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 <H2>push_heap()</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">See Also</A></LI>
 <LI><A HREF="#sec8">Standards Conformance</A></LI>
 </UL>
 <A NAME="sec1"><H3>Local Index</H3></A>
 No Entries
 <A NAME="sec2"><H3>Summary</H3></A>
 <P>An algorithm that places a new element into a heap</P>
 <A NAME="sec3"><H3>Synopsis</H3></A>

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

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

   template &lt;class RandomAccessIterator, class Compare&gt;
   void
   push_heap(RandomAccessIterator start,
             RandomAccessIterator finish, Compare comp);
 }
 </PRE>
 <A NAME="sec4"><H3>Description</H3></A>
 <P>A heap is a particular organization of elements in a range between two random access iterators <SAMP>[a, b)</SAMP>. Its two key properties are:</P>
 <OL>
 <LI><P CLASS="LIST"><SAMP>*a</SAMP> is the largest element in the range.</P></LI>
 <LI><P CLASS="LIST"><SAMP>*a</SAMP> may be removed by the <SAMP><A HREF="pop-heap.html">pop_heap()</A></SAMP> algorithm, or a new element may be added by the <SAMP>push_heap()</SAMP> algorithm, in <SAMP>O(logN)</SAMP> time.</P></LI>
 </OL>
 <P>These properties make heaps useful as priority queues.</P>
 <P>The first overload of the <SAMP>push_heap()</SAMP> algorithm uses <SAMP>operator&lt;()</SAMP> for comparison. The second overload uses the supplied binary predicate <SAMP>comp</SAMP>.</P>
 <P>The <SAMP>push_heap()</SAMP> algorithm is used to add a new element to the heap. First, a new element for the heap is added to the end of a range. The <SAMP>push_heap()</SAMP> algorithm assumes that the range <SAMP>[start, finish - 1)</SAMP> is a valid heap. Then it properly positions the element in the location <SAMP>finish - 1</SAMP> into its proper position in the heap, resulting in a heap over the range <SAMP>[start, finish)</SAMP>.</P>
 <A NAME="sec5"><H3>Complexity</H3></A>
 <P>For <SAMP>push_heap()</SAMP> at most <SAMP>log(finish - start)</SAMP> comparisons are performed.</P>
 <A NAME="sec6"><H3>Example</H3></A>

 <UL><PRE>//
 //  heap_ops.cpp
 //

 #include &lt;algorithm&gt;    // for copy, make_heap, pop_heap,
                         // and push_heap
 #include &lt;functional&gt;   // for less
 #include &lt;iostream&gt;     // for cout
 #include &lt;iterator&gt;     // for ostream_iterator
 #include &lt;vector&gt;       // for vector


 template &lt;class charT, class Traits, class T, class Allocator&gt;
 void print_vector (std::basic_ostream&lt;charT, Traits&gt; &amp;strm,
                    const std::vector&lt;T, Allocator&gt;   &amp;v)
 {
     std::copy (v.begin (), v.end (),
                std::ostream_iterator&lt;T, charT, Traits&gt;
                                     (strm, " "));

     strm &lt;&lt; std::endl;
 }


 int main ()
 {
     typedef std::vector&lt;int, std::allocator&lt;int&gt; &gt; Vector;

     const Vector::value_type d1[] = { 1, 2, 3, 4 };
     const Vector::value_type d2[] = { 1, 3, 2, 4 };

     // Set up two vectors.
     Vector v1 (d1 + 0, d1 + sizeof d1 / sizeof *d1);
     Vector v2 (d2 + 0, d2 + sizeof d2 / sizeof *d2);

     // Make heaps.
     std::make_heap (v1.begin (), v1.end ());
     std::make_heap (v2.begin (), v2.end (), std::less&lt;int&gt;());

     // v1 = (4, x, y, z)  and  v2 = (4, x, y, z)

     // Note that x, y and z represent the remaining values
     // in the container (other than 4).  The definition of
     // the heap and heap operations does not require any
     // particular ordering of these values.

     // Copy both vectors to cout.
     print_vector (std::cout, v1);
     print_vector (std::cout, v2);

     // Now let's pop.
     std::pop_heap (v1.begin (), v1.end ());
     std::pop_heap (v2.begin (), v2.end (), std::less&lt;int&gt;());

     print_vector (std::cout, v1);
     print_vector (std::cout, v2);

     // And push.
     std::push_heap (v1.begin (), v1.end ());
     std::push_heap (v2.begin (), v2.end (), std::less&lt;int&gt;());

     print_vector (std::cout, v1);
     print_vector (std::cout, v2);

     // Now sort those heaps.
     std::sort_heap (v1.begin (), v1.end ());
     std::sort_heap (v2.begin (), v2.end (), std::less&lt;int&gt;());

     print_vector (std::cout, v1);
     print_vector (std::cout, v2);

     return 0;
 }


 Program Output:
 </PRE></UL>
 <UL><PRE>4 2 3 1
 4 3 2 1
 3 2 1 4
 3 1 2 4
 4 3 1 2
 4 3 2 1
 1 2 3 4
 1 2 3 4
 </PRE></UL>
 <A NAME="sec7"><H3>See Also</H3></A>
 <P><SAMP><A HREF="make-heap.html">make_heap()</A></SAMP>, <SAMP><A HREF="pop-heap.html">pop_heap()</A></SAMP>, <SAMP><A HREF="sort-heap.html">sort_heap()</A></SAMP></P>
 <A NAME="sec8"><H3>Standards Conformance</H3></A>
 <P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 25.3.6.1</I></P>

