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                       Standard C++ Library
             Copyright 1998, Rogue Wave Software, Inc.


NAME
     reverse

      - Reverses the order of elements in a collection.



SYNOPSIS
     #include <algorithm>
     template <class BidirectionalIterator>
     void reverse (BidirectionalIterator first,
                  BidirectionalIterator last);



DESCRIPTION
     The algorithm reverse reverses the elements in a sequence so
     that the last element becomes the new first element, and the
     first element becomes the new last.  For  each  non-negative
     integer  i  <= (last - first)/2, reverse applies swap to all
     pairs of iterators first + I, (last - I) - 1.

     Because the  iterators  are  assumed  to  be  bidirectional,
     reverse does not return anything.



COMPLEXITY
     reverse performs exactly (last - first)/2 swaps.



EXAMPLE
     //
     // reverse.cpp
     //
      #include <algorithm>
      #include <vector>
      #include <iostream>
     using namespace std;
     int main()
      {
        //Initialize a vector with an array of ints
       int arr[10] = {1,2,3,4,5,6,7,8,9,10};
       vector<int> v(arr, arr+10);

        //Print out elements in original (sorted) order
       cout << "Elements before reverse: " << endl << "     ";
       copy(v.begin(),v.end(),
            ostream_iterator<int,char>(cout," "));
       cout << endl << endl;

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

        //Print out the reversed elements
       cout << "Elements after reverse: " << endl << "     ";

       copy(v.begin(),v.end(),
            ostream_iterator<int,char>(cout," "));
       cout << 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



WARNINGS
     If your compiler does not support default  template  parame-
     ters,  then you always need to supply the Allocator template
     argument. For instance, you need to write:

     vector<int, allocator<int> >

     instead of:

     vector<int>

     If your compiler does not support namespaces,  then  you  do
     not need the using declaration for std.



SEE ALSO
     reverse_copy, swap

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