Not to put words into Hossein's mouth...but I'm going to. It sounds like he's looking for a data structure that represents a plain old tree - no ordering, just the parent/child relationships. A family tree (rooted at a single person) would be a good example.
That's exactly what I meant! But my concrete problem is some hierarchy in Civil Engineering.
I think this was discussed before on this mailing list, The (obvious) solution was to use a graph, and if necessary, add code that constrains it to satisfy the tree properties.
Apologies if I'm wrong. :P Not only you weren't wrong, but also you were
And how can I find the related emails? Can you remember the topic for those? perfectly right! Thanks, --Hossein __________________________________ Do you Yahoo!? Yahoo! Calendar - Free online calendar with sync to Outlook(TM). http://calendar.yahoo.com