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std::reverse_copy(3)	      C++ Standard Libary	  std::reverse_copy(3)

NAME
       std::reverse_copy - std::reverse_copy

Synopsis
	  Defined in header <algorithm>
	  template< class BidirIt, class OutputIt >
	  OutputIt   reverse_copy(   BidirIt  first,  BidirIt  last,  OutputIt
       (until C++20)
	  d_first );
	  template< class BidirIt, class OutputIt >
	  constexpr  OutputIt  reverse_copy(  BidirIt  first,  BidirIt	 last,
       (since C++20)
	  OutputIt d_first );						 (1)
	  template< class ExecutionPolicy, class BidirIt, class
	  ForwardIt >
									     (2)
       (since C++17)
	  ForwardIt reverse_copy( ExecutionPolicy&& policy,

	  BidirIt first, BidirIt last, ForwardIt d_first );

	  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 re-
       verse 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 unde-
       fined.
	  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>>
	  (until C++20)
	  std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>>
	  (since C++20)	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	LegacyBidirectionalIterator.
	  -
	  OutputIt must	meet the requirements of LegacyOutputIterator.
	  -
	  ForwardIt must meet the requirements of LegacyForwardIterator.

Return value
	  Output iterator to the element past the last element copied.

Complexity
	  Exactly last - first assignments.

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::termi-
       nate is called.
	      For  any	other ExecutionPolicy, the behavior is implementation-
       defined.
	    * If the algorithm fails to	 allocate  memory,  std::bad_alloc  is
       thrown.

Notes
	  Implementations  (e.g.  MSVC	STL) may enable	vectorization when the
       both iterator
	  types	satisfy	LegacyContiguousIterator and have the same value type,
       and the value
	  type is TriviallyCopyable.

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

	  template<class BidirIt, class	OutputIt>
	  constexpr // since C++20
	  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()
	{
	    auto print = [](std::vector<int> const& v) {
		for (const auto& value : v)
		    std::cout << value << ' ';
		std::cout << '\t';
	    };

	    std::vector<int> v({1,2,3});
	    print(v);

	    std::vector<int> destination(3);
	    std::reverse_copy(std::begin(v), std::end(v),  std::begin(destina-
       tion));
	    print(destination);

	    std::reverse_copy(std::rbegin(v),  std::rend(v), std::begin(desti-
       nation));
	    print(destination);
	}

Output:
	1 2 3	3 2 1	1 2 3

See also
	  reverse	       reverses	the order of elements in a range
			       (function template)
	  ranges::reverse_copy creates a copy of a range that is reversed
	  (C++20)	       (niebloid)

http://cppreference.com		  2022.07.31		  std::reverse_copy(3)

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