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Thread: Palindrome program help

  1. #1
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    Default Palindrome program help

    I'm very new to programming and I'm in my first programming class. I was given a palindrome program and was asked to have the program test for palindromes while ignoring spaces and punctuation, I believe
    that I am on track to get this done but I don't know where I have gone wrong, does anyone have any suggestions?

    import java.util.Scanner;
     
    public class PalindromeTester
    {
       //-----------------------------------------------------------------
       //  Tests strings to see if they are palindromes.
       //-----------------------------------------------------------------
       public static void main (String[] args)
       {
          String str, another = "y";
          int left, right;
     
          Scanner scan = new Scanner (System.in);
     
          while (another.equalsIgnoreCase("y")) // allows y or Y
          {
             System.out.println ("Enter a potential palindrome:");
    		 String input = scan.nextLine();
             String strippedInput = input.replaceAll("\\W", "");
    		 str = scan.nextLine();
     
    		 }
     
    		 left = 0;
             right = str.length() - 1;
     
             while (str.charAt(left) == str.charAt(right) && left < right)
             {
                left++;
                right--;
             }
     
             System.out.println();
     
             if (left < right)
                System.out.println ("That string is NOT a palindrome.");
             else
                System.out.println ("That string IS a palindrome.");
     
             System.out.println();
             System.out.print ("Test another palindrome (y/n)? ");
             another = scan.nextLine();
          }
       }
    Last edited by timm1371; October 12th, 2011 at 08:48 PM.


  2. #2
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    Default Re: Palindrome program help

    Please do not duplicate threads...I have removed your other thread and moved this to a more appropriate location.

  3. #3

    Default Re: Palindrome program help

    String input = scan.nextLine();
    String strippedInput = input.replaceAll("\\W", "");
    str = scan.nextLine();
    What is the point of this code segment?

    After you ask for a palindrome, you assign it to strippedInput and then immediately expect more input. Why?

    while (str.charAt(left) == str.charAt(right) && left < right)
    {
    left++;
    right--;
    }


    System.out.println();

    if (left < right)
    System.out.println ("That string is NOT a palindrome.");
    else
    System.out.println ("That string IS a palindrome.");
    What if the string has an even number of chars? i.e., "pannap" that IS a palindrome
    Kenneth Walter
    Software Developer
    http://kennywalter.com

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