reverse_copy()

Library:  Algorithms

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An algorithm that reverses the order of elements in a sequence while copying them to a new sequence

#include <algorithm>

namespace std {
  template <class BidirectionalIterator, class OutputIterator>
  OutputIterator reverse_copy(BidirectionalIterator start,
                              BidirectionalIterator finish,
                              OutputIterator result);
}

The reverse_copy() algorithm copies the range [start, finish) to the range [result, result + (finish - start)) such that for any nonnegative integer i < (finish - start), the following assignment takes place:

*(result + (finish - start) - i) = *(start + i)

reverse_copy() returns result + (finish - start). The ranges [start, finish) and [result, result + (finish - start)) must not overlap.

reverse_copy() performs exactly (finish - start) assignments.

//
//  reverse.cpp
//

#include <algorithm>   // for reverse, reverse_copy
#include <vector>      // for vector
#include <iostream>    // for cout, endl
#include <iterator>    // for ostream_iterator



int main ()
{
    typedef std::vector<int, std::allocator<int> > Vector;
    typedef std::ostream_iterator<int, char,
                                  std::char_traits<char> >
            Iter;

    // Initialize a vector with an array of integers.
    const Vector::value_type a[] = { 1, 2, 3, 4, 5, 
                                     6, 7, 8, 9, 10 };

    Vector v (a + 0, a + sizeof a / sizeof *a);

    // Print out elements in original (sorted) order.
    std::cout << "Elements before reverse: \n     ";
    std::copy (v.begin (), v.end (), Iter (std::cout, " "));

    // Reverse the ordering.
    std::reverse (v.begin (), v.end ());

    // Print out the reversed elements.
    std::cout << "\n\nElements after reverse: \n     ";
    std::copy (v.begin (), v.end (), Iter (std::cout, " "));

    std::cout << "\n\nA reverse_copy to cout: \n     ";
    std::reverse_copy (v.begin (), v.end (), 
                       Iter (std::cout, " "));
    std::cout << std::endl;

    return 0;
}


Program Output:

Elements before reverse: 
     1 2 3 4 5 6 7 8 9 10 

Elements after reverse: 
     10 9 8 7 6 5 4 3 2 1 

A reverse_copy to cout: 
     1 2 3 4 5 6 7 8 9 10 

reverse()

ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 25.2.9