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	<TITLE>push_heap()</TITLE>
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	<A HREF="ptr-fun.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="queue-h.html"><IMG SRC="images/bnext.gif" WIDTH=25 HEIGHT=21 ALT="Next file" BORDER=O></A><DIV CLASS="DOCUMENTNAME"><B>Apache C++ Standard Library Reference Guide</B></DIV>
	<H2>push_heap()</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">See Also</A></LI>
	<LI><A HREF="#sec8">Standards Conformance</A></LI>
	</UL>
	<A NAME="sec1"><H3>Local Index</H3></A>
	No Entries
	<A NAME="sec2"><H3>Summary</H3></A>
	<P>An algorithm that places a new element into a heap</P>
	<A NAME="sec3"><H3>Synopsis</H3></A>

	<PRE>#include <algorithm>

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

	template <class RandomAccessIterator, class Compare>
	void
	push_heap(RandomAccessIterator start,
	RandomAccessIterator finish, Compare comp);
	}
	</PRE>
	<A NAME="sec4"><H3>Description</H3></A>
	<P>A heap is a particular organization of elements in a range between two random access iterators <SAMP>[a, b)</SAMP>. Its two key properties are:</P>
	<OL>
	<LI><P CLASS="LIST"><SAMP>*a</SAMP> is the largest element in the range.</P></LI>
	<LI><P CLASS="LIST"><SAMP>*a</SAMP> may be removed by the <SAMP><A HREF="pop-heap.html">pop_heap()</A></SAMP> algorithm, or a new element may be added by the <SAMP>push_heap()</SAMP> algorithm, in <SAMP>O(logN)</SAMP> time.</P></LI>
	</OL>
	<P>These properties make heaps useful as priority queues.</P>
	<P>The first overload of the <SAMP>push_heap()</SAMP> algorithm uses <SAMP>operator<()</SAMP> for comparison. The second overload uses the supplied binary predicate <SAMP>comp</SAMP>.</P>
	<P>The <SAMP>push_heap()</SAMP> algorithm is used to add a new element to the heap. First, a new element for the heap is added to the end of a range. The <SAMP>push_heap()</SAMP> algorithm assumes that the range <SAMP>[start, finish - 1)</SAMP> is a valid heap. Then it properly positions the element in the location <SAMP>finish - 1</SAMP> into its proper position in the heap, resulting in a heap over the range <SAMP>[start, finish)</SAMP>.</P>
	<A NAME="sec5"><H3>Complexity</H3></A>
	<P>For <SAMP>push_heap()</SAMP> at most <SAMP>log(finish - start)</SAMP> comparisons are performed.</P>
	<A NAME="sec6"><H3>Example</H3></A>

	<UL><PRE>//
	// heap_ops.cpp
	//

	#include <algorithm> // for copy, make_heap, pop_heap,
	// and push_heap
	#include <functional> // for less
	#include <iostream> // for cout
	#include <iterator> // for ostream_iterator
	#include <vector> // for vector



	template <class charT, class Traits, class T, class Allocator>
	void print_vector (std::basic_ostream<charT, Traits> &strm,
	const std::vector<T, Allocator> &v)
	{
	std::copy (v.begin (), v.end (),
	std::ostream_iterator<T, charT, Traits>
	(strm, " "));

	strm << std::endl;
	}


	int main ()
	{
	typedef std::vector<int, std::allocator<int> > Vector;

	const Vector::value_type d1[] = { 1, 2, 3, 4 };
	const Vector::value_type d2[] = { 1, 3, 2, 4 };

	// Set up two vectors.
	Vector v1 (d1 + 0, d1 + sizeof d1 / sizeof *d1);
	Vector v2 (d2 + 0, d2 + sizeof d2 / sizeof *d2);

	// Make heaps.
	std::make_heap (v1.begin (), v1.end ());
	std::make_heap (v2.begin (), v2.end (), std::less<int>());

	// v1 = (4, x, y, z) and v2 = (4, x, y, z)

	// Note that x, y and z represent the remaining values
	// in the container (other than 4). The definition of
	// the heap and heap operations does not require any
	// particular ordering of these values.

	// Copy both vectors to cout.
	print_vector (std::cout, v1);
	print_vector (std::cout, v2);

	// Now let's pop.
	std::pop_heap (v1.begin (), v1.end ());
	std::pop_heap (v2.begin (), v2.end (), std::less<int>());

	print_vector (std::cout, v1);
	print_vector (std::cout, v2);

	// And push.
	std::push_heap (v1.begin (), v1.end ());
	std::push_heap (v2.begin (), v2.end (), std::less<int>());

	print_vector (std::cout, v1);
	print_vector (std::cout, v2);

	// Now sort those heaps.
	std::sort_heap (v1.begin (), v1.end ());
	std::sort_heap (v2.begin (), v2.end (), std::less<int>());

	print_vector (std::cout, v1);
	print_vector (std::cout, v2);

	return 0;
	}


	Program Output:
	</PRE></UL>
	<UL><PRE>4 2 3 1
	4 3 2 1
	3 2 1 4
	3 1 2 4
	4 3 1 2
	4 3 2 1
	1 2 3 4
	1 2 3 4
	</PRE></UL>
	<A NAME="sec7"><H3>See Also</H3></A>
	<P><SAMP><A HREF="make-heap.html">make_heap()</A></SAMP>, <SAMP><A HREF="pop-heap.html">pop_heap()</A></SAMP>, <SAMP><A HREF="sort-heap.html">sort_heap()</A></SAMP></P>
	<A NAME="sec8"><H3>Standards Conformance</H3></A>
	<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 25.3.6.1</I></P>

	<BR>
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