Abstract

(IN JAVA) In this lab you create an index for the complete works of William Shakespeare (pg100.txt), although you can use it on other files. It will test your ability to put together multiple data structures and objects.

Check each file to see what you must complete.

Your Assignment

We will create an IndexTree, a special type of Binary Search Tree. The IndexTree does a bit more than your standard tree, as we will use it to build an index of a file. This will be much like the index you find at the end of a textbook, where each topic is listed in alphabetical order with the pages it is found on. Since files dont have traditional pages to work off of, we will instead use line numbers. Furthermore, rather than building an index of only a few select topics, we will build an index over all the words in the file.

To do this, we use a special type of node. The IndexTree is made up of special IndexNodes. Rather than using generics, each IndexNode stores a word, the count of occurrences of that word, and a list of all lines that word appeared on (this means that each IndexNode will hold their own list). Nodes in the tree will be sorted by the String.

Use an IndexTree object to store an index of all the words that are in the provided text file, then display the index by performing an inorder traversal of the tree.

public class IndexTree {

// This is your root // again, your root does not use generics because you know your nodes // hold strings, an int, and a list of integers private IndexNode root; // Make your constructor // It doesn't need to do anything // complete the methods below // this is your wrapper method // it takes in two pieces of data rather than one // call your recursive add method public void add(String word, int lineNumber){ } // your recursive method for add // Think about how this is slightly different the the regular add method // When you add the word to the index, if it already exists, // you want to add it to the IndexNode that already exists // otherwise make a new indexNode private IndexNode add(IndexNode root, String word, int lineNumber){ return null; } // returns true if the word is in the index public boolean contains(String word){ return false; } // call your recursive method // use book as guide public void delete(String word){ } // your recursive case // remove the word and all the entries for the word // This should be no different than the regular technique. private IndexNode delete(IndexNode root, String word){ return null; } // prints all the words in the index in inorder order // To successfully print it out // this should print out each word followed by the number of occurrences and the list of all occurrences // each word and its data gets its own line public void printIndex(){ } public static void main(String[] args){ IndexTree index = new IndexTree(); // add all the words to the tree // print out the index // test removing a word from the index

} }

import java.util.List;

public class IndexNode {

// The word for this entry String word; // The number of occurrences for this word int occurences; // A list of line numbers for this word. List list; IndexNode left; IndexNode right; // Constructors // Constructor should take in a word and a line number // it should initialize the list and set occurrences to 1 // Complete This // return the word, the number of occurrences, and the lines it appears on. // string must be one line public String toString(){ return ""; } }