Palindrome example

[Anand Shrivastava]

Dear friends,

I wrote the following code for checking a Palindrome (i.e. a string remains the same when reversed). However, it runs correctly only for one iteration of the loop, in the next iteration it takes the old value of the String from the console and does not wait for reading the new value. I cant understand why ? Kindly explain. The code is :

 import java.io.*;
public class Palindrome {
    private StringBuilder word=new StringBuilder();
    
    void setWord(String n)
     {
              word.setLength(0);  //Amended as suggested by ULF
              word.append(n);
      }
 
    boolean isPalindrome()
      {
return (word.toString().equalsIgnoreCase(word.reverse().toString()));
      }
 
    public static void main (String [] args) 
 
      {
           boolean more = true;
           char choice;
           String r;
           Palindrome p = new Palindrome();
   try {
           InputStreamReader is = new InputStreamReader(System.in);
   BufferedReader br = new BufferedReader(is);
           while (more)
           {
                 System.out.println("Enter word to check for Palindrome:");
 r=br.readLine();
                 p.setWord(r);
 System.out.println(p.isPalindrome());
                 r=p.isPalindrome()?"Yes it is":"No it isnt";
                 System.out.println(r);
                 System.out.println("Want more - Y/N:");
                 r=br.readLine();
                 choice=r.charAt(0);  // Amended as advised by ULF
                 switch (choice) {
                 case 'Y':
                 case 'y': more = true; break;
                 default: more = false;}
             }
             }
             catch (Exception E) {E.printStackTrace();}
 finally { r = null; }
                 
             }
       }
 
       
            

[ August 16, 2008: Message edited by: Anand Shrivastava ]
[ August 16, 2008: Message edited by: Anand Shrivastava ]

[Ulf Dittmer]

One thing that looks wrong is the setWord method. It should call word.setLength(0) before appending the new value.

[Anand Shrivastava]

Yes,i amended it. But even after that it does not wait for new input second time onwards.

[Ulf Dittmer]

My guess would be that the readLine reads the newline character that you need to type after the "y"/"n".

You may want to change the System.in.read call into a readLine as well, and then extract the first character from it.

[Anand Shrivastava]

Yes Ulf, you are right. You guys are genius. I dont know from where you learnt so much. Anyway, amending as per your advise.