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It is provided "as is" without express or implied warranty. -- --><Head><Title>insert_iterator<Container></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>insert_iterator<Container></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>Insert_iterator</tt> is an iterator adaptor that functions as an<A href="OutputIterator.html">Output Iterator</A>: assignment through an <tt>insert_iterator</tt> insertsan object into a <A href="Container.html">Container</A>. Specifically, if <tt>ii</tt> is an<tt>insert_iterator</tt>, then <tt>ii</tt> keeps track of a <A href="Container.html">Container</A> <tt>c</tt>and an insertion point <tt>p</tt>; the expression <tt>*ii = x</tt> performsthe insertion <tt>c.insert(p, x)</tt>. <A href="#1">[1]</A><P>There are two different <A href="Container.html">Container</A> concepts that define thisexpression: <A href="Sequence.html">Sequence</A>, and <A href="SortedAssociativeContainer.html">Sorted Associative Container</A>.Both concepts define insertion into a container by means of<tt>c.insert(p, x)</tt>, but the semantics of this expression is very different in the two cases.<P>For a <A href="Sequence.html">Sequence</A> <tt>S</tt>, the expression <tt>S.insert(p, x)</tt> means toinsert the value <tt>x</tt> <i>immediately before</i> the iterator <tt>p</tt>. Thatis, the two-argument version of <tt>insert</tt> allows you to control thelocation at which the new element will be inserted. For a<A href="SortedAssociativeContainer.html">Sorted Associative Container</A>, however, no such control ispossible: the elements in a <A href="SortedAssociativeContainer.html">Sorted Associative Container</A> alwaysappear in ascending order of keys. <A href="SortedAssociativeContainer.html">Sorted Associative Containers</A>define the two-argument version of <tt>insert</tt> as an optimization. Thefirst argument is only a hint: it points to the location where the search will begin.<P>If you assign through an <tt>insert_iterator</tt> several times, then youwill be inserting several elements into the underlying container. Inthe case of a <A href="Sequence.html">Sequence</A>, they will appear at a particular locationin the underlying sequence, in the order in which they were inserted:one of the arguments to <tt>insert_iterator</tt>'s constructor is an iterator<tt>p</tt>, and the new range will be inserted immediately before <tt>p</tt>.<P>In the case of a <A href="SortedAssociativeContainer.html">Sorted Associative Container</A>, however, theiterator in the <tt>insert_iterator</tt>'s constructor is almost irrelevant.The new elements will not necessarily form a contiguous range; theywill appear in the appropriate location in the container, in ascendingorder by key. The order in which they are inserted only affects efficiency: inserting an already-sorted range into a<A href="SortedAssociativeContainer.html">Sorted Associative Container</A> is an <i>O(N</i>) operation.<h3>Example</h3>Insert a range of elements into a <tt><A href="List.html">list</A></tt>.<pre><A href="List.html">list</A><int> L;L.push_front(3);insert_iterator<<A href="List.html">list</A><int> > ii(L, L.begin());*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 0 1 2 3.</pre>Merge two sorted lists, inserting the resulting range into a <tt><A href="set.html">set</A></tt>. Note that a <tt><A href="set.html">set</A></tt> never contains duplicateelements.<pre>int main() { const int N = 6; int A1[N] = {1, 3, 5, 7, 9, 11}; int A2[N] = {1, 2, 3, 4, 5, 6}; <A href="set.html">set</A><int> result; <A href="merge.html">merge</A>(A1, A1 + N, A2, A2 + N, inserter(result, result.begin())); <A href="copy.html">copy</A>(result.begin(), result.end(), <A href="ostream_iterator.html">ostream_iterator</A><int>(cout, " ")); cout << endl; // The output is "1 2 3 4 5 6 7 9 11".}</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>Container</tt></TD><TD VAlign=top>The type of Container into which values will be inserted.</TD><TD VAlign=top> </TD></tr></table><h3>Model of</h3><A href="OutputIterator.html">Output Iterator</A>. An 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="Container.html">Container</A>::value_type</tt>.