~/very_nauty-1.0/examples/example_03.c.html

    #include "vn_graph.h"

    int main() {
      int j;
      graph_t g=graph_new(5);
      graph_add_edge(g,0,1);
      graph_add_edge(g,0,2);
      graph_add_edge(g,0,3);
      graph_add_edge(g,0,4);
      graph_add_edge(g,1,4);
      graph_show(g);
      printf("chi=%d\n",graph_chromatic_number(g,0));
      graph_make_dotfile_colored(g,"example_03.dot");
      graph_greedy_color(g,NULL);
      for (j=0; j<g->nnodes; j++) {
        if (visited(g,j)) {
          printf("node %d visited",j);
          printf(", color=%d",color(g,j));
          printf(", cluster=%d\n",cluster(g,j));
        }
      }
      printf("check_coloring=%d\n",graph_check_coloring(g));
      graph_clear(g);
      return 0;
    }