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 <H2>random_shuffle()</H2>
 <P><B>Library:</B>&nbsp;&nbsp;<A HREF="2-9.html">Algorithms</A></P>

 <PRE><HR><B><I>Function</I></B><HR></PRE>

 <UL>
 <LI><A HREF="#sec1">Local Index</A></LI>
 <LI><A HREF="#sec2">Summary</A></LI>
 <LI><A HREF="#sec3">Synopsis</A></LI>
 <LI><A HREF="#sec4">Description</A></LI>
 <LI><A HREF="#sec5">Complexity</A></LI>
 <LI><A HREF="#sec6">Example</A></LI>
 <LI><A HREF="#sec7">Standards Conformance</A></LI>
 </UL>
 <A NAME="sec1"><H3>Local Index</H3></A>
 No Entries
 <A NAME="sec2"><H3>Summary</H3></A>
 <P>Algorithm that randomly shuffles elements of a collection</P>
 <A NAME="sec3"><H3>Synopsis</H3></A>

 <PRE>#include &lt;algorithm&gt;

 namespace std {
   template &lt;class RandomAccessIterator&gt;
   void random_shuffle(RandomAccessIterator start,
                       RandomAccessIterator finish);

   template &lt;class RandomAccessIterator,
             class RandomNumberGenerator&gt;
   void random_shuffle(RandomAccessIterator start,
                       RandomAccessIterator finish,
                       RandomNumberGenerator&amp; rand);
 }
 </PRE>
 <A NAME="sec4"><H3>Description</H3></A>
 <P>The <SAMP>random_shuffle()</SAMP> algorithm shuffles the elements in the range <SAMP>[start, finish)</SAMP> with uniform distribution. <SAMP>random_shuffle()</SAMP> can take a particular random number generating function object <SAMP>rand</SAMP> (where <SAMP>rand</SAMP> takes a positive argument <SAMP>n</SAMP> of type convertible from <SAMP>std::iterator_traits&lt;RandomAccessIterator&gt;::difference_type</SAMP>) and returns a randomly chosen value between <SAMP>0 </SAMP>and<SAMP> n - 1</SAMP>. </P>
 <A NAME="sec5"><H3>Complexity</H3></A>
 <P>In the <SAMP>random_shuffle()</SAMP> algorithm, <SAMP>(finish - start) - 1 </SAMP>swaps are done.</P>
 <A NAME="sec6"><H3>Example</H3></A>

 <UL><PRE>//
 //  rndshufl.cpp
 //

 #include &lt;algorithm&gt;   // for random_shuffle
 #include &lt;iostream&gt;    // for cout, endl
 #include &lt;iterator&gt;    // for ostream_iterator
 #include &lt;string&gt;      // for string


 int main ()
 {
     // Create a string of doubles (unusual? maybe,
     // but why not...)
     typedef std::basic_string&lt;double,
                               std::char_traits&lt;double&gt;,
                               std::allocator&lt;double&gt; &gt;
             Bizarre;

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

     Bizarre b (a + 0, a + sizeof a / sizeof *a);

     typedef std::ostream_iterator&lt;double, char,
                                   std::char_traits&lt;char&gt; &gt;
             Iter;

     // Suppress decimal point in output.
     std::cout.precision (0);

     // Print out elements in original (sorted) order.
     std::cout &lt;&lt; "Elements before random_shuffle: \n     ";
     std::copy (b.begin (), b.end (), Iter (std::cout," "));

     // Mix them up with random_shuffle.
     std::random_shuffle (b.begin (), b.end ());

     // Print out the mixed up elements.
     std::cout &lt;&lt; "\n\nElements after random_shuffle: \n     ";
     std::copy (b.begin (), b.end (), Iter (std::cout, " "));
     std::cout &lt;&lt; std::endl;

     return 0;
 }


 Program Output:
 </PRE></UL>
 <UL><PRE>Elements before random_shuffle:
      1 2 3 4 5 6 7 8 9 10

