text: //=======================================================================
  // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
  // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
  //
  // 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)
  //=======================================================================
  
  // Sample output:
  //
  //  The graph miles(100,0,0,0,0,10,0) has 405 edges,
  //   and its minimum spanning tree has length 14467.
  //
  
  #include <boost/config.hpp>
  #include <string.h>
  #include <stdio.h>
  #include <boost/graph/stanford_graph.hpp>
  #include <boost/graph/prim_minimum_spanning_tree.hpp>
  
  // A visitor class for accumulating the total length of the minimum
  // spanning tree. The Distance template parameter is for a
  // PropertyMap.
  template < class Distance >
  struct total_length_visitor : public boost::dijkstra_visitor<>
  {
      typedef typename boost::property_traits< Distance >::value_type D;
      total_length_visitor(D& len, Distance d) : _total_length(len), _distance(d)
      {
      }
      template < class Vertex, class Graph >
      inline void finish_vertex(Vertex s, Graph& g)
      {
          _total_length += boost::get(_distance, s);
      }
      D& _total_length;
      Distance _distance;
  };
  
  int main(int argc, char* argv[])
  {
      using namespace boost;
      Graph* g;
  
      unsigned long n = 100;
      unsigned long n_weight = 0;
      unsigned long w_weight = 0;
      unsigned long p_weight = 0;
      unsigned long d = 10;
      long s = 0;
      unsigned long r = 1;
      char* file_name = NULL;
  
      while (--argc)
      {
          if (sscanf(argv[argc], "-n%lu", &n) == 1)
              ;
          else if (sscanf(argv[argc], "-N%lu", &n_weight) == 1)
              ;
          else if (sscanf(argv[argc], "-W%lu", &w_weight) == 1)
              ;
          else if (sscanf(argv[argc], "-P%lu", &p_weight) == 1)
              ;
          else if (sscanf(argv[argc], "-d%lu", &d) == 1)
              ;
          else if (sscanf(argv[argc], "-r%lu", &r) == 1)
              ;
          else if (sscanf(argv[argc], "-s%ld", &s) == 1)
              ;
          else if (strcmp(argv[argc], "-v") == 0)
              verbose = 1;
          else if (strncmp(argv[argc], "-g", 2) == 0)
              file_name = argv[argc] + 2;
          else
          {
              fprintf(stderr,
                  "Usage: %s [-nN][-dN][-rN][-sN][-NN][-WN][-PN][-v][-gfoo]\n",
                  argv[0]);
              return -2;
          }
      }
      if (file_name)
          r = 1;
  
      while (r--)
      {
          if (file_name)
              g = restore_graph(file_name);
          else
              g = miles(n, n_weight, w_weight, p_weight, 0L, d, s);
  
          if (g == NULL || g->n <= 1)
          {
              fprintf(stderr, "Sorry, can't create the graph! (error code %ld)\n",
                  panic_code);
              return -1;
          }
  
          printf("The graph %s has %ld edges,\n", g->id, g->m / 2);
  
          long sp_length = 0;
  
          // Use the "z" utility field for distance.
          typedef property_map< Graph*, z_property< long > >::type Distance;
          Distance d = get(z_property< long >(), g);
          // Use the "w" property for parent
          typedef property_map< Graph*, w_property< Vertex* > >::type Parent;
          Parent p = get(w_property< Vertex* >(), g);
          total_length_visitor< Distance > length_vis(sp_length, d);
  
          prim_minimum_spanning_tree(g, p,
              distance_map(get(z_property< long >(), g))
                  .weight_map(get(edge_length_t(), g))
                  .
              // Use the "y" utility field for color
              color_map(get(y_property< long >(), g))
                  .visitor(length_vis));
  
          printf("  and its minimum spanning tree has length %ld.\n", sp_length);
  
          gb_recycle(g);
          s++;
      }
      return 0;
  }
  