foreach DFS/BFS for tree data-structure?

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On Thursday, 14 June 2018 at 11:31:50 UTC, Robert M. Münch wrote:
> I have a simple tree C data-structure that looks like this:
>
> node {
> 	node parent:
> 	vector[node] children;
> }
>
> I would like to create two foreach algorthims, one follwing the 
> breadth first search pattern and one the depth first search 
> pattern.
>
> Is this possible? I read about Inputranges, took a look at the 
> RBTree code etc. but don't relly know/understand where to start.

While it's possible to do with input ranges, it's not pretty and 
I'm not sure that it's as performant as the traditional method. I 
would recommend going with one of the other suggestions in this 
thread.