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It is provided "as is" without express or implied warranty. -- --><Head><Title>front_insert_iterator<FrontInsertionSequence></Title><!-- Generated by htmldoc --></HEAD><BODY TEXT="#000000" LINK="#006600" ALINK="#003300" VLINK="#7C7F87" BGCOLOR="#FFFFFF"><A HREF="/"><IMG SRC="/images/common/sgilogo_small.gif" ALT="SGI Logo" WIDTH="80" HEIGHT="72" BORDER="0"></A><P><!--end header--><BR Clear><H1>front_insert_iterator<FrontInsertionSequence></H1><Table CellPadding=0 CellSpacing=0 width=100%><TR><TD Align=left><Img src = "iterators.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD><TD Align=right><Img src = "type.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD></TR><TR><TD Align=left><Img src = "adaptors.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD><TD Align=right></TD></TR><TR><TD Align=left VAlign=top><b>Categories</b>: iterators, adaptors</TD><TD Align=right VAlign=top><b>Component type</b>: type</TD></TR></Table><h3>Description</h3><tt>Front_insert_iterator</tt> is an iterator adaptor that functions as an<A href="OutputIterator.html">Output Iterator</A>: assignment through a <tt>front_insert_iterator</tt> insertsan object before the first element of a <A href="FrontInsertionSequence.html">Front Insertion Sequence</A>. <A href="#1">[1]</A> <A href="#2">[2]</A><h3>Example</h3><pre><A href="List.html">list</A><int> L;L.push_front(3);front_insert_iterator<<A href="List.html">list</A><int> > ii(L);*ii++ = 0;*ii++ = 1;*ii++ = 2;<A href="copy.html">copy</A>(L.begin(), L.end(), <A href="ostream_iterator.html">ostream_iterator</A><int>(cout, " "));// The values that are printed are 2 1 0 3</pre><h3>Definition</h3>Defined in the standard header <A href="iterator">iterator</A>, and in the nonstandardbackward-compatibility header <A href="iterator.h">iterator.h</A>.<h3>Template parameters</h3><Table border><TR><TH>Parameter</TH><TH>Description</TH><TH>Default</TH></TR><TR><TD VAlign=top><tt>FrontInsertionSequence</tt></TD><TD VAlign=top>The type of <A href="FrontInsertionSequence.html">Front Insertion Sequence</A> into which values will be inserted.</TD><TD VAlign=top> </TD></tr></table><h3>Model of</h3><A href="OutputIterator.html">Output Iterator</A>. A front insert iterator's set of value types (asdefined in the <A href="OutputIterator.html">Output Iterator</A> requirements) consists ofa single type: <tt><A href="FrontInsertionSequence.html">FrontInsertionSequence</A>::value_type</tt>.<h3>Type requirements</h3>The template parameter <tt>FrontInsertionSequence</tt> must be a <A href="FrontInsertionSequence.html">Front Insertion Sequence</A>.<h3>Public base classes</h3>None.<h3>Members</h3><Table border><TR><TH>Member</TH><TH>Where defined</TH><TH>Description</TH></TR><TR><TD VAlign=top><tt>front_insert_iterator(FrontInsertionSequence&)</tt></TD><TD VAlign=top><tt>front_insert_iterator</tt></TD><TD VAlign=top>See below.</TD></TR><TR><TD VAlign=top><tt>front_insert_iterator(const front_insert_iterator&)</tt></TD><TD VAlign=top> <A href="trivial.html">Trivial Iterator</A></TD><TD VAlign=top>The copy constructor</TD></TR><TR><TD VAlign=top><pre>front_insert_iterator& operator=(const front_insert_iterator&)</pre></TD><TD VAlign=top> <A href="trivial.html">Trivial Iterator</A></TD><TD VAlign=top>The assignment operator</TD></TR><TR><TD VAlign=top><tt>front_insert_iterator& operator*()</tt></TD><TD VAlign=top> <A href="OutputIterator.html">Output Iterator</A></TD><TD VAlign=top>Used to implement the <A href="OutputIterator.html">output iterator</A> expression <tt>*i = x</tt>. <A href="#3">[3]</A></TD></TR><TR><TD VAlign=top><pre>front_insert_iterator& operator=(const FrontInsertionSequence::value_type&)</pre></TD><TD VAlign=top> <A href="OutputIterator.html">Output Iterator</A></TD><TD VAlign=top>Used to implement the <A href="OutputIterator.html">output iterator</A> expression <tt>*i = x</tt>. <A href="#3">[3]</A></TD></TR><TR><TD VAlign=top><tt>front_insert_iterator& operator++()</tt></TD><TD VAlign=top> <A href="OutputIterator.html">Output Iterator</A></TD><TD VAlign=top>Preincrement.</TD></TR><TR><TD VAlign=top><tt>front_insert_iterator& operator++(int)</tt></TD><TD VAlign=top> <A href="OutputIterator.html">Output Iterator</A></TD><TD VAlign=top>Postincrement.</TD></TR><TR><TD VAlign=top><pre>output_iterator_tag iterator_category(const front_insert_iterator&)</pre></TD><TD VAlign=top> <A href="iterator_tags.html">iterator tags</A></TD><TD VAlign=top>Returns the iterator's category. This is a global function, not a member.</TD></TR><TR><TD VAlign=top><pre>template<class FrontInsertionSequence>front_insert_iterator<FrontInsertionSequence>front_inserter(FrontInsertionSequence& S)</pre></TD><TD VAlign=top><tt>front_insert_iterator</tt></TD><TD VAlign=top>See below.</TD></tr></table><h3>New members.