We wrote many of the supporting methods for the BinaryTree class recursively.  Some of these can also be written iteratively using a loop.

1. Rewrite the "depth()" method of the BinaryTree class iteratively.  Hint: You'll need to create a temporary variable.

2. Can you write the search method in a straightforward way iteratively?  If so, write it.  If not, explain why not (i.e. why is this problem different then depth).