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//=======================================================================
// Copyright 2001 Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee,
//
// 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)
//=======================================================================
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/adjacency_list.hpp>
using namespace boost;
template < typename Graph > void
generic_foo(Graph & g)
{
// Access descriptor types
typedef typename graph_traits < Graph >::vertex_descriptor Vertex;
typedef typename graph_traits < Graph >::edge_descriptor Edge;
// Access category types
typedef typename graph_traits < Graph >::directed_category Dir;
typedef typename graph_traits < Graph >::edge_parallel_category Par;
// Access iterator types...
// Access size types...
// Now do something useful...
}
template < typename Graph > void
generic_bar(Graph & g)
{
// Declare some vertex and edge descriptor variables
typename graph_traits < Graph >::vertex_descriptor u, v;
typename graph_traits < Graph >::edge_descriptor e1, e2;
// Set u and e1 to valid descriptors...
v = u; // Make v a handle to the same vertex as u.
e2 = e1; // Make e2 a handle to the same edge as e1.
assert(u == v); // Do u and v identify the same vertex? Yes
assert(!(u != v)); // Do u and v identify different vertices? No
assert(e1 == e2); // Do e1 and e2 identify the same edge? Yes
assert(!(e1 != e2)); // Do e1 and e2 identify different edges? No
}
// This version of foo gets called when g is directed
template < typename Graph > void
foo_dispatch(Graph & g, boost::directed_tag)
{
//...
}
// This version of foo gets called when g is undirected
template < typename Graph > void
foo_dispatch(Graph & g, boost::undirected_tag)
{
//...
}
template < typename Graph > void
foo(Graph & g)
{
typedef typename boost::graph_traits < Graph >::directed_category Cat;
foo_dispatch(g, Cat());
}
template < typename Digraph > void
foo(Digraph & digraph,
typename graph_traits < Digraph >::vertex_descriptor u,
typename graph_traits < Digraph >::vertex_descriptor v)
{
typedef typename graph_traits < Digraph >::edge_descriptor edge_t;
std::pair<edge_t, bool> e1, e2;
e1 = edge(u, v, digraph);
e2 = edge(v, u, digraph);
assert(e1.first != e2.first);
}
template < typename Undigraph > void
bar(Undigraph & undigraph,
typename graph_traits < Undigraph >::vertex_descriptor u,
typename graph_traits < Undigraph >::vertex_descriptor v)
{
typedef typename graph_traits < Undigraph >::edge_descriptor edge_t;
std::pair<edge_t, bool> e1, e2;
e1 = edge(u, v, undigraph);
e2 = edge(v, u, undigraph);
assert(e1.first == e2.first);
}
int
main()
{
boost::adjacency_list < vecS, vecS, directedS > g(2);
add_edge(0, 1, g);
add_edge(1, 0, g);
generic_foo(g);
generic_bar(g);
foo(g);
foo(g, vertex(0, g), vertex(1, g));
boost::adjacency_list < vecS, vecS, undirectedS > ug(2);
add_edge(0, 1, g);
bar(ug, vertex(0, g), vertex(1, g));
return 0;
}
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