FrequencyList File import javaio import javautil import ch08

FrequencyList File:

import java.io.*;
import java.util.*;
import ch08.trees.*;
import ch08.wordFreqs.*;

public class FrequencyList
{
public static void main(String[] args) throws IOException
{
String word;
WordFreq wordToTry;
WordFreq wordInTree;
WordFreq wordFromTree;

BinarySearchTree<WordFreq> tree = new BinarySearchTree<WordFreq>();
String skip; // skip end of line after reading integer

int numWords = 0;
int numValidWords = 0;
int numValidFreqs = 0;
int minSize;
int minFreq;
int treeSize;

// Set up file reading
FileReader fin = new FileReader(\"words.dat\");
Scanner wordsIn = new Scanner(fin);
wordsIn.useDelimiter(\"[^a-zA-Z0-9]\"); // delimiters are nonletters-digits

// Set up console reading
Scanner conIn = new Scanner(System.in);

//Get word and frequency limits from user
System.out.print(\"Minimum word size: \");
minSize = conIn.nextInt();
skip = conIn.nextLine();
System.out.print(\"Minimum word frequency: \");
minFreq = conIn.nextInt();
skip = conIn.nextLine();

while (wordsIn.hasNext()) // while more words to process
{
word = wordsIn.next();
numWords++;
if (word.length() >= minSize)
{
numValidWords++;
word = word.toLowerCase();
wordToTry = new WordFreq(word);
wordInTree = tree.get(wordToTry);
if (wordInTree == null)
{
// insert new word into tree
wordToTry.inc(); // set frequency to 1
tree.add(wordToTry);
}
else
{
// word already in tree, just increment frequency
wordInTree.inc();
}
}
}
  
treeSize = tree.reset(BinarySearchTree.INORDER);
System.out.println(\"The words of length \" + minSize + \" and above,\");
System.out.println(\"with frequency counts of \" + minFreq + \" and above:\");
System.out.println();
System.out.println(\"Freq Word\");
System.out.println(\"----- -----------------\");
for (int count = 1; count <= treeSize; count++)
{
wordFromTree = tree.getNext(BinarySearchTree.INORDER);
if (wordFromTree.freqIs() >= minFreq)
{
numValidFreqs++;
System.out.println(wordFromTree);
}
}

System.out.println();
System.out.println(numWords + \" words in the input file. \");
System.out.println(numValidWords + \" of them are at least \" + minSize + \" characters.\");
System.out.println(numValidFreqs + \" of these occur at least \" + minFreq + \" times.\");
System.out.println(\"Program completed.\");
}
}

54. Describe the effect that each of the following changes have on Fre would the quency List program. a. Remove the call to the useDelimiter method of the scanner class. b. Remove the call to the toLowerCase method of the string class. c. Change the call to the toLowercase method to a call to the to Upper Case method. d. In the else clause, change the statement word InTree inc to word- To Try inc

Solution

1.
   useDelimiter() methods are used to tokenize the Scanner input,
   With Scanner the default delimiters are the whitespace characters.
   So, if you remove \'useDelimiter()\', then Scanner tokenize input string by space.

2.
   So, if you remove toLowerCase method, then \'\'xYz\' and \'XYz\' will be two different element for BinarySearchTree
   Hence elements in BinarySearchTree will be case sensitive

3.
   replacing toLowerCase method with toUpper will not affect the frequency of words.

4.
   if you call wordInTree.inc() with wordToTry.inc(), then all the words will have frequency 1