Re: [Boost-users] How to delete all vertices and edges in BGL

From: Douglas Gregor (doug.gregor_at_[hidden])
Date: 2005-07-12 08:25:06

On Jul 11, 2005, at 11:39 PM, Abhijit Deshmukh wrote:

> Hi,
>
> I have a mutable property undirected graph. I want to delete all the
> vertices and edges in the graph.
>
> I tried using the for loop
>
> 	for( b = *vertices( databaseGraph ).first; b!= *vertices(
> databaseGraph ).second; b++ ){
> 		clear_vertex( b, databaseGraph );
>                 remove_vertex( b, databaseGraph );
> 	}

The major problem here is that you shouldn't be dereferencing 
vertices(databaseGraph).second, because it is a past-the-end iterator. 
You could rewrite the loop as:

while (vertices(databaseGraph).first != vertices(databaseGraph).second) 
{
   b = *vertices(databaseGraph).first;
   clear_vertex(b, databaseGraph);
   remove_vertex(b, databaseGraph);
}

> Can you let me know what is the correct way of deleting all edges and
> vertices in a mutable property undirected graph.

The easy way is just "databaseGraph.clear()"

        Doug