Defined in header
Call signature
template<std::bidirectional_iteratorI,std::sentinel_for<I>S,std::weakly_incrementableO>requiresstd::indirectly_copyable<I,O>constexprranges::reverse_copy_result<I,O>reverse_copy(Ifirst,Slast,Od_first); (1) (since C++20)template<ranges::bidirectional_rangeR,std::weakly_incrementableO>requiresstd::indirectly_copyable<ranges::iterator_t<R>,O>constexprranges::reverse_copy_result<ranges::borrowed_iterator_t<R>,O>reverse_copy(R&&r,Od_first); (2) (since C++20)template</*execution-policy*/Ep,std::random_access_iteratorI,std::sized_sentinel_for<I>S,std::random_access_iteratorO,std::sized_sentinel_for<O>OutS>requiresstd::indirectly_copyable<I,O>ranges::reverse_copy_truncated_result<I,O>reverse_copy(Ep&&policy,Ifirst,Slast,Od_first,OutSd_last); (3) (since C++26)template</*execution-policy*/Ep,/*sized-random-access-range*/R,/*sized-random-access-range*/OutR>requiresstd::indirectly_copyable<ranges::iterator_t<R>,ranges::iterator_t<OutR>>ranges::reverse_copy_truncated_result<ranges::borrowed_iterator_t<R>,ranges::borrowed_iterator_t<OutR>>reverse_copy(Ep&&policy,R&&r,OutR&&d_r); (4) (since C++26)Helper types
template<classI,classO>usingreverse_copy_result=ranges::in_out_result<I,O>; (5) (since C++20)template<classI,classO>usingreverse_copy_truncated_result=ranges::in_in_out_result<I,I,O>; (6) (since C++26)For the definition of /*execution-policy*/, see
; for the definition of /*sized-random-access-range*/, see
.
Copies elements from the source range [first, last) or r to the destination range in reverse order.
1,2) The destination range begins at d_first.
If the source and destination ranges overlap, the behavior is undefined.
3,4) Same as (1,2), but executed according to policy, and the destination range is [d_first, d_end) or d_r. If the destination range is exhausted before reaching the beginning of the source range, the remaining elements in the source range will not be copied.
If the source range and the following range overlap, the behavior is undefined:
3)[d_first, ranges::next(d_first,ranges::distance(first,last),d_last))
4)[d_r.begin(), ranges::next(d_r.begin(),ranges::distance(r),d_r.end()))
The function-like entities described on this page are
(informally known as niebloids), that is:
Explicit template argument lists cannot be specified when calling any of them.
None of them are visible to
.
When any of them are found by
as the name to the left of the function-call operator,
is inhibited.
Parameters
first, last - the iterator-sentinel pair defining the source
r - the source range d_first - the beginning of the destination range d_end - the sentinel of the destination range d_r - the destination range policy - the
to use Return value
1,2) A ranges::reverse_copy_result object where:
The data member
holds the past-the-end iterator of the source range.
The data member
holds the past-the-end iterator of the destination range.
3,4) A ranges::reverse_copy_truncated_result object where:
The data member
holds the past-the-end iterator of the source range.
The data member
holds an iterator to the last copied element in the source range, or the past-the-end iterator of the source range if no element is copied.
The data member
holds an iterator past the last assigned element in the destination range, or an iterator to the beginning of the destination range if no element is assigned.
Complexity
Given
N1 as ranges::distance(first,last) or ranges::distance(r),
N2 as ranges::distance(d_first,d_last) or ranges::distance(d_r):
1,2) Exactly N1 assignments.
3,4) Exactly min(N1,N2) assignments.
Exceptions
3,4) During the execution process:
If the temporary memory resources required for parallelization are not available,
is thrown.
If an uncaught exception is thrown while accessing objects via an algorithm argument, the behavior is determined by the execution policy (for
,
is invoked).
Notes
Implementations (e.g.
) may enable vectorization when the both iterator types model
and have the same value type, and the value type is
.
Possible implementation
See also the implementations in
and
.
structreverse_copy_fn{template<std::bidirectional_iteratorI,std::sentinel_for<I>S,std::weakly_incrementableO>requiresstd::indirectly_copyable<I,O>constexprranges::reverse_copy_result<I,O>operator()(Ifirst,Slast,Oresult)const{autoret=ranges::next(first,last);for(;last!=first;*result=*--last,++result);return{std::move(ret),std::move(result)};}template<ranges::bidirectional_rangeR,std::weakly_incrementableO>requiresstd::indirectly_copyable<ranges::iterator_t<R>,O>constexprranges::reverse_copy_result<ranges::borrowed_iterator_t<R>,O>operator()(R&&r,Oresult)const{return(*this)(ranges::begin(r),ranges::next(ranges::begin(r),ranges::end(r)),std::move(result));}};inlineconstexprreverse_copy_fnreverse_copy{};Example
Run this code
#include<algorithm>#include<iostream>#include<string>intmain(){std::stringx{"12345"},y(x.size(),' ');std::cout<<x<<" → ";std::ranges::reverse_copy(x.begin(),x.end(),y.begin());std::cout<<y<<" → ";std::ranges::reverse_copy(y,x.begin());std::cout<<x<<'\n';}Output:
12345 → 54321 → 12345 See also