source: downloads/boost_1_34_1/libs/graph/example/default-constructor.cpp @ 30

//=======================================================================
// 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/config.hpp>
#include <fstream>
#include <boost/graph/adjacency_list.hpp>

using namespace boost;

template < typename Graph > void
read_graph_file(std::istream & in, Graph & g)
{
  typedef typename graph_traits < Graph >::vertices_size_type size_type;
  size_type n_vertices;
  in >> n_vertices;             // read in number of vertices
  for (size_type i = 0; i < n_vertices; ++i)    // Add n vertices to the graph
    add_vertex(g);
  size_type u, v;
  while (in >> u)               // Read in pairs of integers as edges
    if (in >> v)
      add_edge(u, v, g);
    else
      break;
}


int
main()
{
  typedef adjacency_list < listS,       // Store out-edges of each vertex in a std::list
    vecS,                       // Store vertex set in a std::vector
    directedS                   // The graph is directed
  > graph_type;

  graph_type g;                 // use default constructor to create empty graph
  std::ifstream file_in("makefile-dependencies.dat");
  read_graph_file(file_in, g);

  assert(num_vertices(g) == 15);
  assert(num_edges(g) == 19);
  return 0;
}