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std::reverse_copy

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Defined in header <algorithm>
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template< class BidirIt, class OutputIt >
OutputIt reverse_copy( BidirIt first, BidirIt last, OutputIt d_first );
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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.

Contents

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.

Return value

Output iterator to the element past the last element copied.

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

#include <vector>
#include <iostream>
#include <algorithm>
 
int main()
{
    std::vector<int> v({1,2,3});
    std::for_each(std::begin(v), std::end(v),
                  [&](int value){ std::cout << value << " "; });
    std::cout << std::endl;
 
    std::vector<int> destiny(3);
    std::reverse_copy(std::begin(v), std::end(v), std::begin(destiny));
    std::for_each(std::begin(destiny), std::end(destiny),
                  [&](int value){ std::cout << value << " "; });
    std::cout << std::endl;
}

Output:

1 2 3 
3 2 1

Complexity

linear in the distance between first and last

See also

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