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<H2>ostream_iterator</H2>
<P><B>Library:</B>&nbsp;&nbsp;<A HREF="2-8.html">Iterators</A></P>

<PRE><HR><B><I>ostream_iterator</I></B> <IMG SRC="images/inherits.gif"> <B><I><A HREF="iterator.html">iterator</A></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">Interface</A></LI>
<LI><A HREF="#sec6">Member Types</A></LI>
<LI><A HREF="#sec7">Constructors</A></LI>
<LI><A HREF="#sec8">Operators</A></LI>
<LI><A HREF="#sec9">Example</A></LI>
<LI><A HREF="#sec10">See Also</A></LI>
<LI><A HREF="#sec11">Standards Conformance</A></LI>
</UL>
<A NAME="sec1"><H3>Local Index</H3></A>
<H4>Members</H4>
<UL><TABLE CELLPADDING=3>
<TR><TD VALIGN=top>
<A HREF="#idx1060">char_type</A><BR>
<A HREF="#idx1067">operator*()</A><BR>
</TD>
<TD VALIGN=top><A HREF="#idx1067">operator++()</A><BR>
<A HREF="#idx1066">operator=()</A><BR>
</TD>
<TD VALIGN=top><A HREF="#idx1063">ostream_iterator()</A><BR>
<A HREF="#idx1062">ostream_type</A><BR>
</TD>
<TD VALIGN=top><A HREF="#idx1061">traits_type</A><BR>
</TD></TR>
</TABLE></UL>

<A NAME="sec2"><H3>Summary</H3></A>
<P>Stream iterators allow for use of iterators with ostreams and istreams. They allow generic algorithms to be used directly on streams.</P>
<A NAME="sec3"><H3>Synopsis</H3></A>

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

namespace std {
  template &lt;class T, class charT, 
            class traits = char_traits&lt;charT&gt; &gt;
  class ostream_iterator;
}
</PRE>
<A NAME="sec4"><H3>Description</H3></A>
<P>Stream iterators use the standard iterator interface for input and output streams.</P>
<P>The class template <B><I>ostream_iterator</I></B> writes elements to an output stream. If you use the constructor that has a second argument, then that string is written after every element (the string must be null-terminated). Since an ostream iterator is an output iterator, it is not possible to dereference values through the iterator. You can only assign to it.</P>
<A NAME="sec5"><H3>Interface</H3></A>

<UL><PRE>namespace std {

  template &lt;class T, class charT = char, 
            class traits = char_traits&lt;charT&gt; &gt;
  class ostream_iterator:  
    public iterator&lt;output_iterator_tag,void,void,void,void&gt; 
  {
    public:
    typedef T value_type;
    typedef charT char_type;
    typedef traits traits_type;
    typedef basic_ostream&lt;charT,traits&gt; ostream_type;

    ostream_iterator(ostream_type&amp;);
    ostream_iterator(ostream_type&amp;, const char_type*); 
    ostream_iterator(const ostream_iterator&amp;);

    ostream_iterator&amp; operator=(const T&amp;);
    ostream_iterator&amp; operator*() const;
    ostream_iterator&amp; operator++();
    ostream_iterator  operator++(int);
  };
}
</PRE></UL>
<A NAME="sec6"><H3>Member Types</H3></A>

<A NAME="idx1060"></A><PRE><B>char_type</B>; </PRE>
<UL>
<P>Type of character the stream is built on.</P>
</UL>


<A NAME="idx1061"></A><PRE><B>traits_type</B>; </PRE>
<UL>
<P>Traits used to build the stream.</P>
</UL>


<A NAME="idx1062"></A><PRE><B>ostream_type</B>; </PRE>
<UL>
<P>Type of stream this iterator is constructed on.</P>
</UL>

<A NAME="sec7"><H3>Constructors</H3></A>

<A NAME="idx1063"></A><PRE><B>ostream_iterator</B> (ostream_type&amp; s);</PRE>
<UL>
<P>Constructs an <B><I>ostream_iterator</I></B> on the given stream.</P>
</UL>


<A NAME="idx1064"></A><PRE><B>ostream_iterator</B> (ostream_type&amp; s, 
                  const char_type* delimiter);</PRE>
<UL>
<P>Constructs an <B><I>ostream_iterator</I></B> on the given stream. The null terminated string <SAMP>delimiter</SAMP> is written to the stream after every element.</P>
</UL>


<A NAME="idx1065"></A><PRE><B>ostream_iterator</B> (const ostream_iterator&amp; x);</PRE>
<UL>
<P> Copy constructor.</P>
</UL>

<A NAME="sec8"><H3>Operators</H3></A>

<A NAME="idx1066"></A><PRE>const T&amp; <br><B>operator= </B>(const T&amp; value);</PRE>
<UL>
<P> Insert <SAMP>value</SAMP> into the associated output stream <SAMP>x</SAMP> by calling <SAMP>x &lt;&lt; value</SAMP>.</P>
</UL>


<A NAME="idx1067"></A><PRE>const T&amp; ostream_iterator&amp; 
<B>operator*</B> ();
ostream_iterator&amp;  
<B>operator++</B>();
ostream_iterator
<B>operator++ </B>(int);</PRE>
<UL>
<P>These operators do nothing. They simply allow the iterator to be used in common constructs.</P>
</UL>

<A NAME="sec9"><H3>Example</H3></A>

<UL><PRE> #include &lt;iterator&gt;
 #include &lt;numeric&gt;
 #include &lt;deque&gt;
 #include &lt;iostream&gt;
 using namespace std;

 int main ()
 {
   //
   // Initialize a vector using an array.
   //
   int arr[4] = { 3,4,7,8 };
   int total=0;
   deque&lt;int&gt; d(arr+0, arr+4);
   //
   // stream the whole vector and a sum to cout
   //
   copy(d.begin(),d.end()-1,
        <B>ostream_iterator</B>&lt;int,char&gt;(cout," + "));
   cout &lt;&lt; *(d.end()-1) &lt;&lt; " = " &lt;&lt;
        accumulate(d.begin(),d.end(),total) &lt;&lt; endl;
   return 0;
 }
</PRE></UL>
<A NAME="sec10"><H3>See Also</H3></A>
<P><B><I><A HREF="istream-iterator.html">istream_iterator</A></I></B>, <A HREF="iterators.html">Iterators</A></P>
<A NAME="sec11"><H3>Standards Conformance</H3></A>
<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 24.5.2</I></P>

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