[Tree-hh] Why no root node?

[Shan Gao]

re-send this, in case not show up in mail list.

It seems breadth first iterator doesn't work. It only access all nodes under
the first top level node.

      tree<std::string> tr;

      std::cout << "empty tree to begin with:" << std::endl;
      print_tree(tr, tr.begin(), tr.end());

      tr.insert(tr.end(), "1");
      tr.insert(tr.end(), "2");
      tr.insert(tr.end(), "3");
      tr.insert(tr.end(), "4");
      std::cout<< "bfi printing..." << std::endl;
      for (tree<std::string>::breadth_first_iterator
bfi(tree<std::string>::iterator_base(tr.begin().node)); bfi != tr.end();
bfi++) {
          std::cout<< *bfi << std::endl;
      }

This results in segment fault. I am still not sure how to do conversion
among these different types of iterators safely.

On Fri, Nov 6, 2009 at 2:23 AM, Kasper Peeters
<kasper.peeters at durham.ac.uk>wrote:

> Hi Shan,
>
> > My question is why there is no root node? This tree class looks more
> > like a forest.
>
> Feel free to call it a forest if that helps you understand the
> structure. I simply decided to have the option of more than one node
> at the top, but you are free to never use that facility (i.e. just
> call 'set_head' to insert a root node and then only append children to
> that node, not siblings). It wasn't really a deep design issue.
>
> > The problem I got is there is no universal way to access all nodes,
> because
> > the nodes in the top level has no parent.
>
> I don't understand. What's wrong with simply iterating over all nodes
> from begin() to end() ? That will visit everything, including the
> nodes at the top level.
>
> Cheers,
> Kasper
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.hepforge.org/lists-archive/tree-hh/attachments/20091109/03cae994/attachment.htm