in the tree app classthe main(routine inserts few data items into the tree it then presents character-based interface for the userwho can enter to see the treei to insert new data itemand to find an existing item here' some sample interactionenter first letter of showinsertor finds level= child= / level= child= / / level= child= / / enter first letter of showinsertor findf enter value to find found enter first letter of showinsertor findi enter value to insert enter first letter of showinsertor finds level= child= / level= child= /level= child= / / enter first letter of showinsertor findi enter value to insert enter first letter of showinsertor finds level= child= / / level= child= / / level= child= / level= child= / / the output is not very intuitivebut there' enough information to draw the tree if you want the levelstarting with at the rootis shownas well as the child number the display algorithm is depth-firstso the root is shown firstthen its first child and the subtree of which the first child is the rootthen the second child and its subtreeand so on the output shows two items being inserted and the second of these caused node (the root' child to split figure depicts the tree that results from these insertionsfollowing the final press of the key listing for tree java listing shows the complete tree java programincluding all the classes just discussed as with most object-oriented programsit' probably easiest to start by reeexamining the big picture classes first and then work down to the detail-oriented classes in this program this order is tree apptree nodedataitem