26 Algorithms library [algorithms]

26.7 Mutating sequence operations [alg.modifying.operations]

26.7.10 Reverse [alg.reverse]

template<class BidirectionalIterator> constexpr void reverse(BidirectionalIterator first, BidirectionalIterator last); template<class ExecutionPolicy, class BidirectionalIterator> void reverse(ExecutionPolicy&& exec, BidirectionalIterator first, BidirectionalIterator last); template<bidirectional_iterator I, sentinel_for<I> S> requires permutable<I> constexpr I ranges::reverse(I first, S last); template<bidirectional_range R> requires permutable<iterator_t<R>> constexpr borrowed_iterator_t<R> ranges::reverse(R&& r); template<execution-policy Ep, random_access_iterator I, sized_sentinel_for<I> S> requires permutable<I> I ranges::reverse(Ep&& exec, I first, S last); template<execution-policy Ep, sized-random-access-range R> requires permutable<iterator_t<R>> borrowed_iterator_t<R> ranges::reverse(Ep&& exec, R&& r);
Preconditions: For the overloads in namespace std, BidirectionalIterator meets the Cpp17ValueSwappable requirements ([swappable.requirements]).
Effects: For each non-negative integer i < (last - first) / 2, applies std​::​iter_swap, or ranges​::​​iter_swap for the overloads in namespace ranges, to all pairs of iterators first + i, (last - i) - 1.
Returns: last for the overloads in namespace ranges.
Complexity: Exactly (last - first)/2 swaps.
template<class BidirectionalIterator, class OutputIterator> constexpr OutputIterator reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result); template<class ExecutionPolicy, class BidirectionalIterator, class ForwardIterator> ForwardIterator reverse_copy(ExecutionPolicy&& exec, BidirectionalIterator first, BidirectionalIterator last, ForwardIterator result); template<bidirectional_iterator I, sentinel_for<I> S, weakly_incrementable O> requires indirectly_copyable<I, O> constexpr ranges::reverse_copy_result<I, O> ranges::reverse_copy(I first, S last, O result); template<bidirectional_range R, weakly_incrementable O> requires indirectly_copyable<iterator_t<R>, O> constexpr ranges::reverse_copy_result<borrowed_iterator_t<R>, O> ranges::reverse_copy(R&& r, O result);
Let N be last - first.
Preconditions: The ranges [first, last) and [result, result + N) do not overlap.
Effects: Copies the range [first, last) to the range [result, result + N) such that for every non-negative integer i < N the following assignment takes place: *(result + N - 1 - i) = *(first + i).
Returns:
  • result + N for the overloads in namespace std.
  • {last, result + N} for the overloads in namespace ranges.
Complexity: Exactly N assignments.
template<execution-policy Ep, random_access_iterator I, sized_sentinel_for<I> S, random_access_iterator O, sized_sentinel_for<O> OutS> requires indirectly_copyable<I, O> ranges::reverse_copy_truncated_result<I, O> ranges::reverse_copy(Ep&& exec, I first, S last, O result, OutS result_last); template<execution-policy Ep, sized-random-access-range R, sized-random-access-range OutR> requires indirectly_copyable<iterator_t<R>, iterator_t<OutR>> ranges::reverse_copy_truncated_result<borrowed_iterator_t<R>, borrowed_iterator_t<OutR>> ranges::reverse_copy(Ep&& exec, R&& r, OutR&& result_r);
Let N be min(last - first,  result_last - result), and let NEW_FIRST be first + (last - first) - N.
Preconditions: The ranges [first, last) and [result, result + N) do not overlap.
Effects: Copies the range [NEW_FIRST, last) to the range [result, result + N) such that for every non-negative integer the following assignment takes place: *(result + N - 1 - i) = *(NEW_FIRST + i).
Returns: {last, NEW_FIRST, result + N}.
Complexity: Exactly N assignments.