<HTML> <!-- Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> <Head> <Title>Boost Graph Library: property_writer</Title> <BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" ALINK="#ff0000"> <IMG SRC="../../../boost.png" ALT="C++ Boost" width="277" height="86"> <BR Clear> <H1> <pre> property_writer<PropertyMap, OutputIterator, EventTag> </pre> </H1> This is an <a href="./EventVisitor.html">EventVisitor</a> that can be used to output the property of a vertex or edge at some event-point within an algorithm. <p> <tt>property_writer</tt> can be used with graph algorithms by wrapping it with the algorithm-specific adaptor, such as <a href="./bfs_visitor.html"><tt>bfs_visitor</tt></a> and <a href="./dfs_visitor.html"><tt>dfs_visitor</tt></a>. Also, this event visitor can be combined with other event visitors using <tt>std::pair</tt> to form an EventVisitorList. <h3>Example</h3> The following is an excerpt from <a href="../example/dave.cpp"><tt>examples/dave.cpp</tt></a>. <pre> std::ostream_iterator<int> cout_int(std::cout, " "); std::ostream_iterator<char> cout_char(std::cout, " "); boost::breadth_first_search (G, vertex(a, G), make_bfs_visitor( std::make_pair(write_property(name, cout_char, on_discover_vertex()), std::make_pair(write_property(distance.begin(), cout_int, on_discover_vertex()), std::make_pair(print_edge(name, std::cout, on_examine_edge()), print_endl(std::cout, on_finish_vertex() )))))); </pre> <h3>Model of</h3> <a href="./EventVisitor.html">EventVisitor</a> <H3>Where Defined</H3> <P> <a href="../../../boost/graph/visitors.hpp"> <TT>boost/graph/visitors.hpp</TT></a> <H3>Template Parameters</H3> <P> <TABLE border> <TR> <th>Parameter</th><th>Description</th><th>Default</th> </tr> <TR><TD><TT>PropertyMap</TT></TD> <TD> A <a href="../../property_map/doc/ReadablePropertyMap.html">ReadablePropertyMap</a> where the <tt>key_type</tt> is the vertex descriptor type or edge descriptor of the graph (depending on the kind of event tag) and the <tt>value_type</tt> of the property is convertible to the <tt>value_type</tt> of the <tt>OutputIterator</tt>. </TD> <TD> </TD> </TR> <TR><TD><TT>OutputIterator</TT></TD> <TD> The iterator type used to write out the property values, which must be a model of <a href="http://www.sgi.com/tech/stl/OutputIterator.html">OutputIterator</a>. </TD> <TD> </TD> </TR> <TR><TD><TT>EventTag</TT></TD> <TD> The tag to specify when the <tt>property_writer</tt> should be applied during the graph algorithm. </TD> <TD> </TD> </TR> </table> <H2>Associated Types</H2> <table border> <tr> <th>Type</th><th>Description</th> </tr> <tr> <td><tt>property_writer::event_filter</tt></td> <td> This will be the same type as the template parameter <tt>EventTag</tt>. </td> </tr> </table> <h3>Member Functions</h3> <p> <table border> <tr> <th>Member</th><th>Description</th> </tr> <tr> <td><tt> property_writer(PropertyMap pa, OutputIterator out); </tt></td> <td> Construct a property writer object with the property map <tt>pa</tt> and output iterator <tt>out</tt>. </td> </tr> <tr> <td><tt> template <class X, class Graph><br> void operator()(X x, const Graph& g); </tt></td> <td> This writes the property value for <tt>x</tt> to the output iterator.<br> <tt>*out++ = get(pa, x);</tt> </td> </tr> </table> <h3>Non-Member Functions</h3> <table border> <tr> <th>Function</th><th>Description</th> </tr> <tr><td><tt> template <class PropertyMap, class OutputIterator, class Tag><br> property_writer<PropertyMap, OutputIterator, Tag><br> write_property(PropertyMap pa, OutputIterator out, Tag); </tt></td><td> A convenient way to create a <tt>property_writer</tt>. </td></tr> </table> <h3>See Also</h3> <a href="./visitor_concepts.html">Visitor concepts</a> <p> The following are other event visitors: <a <a href="./distance_recorder.html"><tt>distance_recorder</tt></a>, <a href="./predecessor_recorder.html"><tt>predecessor_recorder</tt></a>, and <a href="./time_stamper.html"><tt>time_stamper</tt></a>. <br> <HR> <TABLE> <TR valign=top> <TD nowrap>Copyright © 2000-2001</TD><TD> <A HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</A>, Indiana University (<A HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)<br> <A HREF="http://www.boost.org/people/liequan_lee.htm">Lie-Quan Lee</A>, Indiana University (<A HREF="mailto:llee@cs.indiana.edu">llee@cs.indiana.edu</A>)<br> <A HREF="http://www.osl.iu.edu/~lums">Andrew Lumsdaine</A>, Indiana University (<A HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>) </TD></TR></TABLE> </BODY> </HTML> <!-- LocalWords: PropertyMap OutputIterator EventTag EventVisitor bfs dfs EventVisitorList --> <!-- LocalWords: cpp num dtime ftime int WritablePropertyMap map --> <!-- LocalWords: const Siek Univ Quan Lumsdaine -->