 Elements after random_shuffle:
      9 8 7 6 2 3 1 4 5 10
 </PRE></UL>
 <A NAME="sec7"><H3>Standards Conformance</H3></A>
 <P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 25.2.11</I></P>

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	<H2>random_shuffle()</H2>
	<P><B>Library:</B>  <A HREF="2-9.html">Algorithms</A></P>

	<PRE><HR><B><I>Function</I></B><HR></PRE>

	<UL>
	<LI><A HREF="#sec1">Local Index</A></LI>
	<LI><A HREF="#sec2">Summary</A></LI>
	<LI><A HREF="#sec3">Synopsis</A></LI>
	<LI><A HREF="#sec4">Description</A></LI>
	<LI><A HREF="#sec5">Complexity</A></LI>
	<LI><A HREF="#sec6">Example</A></LI>
	<LI><A HREF="#sec7">Standards Conformance</A></LI>
	</UL>
	<A NAME="sec1"><H3>Local Index</H3></A>
	No Entries
	<A NAME="sec2"><H3>Summary</H3></A>
	<P>Algorithm that randomly shuffles elements of a collection</P>
	<A NAME="sec3"><H3>Synopsis</H3></A>

	<PRE>#include <algorithm>

	namespace std {
	template <class RandomAccessIterator>
	void random_shuffle(RandomAccessIterator start,
	RandomAccessIterator finish);

	template <class RandomAccessIterator,
	class RandomNumberGenerator>
	void random_shuffle(RandomAccessIterator start,
	RandomAccessIterator finish,
	RandomNumberGenerator& rand);
	}
	</PRE>
	<A NAME="sec4"><H3>Description</H3></A>
	<P>The <SAMP>random_shuffle()</SAMP> algorithm shuffles the elements in the range <SAMP>[start, finish)</SAMP> with uniform distribution. <SAMP>random_shuffle()</SAMP> can take a particular random number generating function object <SAMP>rand</SAMP> (where <SAMP>rand</SAMP> takes a positive argument <SAMP>n</SAMP> of type convertible from <SAMP>std::iterator_traits<RandomAccessIterator>::difference_type</SAMP>) and returns a randomly chosen value between <SAMP>0 </SAMP>and<SAMP> n - 1</SAMP>. </P>
	<A NAME="sec5"><H3>Complexity</H3></A>
	<P>In the <SAMP>random_shuffle()</SAMP> algorithm, <SAMP>(finish - start) - 1 </SAMP>swaps are done.</P>
	<A NAME="sec6"><H3>Example</H3></A>

	<UL><PRE>//
	// rndshufl.cpp
	//

	#include <algorithm> // for random_shuffle
	#include <iostream> // for cout, endl
	#include <iterator> // for ostream_iterator
	#include <string> // for string



	int main ()
	{
	// Create a string of doubles (unusual? maybe,
	// but why not...)
	typedef std::basic_string<double,
	std::char_traits<double>,
	std::allocator<double> >
	Bizarre;

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

	Bizarre b (a + 0, a + sizeof a / sizeof *a);

	typedef std::ostream_iterator<double, char,
	std::char_traits<char> >
	Iter;

	// Suppress decimal point in output.
	std::cout.precision (0);

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

	// Mix them up with random_shuffle.
	std::random_shuffle (b.begin (), b.end ());

	// Print out the mixed up elements.
	std::cout << "\n\nElements after random_shuffle: \n ";
	std::copy (b.begin (), b.end (), Iter (std::cout, " "));
	std::cout << std::endl;

	return 0;
	}


	Program Output:
	</PRE></UL>
	<UL><PRE>Elements before random_shuffle:
	1 2 3 4 5 6 7 8 9 10

	Elements after random_shuffle:
	9 8 7 6 2 3 1 4 5 10
	</PRE></UL>
	<A NAME="sec7"><H3>Standards Conformance</H3></A>
	<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 25.2.11</I></P>

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