| //======================================================================= |
| // 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; |
| } |