Re: [Boost-users] vertex_descriptor NULL check

On Wed, Mar 26, 2008 at 6:16 AM, Hardik Kheskani wrote:

I am using adjacent lists and using vertex_descriptors. Is there a way to check if the vertex_descriptor is NULL or 'not assigned' yet?

graph_traits < adjacent_list_graph >::vertex_descriptor vd ;

can I assign this to NULL ? and can I use vd == NULL or vd != NULL ?

Hi Hardik, graph_traits< adjacent_list_graph >::null_vertex() exists for just this purpose - to represent a vertex descriptor that should never be used as a valid vertex descriptor by the underlying graph. Regards, Aaron