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

NAME

  random_shuffle  - Randomly shuffles elements of a collection.

SYNOPSIS

  #include <algorithm>

  template <class RandomAccessIterator>
  void random_shuffle (RandomAccessIterator first,
                       RandomAccessIterator last);

  template <class RandomAccessIterator,
           class RandomNumberGenerator>
  void random_shuffle (RandomAccessIterator first,
                       RandomAccessIterator last,
                       RandomNumberGenerator& rand);

DESCRIPTION

  The random_shuffle algorithm shuffles the elements in the range [first,
  last) with uniform distribution. random_shuffle can take a particular
  random number generating function object rand , where rand takes a positive
  argument n of distance type of the RandomAccessIterator and returns a
  randomly chosen value between 0 and n - 1.

COMPLEXITY

  In the random_shuffle algorithm, (last - first) -1 swaps are done.

EXAMPLE

  //
  // rndshufl.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 random_shuffle: " << endl << "     ";
    copy(v.begin(),v.end(),ostream_iterator<int,char>(cout," "));
    cout << endl << endl;
     //Mix them up with random_shuffle
     random_shuffle(v.begin(), v.end());
     //Print out the mixed up elements
    cout << "Elements after random_shuffle: " << endl << "     ";
    copy(v.begin(),v.end(),ostream_iterator<int,char>(cout," "));
    cout << endl;

    return 0;
   }

  Output :
  Elements before random_shuffle:
      1 2 3 4 5 6 7 8 9 10
  Elements after random_shuffle:
      7 9 10 3 2 5 4 8 1 6

WARNING

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

  vector<int, allocator<int> >

  instead of :

  vector<int>

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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