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 countLeftNodes that returns the number of left children in the tree. A left child is a node that appears as the root of the left-hand subtree of another node. For example, reference tree #1 has 3 left children (the nodes storing the values 5, 1, and 4).

Reference Tree #1