<!--
    Licensed to the Apache Software  Foundation (ASF) under one or more
    contributor  license agreements.  See  the NOTICE  file distributed
    with  this  work  for  additional information  regarding  copyright
    ownership.   The ASF  licenses this  file to  you under  the Apache
    License, Version  2.0 (the  License); you may  not use  this file
    except in  compliance with the License.   You may obtain  a copy of
    the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the  License is distributed on an  "AS IS" BASIS,
    WITHOUT  WARRANTIES OR CONDITIONS  OF ANY  KIND, either  express or
    implied.   See  the License  for  the  specific language  governing
    permissions and limitations under the License.

    Copyright 1999-2007 Rogue Wave Software, Inc.
-->

<HTML>
<HEAD>
<TITLE>adjacent_difference()</TITLE>
<LINK REL=StyleSheet HREF="../rw.css" TYPE="text/css" TITLE="Apache stdcxx Stylesheet"></HEAD>
<BODY BGCOLOR=#FFFFFF>
<A HREF="accumulate.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="adjacent-find.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>adjacent_difference()</H2>
<P><B>Library:</B>&nbsp;&nbsp;<A HREF="2-10.html">Numerics</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>A generalized numeric operation that outputs a sequence of the differences between each adjacent pair of elements in a range</P>
<A NAME="sec3"><H3>Synopsis</H3></A>

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

namespace std {
  template &lt;class InputIterator, class OutputIterator&gt;
  OutputIterator adjacent_difference(InputIterator start,
                                     InputIterator finish,
                                     OutputIterator result);
  template &lt;class InputIterator,
            class OutputIterator,
            class BinaryOperation&gt;
  OutputIterator adjacent_difference(InputIterator start,
                                     InputIterator finish,
                                     OutputIterator result,
                                     BinaryOperation bin_op);
}
</PRE>
<A NAME="sec4"><H3>Description</H3></A>
<P><SAMP>adjacent_difference()</SAMP> fills a sequence with the differences between successive elements in a container. The result is a sequence in which the first element is equal to the first element of the sequence being processed, and the remaining elements are equal to the calculated differences between adjacent elements. For instance, applying <SAMP>adjacent_difference()</SAMP> to {1,2,3,5} produces a result of {1,1,1,2}. </P>
<P>By default, subtraction is used to compute the difference, but you can supply any binary operator. The binary operator is then applied to adjacent elements. For example, by supplying the plus (+) operator, the result of applying <SAMP>adjacent_difference()</SAMP> to {1,2,3,5} is the sequence {1,3,5,8}.</P>
<A NAME="sec5"><H3>Complexity</H3></A>
<P>This algorithm performs exactly <SAMP>(finish-start) - 1</SAMP> applications of the default operation (<SAMP>-</SAMP>) or <SAMP>binary_op</SAMP>. </P>
<A NAME="sec6"><H3>Example</H3></A>

<UL><PRE>//
//  adj_diff.cpp
//

#include &lt;numeric&gt;       // for adjacent_difference
#include &lt;vector&gt;        // for vector
#include &lt;iostream&gt;      // for cout
#include &lt;functional&gt;    // for multiplies


int main ()
{
    // Typedefs for convenience.
    typedef std::vector&lt;long, std::allocator&lt;long&gt; &gt; Vector;

    typedef std::ostream_iterator &lt;Vector::value_type,
                                   char,
                                   std::char_traits&lt;char&gt; &gt;
            os_iter;

    // Initialize a Vector of ints from an array.
    const Vector::value_type arr [] = {
        1, 1, 2, 3, 5, 8, 13, 21, 34, 55
    };

    Vector v (arr + 0, arr + sizeof arr / sizeof *arr);

    // Two vectors initialized to all zeros
    // for storing results.
    Vector diffs (v.size ()),
           prods (v.size ());

    // Calculate difference(s) using
    // default operator (minus).
    std::adjacent_difference (v.begin (), v.end (),
                              diffs.begin ());

    // Calculate difference (s) using the times operator.
    std::adjacent_difference (v.begin (), v.end (),
                     prods.begin (),
                     std::multiplies&lt;Vector::value_type&gt; ());

    // Create an ostream_iterator object (for convenience).
    os_iter osit (std::cout, " ");

    // Output the results.
    std::cout &lt;&lt; "For the vector: " &lt;&lt; std::endl &lt;&lt; "     ";
    std::copy (v.begin (), v.end (), osit);

    std::cout &lt;&lt; std::endl &lt;&lt; std::endl;

    std::cout &lt;&lt; "The differences between adjacent elements"
              &lt;&lt; " are: " &lt;&lt; std::endl &lt;&lt; "    ";

    std::copy (diffs.begin (), diffs.end (), osit);
    std::cout &lt;&lt; std::endl &lt;&lt; std::endl;

    std::cout &lt;&lt; "The products of adjacent elements are: "
              &lt;&lt; std::endl &lt;&lt; "     ";

    std::copy (prods.begin (), prods.end (), osit);
    std::cout &lt;&lt; std::endl;

    return 0;
}
Program Output:
For the vector: 
     1 1 2 3 5 8 13 21 34 55 

The differences between adjacent elements are: 
    1 0 1 1 2 3 5 8 13 21 

The products of adjacent elements are: 
     1 1 2 6 15 40 104 273 714 1870 

</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 26.4.4</I></P>

<BR>
<HR>
<A HREF="accumulate.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="adjacent-find.html"><IMG SRC="images/bnext.gif" WIDTH=20 HEIGHT=21 ALT="Next file" BORDER=O></A>

<!-- Google Analytics tracking code -->
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
    _uacct = "UA-1775151-1";
    urchinTracker();
</script>
<!-- end of Google Analytics tracking code -->

</BODY>
</HTML>