The following exercises is a method to be added to the IntTree class from this chapter. Yo...

The following exercises is a method to be added to the IntTree class from this chapter. You may define additional private methods to implement your public method if necessary. Several problem descriptions refer to the following reference binary trees:

Write a method called countEmpty that returns the number of empty branches in a tree. An empty tree is considered to have one empty branch (the tree itself). For nonempty trees, your methods should count the total number of empty branches among the nodes of the tree. A leaf node has two empty branches, a node with one nonempty child has one empty branch, and a node with two nonempty children has no empty branches. For example, reference tree #1 has 7 empty branches (two under the value 1, one under 5, and two under each of 4 and 6).

Reference Tree #1