<h3>Type requirements</h3><UL><LI>The template parameter <tt>Container</tt> is a model of <A href="Container.html">Container</A>.<LI><tt>Container</tt> is variable-sized, as described in the <A href="Container.html">Container</A> requirements.<LI><tt>Container</tt> has a two-argument <tt>insert</tt> member function. Specifically, if <tt>c</tt> is an object of type <tt>Container</tt>, <tt>p</tt> is an object of type <tt>Container::iterator</tt> and <tt>v</tt> is an object of type <tt>Container::value_type</tt>, then <tt>c.insert(p, v)</tt> must be a valid expression.</UL><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>insert_iterator(Container&, Container::iterator)</tt></TD><TD VAlign=top><tt>insert_iterator</tt></TD><TD VAlign=top>See below.</TD></TR><TR><TD VAlign=top><tt>insert_iterator(const 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><tt>insert_iterator& operator=(const insert_iterator&)</tt></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>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="#2">[2]</A></TD></TR><TR><TD VAlign=top><tt>insert_iterator& operator=(const Container::value_type&)</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="#2">[2]</A></TD></TR><TR><TD VAlign=top><tt>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>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><tt>output_iterator_tag iterator_category(const insert_iterator&)</tt></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 Container, class Iter)insert_iterator<Container>inserter(Container& C, Iter i);</pre></TD><TD VAlign=top><tt>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>insert_iterator</tt>.<Table border><TR><TH>Member</TH><TH>Description</TH></TR><TR><TD VAlign=top><tt>insert_iterator(Container& C, Container::iterator i)</tt></TD><TD VAlign=top>Constructs an <tt>insert_iterator</tt> that inserts objects in <tt>C</tt>. If <tt>Container</tt> is a <A href="Sequence.html">Sequence</A>, then each object will be inserted immediately before the element pointed to by <tt>i</tt>. If <tt>C</tt> is a <A href="SortedAssociativeContainer.html">Sorted Associative Container</A>, then the first insertion will use <tt>i</tt> as a hint for beginning the search. The iterator <tt>i</tt> must be a dereferenceable or past-the-end iterator in <tt>C</tt>.</TD></TR><TR><TD VAlign=top><pre>template<class Container, class Iter)insert_iterator<Container>inserter(Container& C, Iter i);</pre></TD><TD VAlign=top>Equivalent to <tt>insert_iterator<Container>(C, i)</tt>. <A href="#2">[2]</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="Container.html">Container</A>::iterator</tt> and assignment through an<tt>insert_iterator<<A href="Container.html">Container</A>></tt>. If <tt>i</tt> is a valid<tt><A href="Sequence.html">Sequence</A>::iterator</tt>, then it points to some particularelement in the <A href="Container.html">container</A>; the expression <tt>*i = t</tt> replaces that element with <tt>t</tt>, and does not change the total numberof elements in the <A href="Container.html">container</A>. If <tt>ii</tt> is a valid<tt>insert_iterator<<A href="Container.html">container</A>></tt>, however, then the expression <tt>*ii = t</tt> is equivalent, for some <tt><A href="Container.html">container</A></tt><tt>c</tt> and some valid <tt><A href="Container.html">container</A>::iterator j</tt>, to the expression <tt>c.insert(j, t)</tt>. That is, it does not overwriteany of <tt>c</tt>'s elements and it does change <tt>c</tt>'s size.<P><A name="2">[2]</A>Note how assignment through an <tt>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>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="3">[3]</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>insert_iterator</tt> need not be declaredexplicitly. One easy way to reverse a range and insert itinto a <A href="Sequence.html">Sequence</A> <tt>S</tt>, for example, is<tt><A href="reverse_copy.html">reverse_copy</A>(first, last, inserter(S, S.begin()))</tt>.<h3>See also</h3><A href="front_insert_iterator.html">front_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="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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