Part $1$: Binary Tree Traverals

In the BinaryTree.java file you will see three $(3)$ methods that you will finish.

Observe the methods, Node firstInNode$()$ and Node nextInNode$($Node w$).$ These methods are complete $-$

you do not need to modify them. The firstInNode$()$ method returns the first Node for an in$-$order traversal of the

A$4$Tree. Given a current Node as argument, nextInNode$($Node w$)$ returns the next Node in an in$-$order traversal of

the A$4$Tree. Using these methods it is possible to do an efficient, in$-$order traversal of an A$4$Tree.

You will complete similar methods for pre$-$order and post$-$order traversals. The methods nextPreNode$($Node

w$)$ and nextPostNode$($Node w$)$ are currently incomplete. nextPostNode$($Node w$)$ has a helper function, No