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COSC 2007 –Data Structures II Assignment #2 Due: Feb, 15, 2010 Building a BST The purpose of this question is to give you experience in implementing a simple spell checking program using binary search trees. One of the most-used applications of computers today is checking spelling. In this question, you will load a large dictionary (approximately 173,529 words) into a binary search tree. Then, you will walk through a text document, checking each word in the document against the dictionary; if the word is present, it is spelled correctly, and if not, indicate it as misspelled. In more detail, you will first load the dictionary (formatted in an alphabetical order of words) into a balanced binary search tree and display the height of the tree. Then read in input file and check the spelling of each word in the content against the dictionary. You are required to use the Binary Search Tree data structure to solve the problem. The SpellChecker program will ask user to enter two pieces of information: • the file name of the input file to be spell checked • the file name of the dictionary file The input file can be any text file. The format of the dictionary file is one word per line and the words are listed in an alphabetical order. An example of the content in the dictionary_small.txt is as follows (this is a small dictionary file for testing purpose). accomplices arraignments assemblyman awkwarder blowsiest communications concessionaire couldn't defrauded dumps fifteen honing incorrigibility lockout misting reeved splotch springboard typing woolgathering The program should output the possible misspelled words, and count the total number of words and as well as the number of misspelled words. Your program (SpellChecker.java) should behave similarly as follows: Spell Checker Application ------------------------------What is the input file for spelling check? test_large.txt What is the dictionary file? dictionary_large.txt The height of the binary search tree is 18. Spell checking ...done Possible misspelled words in the file: Armstrong France bruntal indiviidual clombing fuet L'Alpe d'Huez Armstrung menute widdening leed clusest challengor Ivan impesing Armstrong favourite Sundayy meake tims nooz Total number of words is 97. Possible number of misspelled words is 22. Hints on algorithm: • Store the dictionary into a balanced binary search tree data structure; • Use the algorithm taught in the lectures to construct a balanced binary search tree from the dictionary text file, where the words are sorted by their alphabetical order; • Read in the words from the input file and check whether they are presented in the dictionary; • Convert the word into lowercase before perform the checking. Numerical numbers are discarded from the spell check. Notes: • Your program must use the BinarySearchTree (TreeNode, BinaryTree, BinaryTreeBasis, TreeException) class to solve the problem. The files test_small.txt, dictionary_small.txt, test_large.txt and dictionary_large.txt can be used for testing your program. For this question, you should submit the SpellChecker.java class. Hand in your source code and the output after running your program.