<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>Iterator Property Map Adaptor</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> <H2><A NAME="sec:iterator-property-map"></A> </h2> <PRE> iterator_property_map<<a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">RandomAccessIterator</a>, OffsetMap, T, R> </PRE> <P> This property map is an adaptor that converts any random access iterator into a <a href="./LvaluePropertyMap.html">Lvalue Property Map</a>. The <tt>OffsetMap</tt> type is responsible for converting key objects to integers that can be used as offsets with the random access iterator. <P> <h3>Example</h3> <pre> // print out the capacity and flow for all the edges in the graph template <class Graph, class CapacityPMap, class FlowPMap> void print_network(Graph& G, CapacityPMap capacity, FlowPMap flow) { typedef typename boost::graph_traits<Graph>::vertex_iterator Viter; typedef typename boost::graph_traits<Graph>::out_edge_iterator OutEdgeIter; typedef typename boost::graph_traits<Graph>::in_edge_iterator InEdgeIter; Viter ui, uiend; for (boost::tie(ui, uiend) = vertices(G); ui != uiend; ++ui) { OutEdgeIter out, out_end; std::cout << *ui << "\t"; for(boost::tie(out, out_end) = out_edges(*ui, G); out != out_end; ++out) std::cout << "--(" << get(capacity, *out) << ", " << get(flow, *out) << ")--> " << target(*out,G) << "\t"; std::cout << std::endl << "\t"; InEdgeIter in, in_end; for(boost::tie(in, in_end) = in_edges(*ui, G); in != in_end; ++in) std::cout << "<--(" << get(capacity, *in) << "," << get(flow, *in) << ")-- " << source(*in,G) << "\t"; std::cout << std::endl; } } int main(int, char*[]) { typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, boost::no_plugin, boost::plugin<boost::id_tag, std::size_t> > Graph; const int num_vertices = 9; Graph G(num_vertices); int capacity[] = { 10, 20, 20, 20, 40, 40, 20, 20, 20, 10 }; int flow[] = { 8, 12, 12, 12, 12, 12, 16, 16, 16, 8 }; // add edges to the graph, and assign each edge an ID number // to index into the property arrays add_edge(G, 0, 1, 0); // ... typedef boost::graph_traits<Graph>::edge_descriptor Edge; typedef boost::property_map<Graph, boost::id_tag>::type EdgeID_PMap; EdgeID_PMap edge_id = get(boost::edge_index(), G); boost::iterator_property_map<int*, EdgeID_PMap, int, int&> capacity_pa(capacity, edge_id), flow_pa(flow, edge_id); print_network(G, capacity_pa, flow_pa); return 0; } </pre> <H3>Where Defined</H3> <P> <a href="../../../boost/property_map/property_map.hpp"><TT>boost/property_map/property_map.hpp</TT></a> <p> <H3>Model Of</H3> <a href="./LvaluePropertyMap.html">Lvalue Property Map</a> <P> <H3>Template Parameters</H3> <P> <TABLE border> <TR> <th>Parameter</th><th>Description</th><th>Default</th> </tr> <TR> <TD><TT>Iterator</TT></TD> <TD>Must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access Iterator</a>.</TD> <TD> </td> </tr> <TR> <TD><TT>OffsetMap</TT></TD> <TD>Must be a model of <a href="./ReadablePropertyMap.html">Readable Property Map</a> and the value type must be convertible to the difference type of the iterator.</TD> <TD> </TD> </TR> <TR> <TD><TT>T</TT></TD> <TD>The value type of the iterator.</TD> <TD><TT>std::iterator_traits<RandomAccessIterator>::value_type</TT></TD> </TR> <TR> <TD><TT>R</TT></TD> <TD>The reference type of the iterator.</TD> <TD><TT>std::iterator_traits<RandomAccessIterator>::reference</TT></TD> </TR> </TABLE> <P> <H3>Members</H3> <P> In addition to the methods and functions required by <a href="./LvaluePropertyMap.html">Lvalue Property Map</a>, this class has the following members. <hr> <pre> property_traits<iterator_property_map>::value_type </pre> This is the same type as <TT>std::iterator_traits<Iterator>::value_type</TT>. <hr> <pre> iterator_property_map(Iterator i) </pre> Constructor. The OffsetMap is default constructed. <hr> <pre> iterator_property_map(Iterator i, OffsetMap m) </pre> Constructor. <hr> <pre> reference operator[](difference_type v) const </pre> The operator bracket for property access. The <TT>reference</TT> and <TT>difference_type</TT> types are from <TT>std::iterator_traits<Iterator></TT>. <hr> <h3>Non-Member functions</h3> <hr> <pre> template <class RAIter, class OffsetMap> iterator_property_map<RAIter, OffsetMap, typename std::iterator_traits<RAIter>::value_type, typename std::iterator_traits<RAIter>::reference > make_iterator_property_map(RAIter iter, OffsetMap omap) </pre> A function for conveniently creating an iterator map. <hr> <pre> template <class RAIter, class OffsetMap, class ValueType> iterator_property_map<RAIter, OffsetMap, typename std::iterator_traits<RAIter>::value_type, typename std::iterator_traits<RAIter>::reference > make_iterator_property_map(RAIter iter, OffsetMap omap, ValueType dummy_arg) </pre> Use this function instead of the 2-argument version if your compiler does not support partial specialization (like Visual C++). <hr> <br> <HR> <TABLE> <TR valign=top> <TD nowrap>Copyright © 2000-2002</TD><TD> <a HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</a>, Univ.of Notre Dame (<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>, Univ.of Notre Dame (<A HREF="mailto:llee1@osl.iu.edu">llee1@osl.iu.edu</A>)<br> <A HREF="http://www.osl.iu.edu/~lums">Andrew Lumsdaine</A>, Univ.of Notre Dame (<A HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>) </TD></TR></TABLE> </BODY> </HTML>