find	search search_n lexicographical_compare lexicographical_compare_three_way (C++20)	findfind_iffind_if_not (C++11) find_end find_first_of
Modifying sequence operations
copycopy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) shift_leftshift_right (C++20)(C++20) transform	fill fill_n generate generate_n swap iter_swap swap_ranges sample (C++17)	removeremove_if replacereplace_if reverse rotate unique random_shuffle (until C++17)	remove_copyremove_copy_if replace_copyreplace_copy_if reverse_copy rotate_copy unique_copy shuffle (C++11)
Partitioning operations
is_partitioned (C++11) partition_point (C++11)	partition partition_copy (C++11)	stable_partition
Sorting operations
is_sorted (C++11) is_sorted_until (C++11)	sort stable_sort	partial_sort partial_sort_copy	nth_element
Binary search operations
lower_bound	upper_bound	binary_search	equal_range
Set operations (on sorted ranges)
merge inplace_merge	set_difference set_intersection	set_symmetric_difference set_union	includes
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is_heap (C++11) is_heap_until (C++11)	make_heap sort_heap	push_heap pop_heap
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max max_element	min min_element	minmax (C++11) minmax_element (C++11)	clamp (C++17)
Permutations
is_permutation (C++11)	next_permutation	prev_permutation
Numeric operations
iota (C++11) inner_product adjacent_difference	accumulate reduce (C++17) transform_reduce (C++17)	transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)	partial_sum inclusive_scan (C++17) exclusive_scan (C++17)
Operations on uninitialized storage
uninitialized_copy uninitialized_move (C++17) uninitialized_fill	uninitialized_copy_n (C++11) uninitialized_move_n (C++17) uninitialized_fill_n	uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17)	destroy (C++17) destroy_n (C++17) destroy_at (C++17) construct_at (C++20)
C library
qsort	bsearch

 

Defined in header <algorithm>
	(1)
template< class ForwardIt, class OutputIt > OutputIt rotate_copy( ForwardIt first, ForwardIt n_first,                       ForwardIt last, OutputIt d_first );			(until C++20)
template< class ForwardIt, class OutputIt > constexpr OutputIt rotate_copy( ForwardIt first, ForwardIt n_first,                                 ForwardIt last, OutputIt d_first );			(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 [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.

The behavior is undefined if either [first, n_first) or [n_first, last) is not a valid range, or the source and destination ranges overlap.

2) Same as (1), but executed according to policy. This overload does not participate in overload resolution unless

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)

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
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.

Return value

Output iterator to the element past the last element copied.

Complexity

linear in the distance between first and last.

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.

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); }

Example

Run this code

#include <algorithm>
#include <vector>
#include <iostream>
#include <iterator>
 
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';
}

Output:

3 4 5 1 2 
1 2 3 4 5

See also

rotate	rotates the order of elements in a range (function template)
ranges::rotate_copy (C++20)	copies and rotate a range of elements (niebloid)