This is the way of using indirect recursion in your code.
You can practice this more at Java Bat though.
Who said that recursion was difficult? Well, with this book, the past, present, and future walked into my head, and it was tense, all right, but not a good tense.
It certainly holds the reader's attention with ease, although I admit to enjoying Dark Matter more, there are times when this feels slightly more clunky on occasions.
In fact, the order in which we called the children, and added the current node's value didn't matter at all, because addition is commutative.
I have the ARC, and hopefully I'll get to it soon.