Re: [Boost-users] In reply to: " edge function"

From: Stephan Diederich (stephan.diederich_at_[hidden])
Date: 2006-09-19 07:19:48

Hi Tom,

2006/9/19, Tom Lenaerts <tlenaert_at_[hidden]>:
>  Hi stephan,
[snip]

> I examined your code and adapted mine to yours and noticed that the error
> disappears
> when I change
>  g=new Graph();
> to
>  g=new Graph(1);
> in the member function parseFile.  It seems that this is the error that I
> made (as I expected it is a silly one). Could you tell me why the '1' is
> required here?

Quoting from ajacency-list docs:
>adjacency_list(vertices_size_type n,
>               const GraphProperty& p = GraphProperty())
>Creates a graph object with n vertices and zero edges.

You've just missed to add vertices to the graph. The call Graph(1)
creates an adjacency_list with one vertex (which was enough for my
example). Maybe you want to create a graph with "numnodes", which you
read from the beginning of your file.

Additionally you may want to have a look at the add_edge(..)
documentation, too. As it describes why your program worked with just
one vertex added in the beginning. (The others were created through
add_edge, if the first edge(...) call didn't fail, I think).

Cheers,
Stephan

btw: check http://www.boost.org/libs/tokenizer/index.html