C - Possible to create a tree level by level?

I'm studying trees right now, and I'd like to find some examples of how to create a binary(or k-ary) tree one level at a time, since I can't find it anywhere and my brain isn't working.

Anyone have any input on this? C's lack of functions doesn't help either. Thanks ahead, /prog/

i love how all the clique-kids sage any post that they recognize is not theirs