StringTokenizer in a Palindrome program

[jeremyk]

Alright, this is my first time posting on here... haha, and i'm not 100% on how to exactly ask a question on this.. but anyhow, for anybody that does'nt know, a palindrome is a word that is spelt the same backwards and forwards.. like racecar. so i have this file and i am supposed to check if the words in it are palindromes using the stringtokenizer... so far i thought i had it until it only goes through the loop one time to check if it is a palindrome or not... where should i be putting the palindrome = isPalindrome(tokener.nextToken()); and the line = file.readLine(); so that it goes back through the loop?? ... i think thats what my problem is anyways.

[Norm]

Can you post your code so we can see it?

[jeremyk]

oh boy sorry it looks so bad, is there a way i can make that better?

[Norm]

To format it, use the code tags. You can get them from one of the icons above the input window. or [ CODE] [ /CODE] without the spaces
Label the end of long loops for ease of spotting them.
} // end of while thru input records

What/where is the problem with your code? Compile, runtime or output?

Add System.out.println() statements everywhere you need to see values and logic flow.

[jeremyk]

output, i have it trying to print at one point and all it gives me for the two counters ( counter and counter2 ) is one and one, so that means that it only goes through it twice... so im guessing the problem is with the reading of the next line somewhere rather...

[jeremyk]

 import java.io.*;                   // Neeeded for IOException.
import java.util.StringTokenizer;   // Needed for StringTokenizer.
import javax.swing.JOptionPane;     // Needed for JOptionPane.

public class TokenizerClass
{
    public static void main(String[] args) throws IOException
    {
        boolean palindrome = false;        // True or false palindrome
        double counter = 0.0;               // How many times true
        double counter2 = 0.0;              // How many times false
        double percentage = 0.0;            // Percent of palindromes
        
        // Get the file to be analyzed.
        FileReader fRead = new FileReader("as1q4.txt");
        BufferedReader file = new BufferedReader(fRead);
        
        // Get the first line of the file.
        String line = file.readLine();
        
        // Tokenize the first line of the String
        StringTokenizer tokener = new StringTokenizer(line);
        
        while (line != null)
        {
            boolean yesno = false;
            yesno = tokener.hasMoreTokens();
            if (yesno == true)
            {
                JOptionPane.showMessageDialog(null, "has more tokens..");
                // Uses the token in the string
                palindrome = isPalindrome(tokener.nextToken());
            }

            // If the word is a palindrome...
            if (palindrome == true )
            {
                // Adds one to the accumulator for the
                // calculation of percentage.
                counter ++;
                break;
            }
            // if the word is not a palindrome...
            else
            {
                // Adds one to the accumulator for the
                // calculation of percentage.
                counter2++;
            }
              line = file.readLine();

        }// end of while
        // Close the file
        file.close();
        
        JOptionPane.showMessageDialog(null, counter + " " + counter2);
        // Calculate the percentage of palindromes in the file. 
        percentage = counter / (counter + counter2) * 100;
        JOptionPane.showMessageDialog(null, "The words are " +
                                percentage + "% palindromes");
    }
    
     /**
     * The isPalindrome method returns a true or false value of
     * if the word evaluated was a palindrome or not.
     * @param inputWord the word to be evaluated. 
     * @return If the word is true or false. 
     */
    
    public static boolean isPalindrome(String inputWord)
    {
        boolean pal = true;         // If palindrome is true or false
        
        // Check if the word is a palindrome.
        for (int i = 0; i < inputWord.length() / 2; i++)
        {
            // If word is not palindrome change "pal" to false.
            if (!(inputWord.charAt(i) ==   
                       inputWord.charAt(inputWord.length() - i - 1)))
            {
               pal = false;
               break;
            }
            if (i == inputWord.length() / 2 - 1)
            {
                return true;
            }
        }return false;
    }
}

that better?

[Fubarable]

Hello caseyb22,
New To Java - Help with String Tokenizer! Urgent!

This current post is presented much better than the one on the forums.sun.com.

Good luck

[jeremyk]

owwwch. haha.

[Fubarable]

I agree with Norm that you should use the poor-man's debugger throughout your code (lots of System.out.println(...) statements). Also consider breaking this code into two smaller programs, one that reads the file, and one that checks strings to see if they are palindromes. debug the two programs separately, and then when both are working, combine them. It's the divide and conquer technique.

[jeremyk]

Okay thank you very much!

[DouglasDon]

The palindrome program I ran into was something like this:
import java.io.*;

public class Palindrome
{
public static void main (String[] args)
throws IOException
{
String line;
StringBuilder letterSequence, reverseLetterSequence;
BufferedReader in = new BufferedReader(new
InputStreamReader(System.in));

while ((line = in.readLine()) != null)
{
// ignore case and non-letter characters when checking
palindromes
line.toUpperCase();
letterSequence = lettersInCharSequence(line);
reverseLetterSequence = new StringBuilder(letterSequence);
reverseLetterSequence.reverse();

// after each line of input
// print "true" if the line is a palindrome, "false" otherwise
System.out.println(
letterSequence.length() > 0 // no 0-length
palindromes!
&&
(letterSequence.toString()).equals(reverseLetterSe quence.toString()));
}
}

private static StringBuilder lettersInCharSequence(CharSequence input)
{
StringBuilder letters = new StringBuilder();

for (int i = 0; i < input.length(); ++i)
if (Character.isLetter(input.charAt(i)))
letters.append(input.charAt(i));

return letters;
}
}