std::rotate_copy

 

C++

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Regular expressions library (C++11)

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Technical Specifications

 

Algorithm library

Execution policies (C++17)
is_execution_policy	sequentialparpar_vec	sequential_execution_policyparallel_execution_policyparallel_vector_execution_policy
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 lexicographical_compare	findfind_iffind_if_not (C++11) find_end find_first_of	adjacent_find search search_n
Modifying sequence operations
copycopy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) 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)
Operations on uninitialized storage
uninitialized_copy	uninitialized_copy_n	uninitialized_fill	uninitialized_fill_n
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
Heap operations
is_heap (C++11) is_heap_until (C++11)	make_heap sort_heap	push_heap pop_heap
Minimum/maximum operations
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)	partial_sum inclusive_scan (C++17) exclusive_scan (C++17)	transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
C library
qsort	bsearch

 

Defined in header <algorithm>
template< class ForwardIt, class OutputIt > OutputIt rotate_copy( ForwardIt first, ForwardIt n_first,                       ForwardIt last, OutputIt d_first );	(1)
template< class ExecutionPolicy, class ForwardIt, class OutputIt > OutputIt rotate_copy( ExecutionPolicy&& policy, ForwardIt first, ForwardIt n_first,                       ForwardIt last, OutputIt 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.

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

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 must meet the requirements of ForwardIterator.
- OutputIt must meet the requirements of OutputIterator.

Return value

Output iterator to the element past the last element copied.

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,

• if policy is std::parallel_vector_execution_policy, std::terminate is called
• if policy is std::sequential_execution_policy or std::parallel_execution_policy, the algorithm exits with an std::exception_list containing all uncaught exceptions. If there was only one uncaught exception, the algorithm may rethrow it without wrapping in std::exception_list. It is unspecified how much work the algorithm will perform before returning after the first exception was encountered.
• if policy is some other type, the behavior is implementation-defined

• If the algorithm fails to allocate memory (either for itself or to construct an std::exception_list when handling a user exception), std::bad_alloc is thrown.

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); }

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

Complexity

linear in the distance between first and last

See also

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