</h3>These members are not defined in the <A href="OutputIterator.html">Output Iterator</A> requirements,but are specific to <tt>front_insert_iterator</tt>.<Table border><TR><TH>Member</TH><TH>Description</TH></TR><TR><TD VAlign=top><tt>front_insert_iterator(FrontInsertionSequence& S)</tt></TD><TD VAlign=top>Constructs a <tt>front_insert_iterator</tt> that inserts objects before the first element of <tt>S</tt>.</TD></TR><TR><TD VAlign=top><pre>template<class FrontInsertionSequence>front_insert_iterator<FrontInsertionSequence>front_inserter(FrontInsertionSequence& S);</pre></TD><TD VAlign=top>Equivalent to <tt>front_insert_iterator<FrontInsertionSequence>(S)</tt>. <A href="#4">[4]</A> This is a global function, not a member function.</TD></tr></table><h3>Notes</h3><P><A name="1">[1]</A>Note the difference between assignment through a<tt><A href="FrontInsertionSequence.html">FrontInsertionSequence</A>::iterator</tt> and assignment through an<tt>front_insert_iterator<<A href="FrontInsertionSequence.html">FrontInsertionSequence</A>></tt>. If <tt>i</tt> is a valid<tt><A href="FrontInsertionSequence.html">FrontInsertionSequence</A>::iterator</tt>, then it points to some particularelement in the <A href="FrontInsertionSequence.html">front insertion sequence</A>; the expression <tt>*i = t</tt> replaces that element with <tt>t</tt>, and does not change the total numberof elements in the sequence. If <tt>ii</tt> is a valid<tt>front_insert_iterator<<A href="FrontInsertionSequence.html">FrontInsertionSequence</A>></tt>, however, then the expression <tt>*ii = t</tt> is equivalent, for some <A href="FrontInsertionSequence.html">FrontInsertionSequence</A><tt>seq</tt>, to the expression <tt>seq.push_front(t)</tt>. That is, it does not overwriteany of <tt>seq</tt>'s elements and it does change <tt>seq</tt>'s size.<P><A name="2">[2]</A>Note the difference between a <tt>front_insert_iterator</tt> and an<tt><A href="insert_iterator.html">insert_iterator</A></tt>. It may seem that a <tt>front_insert_iterator</tt> isthe same as an <tt><A href="insert_iterator.html">insert_iterator</A></tt> constructed with an insertionpoint that is the beginning of a sequence. In fact, though, there isa very important difference: <b>every</b> assignment through a<tt>front_insert_iterator</tt> corresponds to an insertion before the firstelement of the sequence. If you are inserting elements at thebeginning of a sequence using an <tt>insert_iterator</tt>, then the elementswill appear in the order in which they were inserted. If, however,you are inserting elements at the beginning of a sequence using a<tt>front_insert_iterator</tt>, then the elements will appear in the reverseof the order in which they were inserted.<P><A name="3">[3]</A>Note how assignment through an <tt>front_insert_iterator</tt> is implemented.In general, unary <tt>operator*</tt> must be defined so that it returns aproxy object, where the proxy object defines <tt>operator=</tt> to performthe insert operation. In this case, for the sake of simplicity, theproxy object is the <tt>front_insert_iterator</tt> itself. That is, <tt>*i</tt> simplyreturns <tt>i</tt>, and <tt>*i = t</tt> is equivalent to <tt>i = t</tt>. You should not,however, rely on this behavior. It is an implementation detail,and it is not guaranteed to remain the same in future versions.<P><A name="4">[4]</A>This function exists solely for the sake of convenience:since it is a non-member function, the template parameters may beinferred and the type of the <tt>front_insert_iterator</tt> need not be declaredexplicitly. One easy way to reverse a range and insert itat the beginning of a <A href="FrontInsertionSequence.html">Front Insertion Sequence</A> <tt>S</tt>, for example, is<tt><A href="copy.html">copy</A>(first, last, front_inserter(S))</tt>.<h3>See also</h3><A href="insert_iterator.html">insert_iterator</A>, <A href="back_insert_iterator.html">back_insert_iterator</A>, <A href="OutputIterator.html">Output Iterator</A>,<A href="Sequence.html">Sequence</A>, <A href="FrontInsertionSequence.html">Front Insertion Sequence</A>, <A href="Iterators.html">Iterator overview</A><!-- start footer --><!-- Footer Begins --><STYLE TYPE="text/css"><!--TD.footer, TD.footer A{ font-family: Arial, helvetica, sans-serif; font-size: 8pt;}A.home {font-family: Arial, helvetica, sans-serif;}--></STYLE><P><A CLASS="home" HREF="index.html">STL Home</A><P><TABLE WIDTH="600" CELLPADDING="0" CELLPADDING="0" BORDER="0"> <TR> <TD ALIGN="RIGHT" CLASS="footer"><A HREF="/company_info/terms.html" TARGET="_top">terms of use</A> | <A HREF="/company_info/privacy.html" TARGET="_top">privacy policy</A></TD> <TD ALIGN="CENTER" CLASS="footer"> | </TD> <TD ALIGN="LEFT" CLASS="footer"><A HREF="/cgi-bin/feedback/" TARGET="_top">contact us</A></TD> </TR><TR> <TD ALIGN="RIGHT" CLASS="footer">Copyright © 1993-2003 Silicon Graphics, Inc. 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