std::reverse_copy

 

C++

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Technical Specifications

 

Algorithm library

Execution policies (C++17)
is_execution_policy	execution::seqexecution::parexecution::par_unseq	execution::sequenced_policyexecution::parallel_policyexecution::parallel_unsequenced_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_move (C++17)	uninitialized_copy_n (C++11) uninitialized_move_n (C++17)	uninitialized_fill	uninitialized_fill_n
Partitioning operations
is_partitioned (C++11) partition_point (C++11)	partition partition_copy (C++11)	stable_partition
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is_sorted (C++11) is_sorted_until (C++11)	sort stable_sort	partial_sort partial_sort_copy	nth_element
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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)	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 BidirIt, class OutputIt > OutputIt reverse_copy( BidirIt first, BidirIt last, OutputIt d_first );	(1)
template<class ExecutionPolicy, class BidirIt, class ForwardIt > ForwardIt reverse_copy( ExecutionPolicy&& policy, BidirIt first, BidirIt last, ForwardIt 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 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.

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
d_first	-	the beginning of the destination range
Type requirements
- BidirIt must meet the requirements of BidirectionalIterator.
- OutputIt must meet the requirements of OutputIterator.
- ForwardIt must meet the requirements of ForwardIterator.

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 and ExecutionPolicy is one of the three 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

template<class BidirIt, class OutputIt> OutputIt reverse_copy(BidirIt first, BidirIt last, OutputIt d_first){while(first != last){*(d_first++)=*(--last);}return d_first;}

Example

Run this code

#include <vector>#include <iostream>#include <algorithm>   int main(){std::vector<int> v({1,2,3});for(constauto& value : v){std::cout<< value <<" ";}std::cout<<'\n';   std::vector<int> destination(3); std::reverse_copy(std::begin(v), std::end(v), std::begin(destination));for(constauto& value : destination){std::cout<< value <<" ";}std::cout<<'\n';}

Output:

1 2 3 3 2 1

Complexity

Linear in the distance between first and last

See also

reverse

reverses the order of elements in a range (function template)