Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  reverse  - Reverse 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.h>
  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;
   }

  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

WARNING

  If your compiler does not support default template parameters, then you
  need to always supply the Allocator template argument.  For instance, you
  will need to write :

  vector<int, allocator<int> >

  instead of :

  vector<int>

SEE ALSO

  reverse_copy, swap

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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