Question

I’m trying to write a program that converts a long into a string and checks if it is a palindrome, I’ve written the following so far, but it gives me an incompatible types error, and I can’t seem to find what’s causing it. :S
Any help would be much appreciated 🙂

The error occurs at line 24 and it says incompatible types – found void but expected java.lang.String

public class programPalindrome

{

private String go()
 {

  Input in = new Input ();
  System.out.print("Enter Number: ");
  return in.nextLine();
  long number = in.nextLong();
  String Palindrome = Long.toString(number); // converts the long into a string
  String newAnswer = reverse(Palindrome);
  String anotherAnswer = reverseCheck(Palindrome,newAnswer);
  System.out.println("This is a Palindrome" + Palindrome);
}
 // Check to see if the two argument Strings are the reverse of each
  // other. 

 private String reverseCheck(String Palindrome, String newAnswer)
{
  if (Palindrome.compareTo(newAnswer) == 0) {
    return System.out.println("It is a palindrome");
  }
  else
  {
    return System.out.println("It is not a palindrome");
  }
  }

  // Return a String which is the reverse of the argument String
  private String reverse(final String Palindrome)
  {
  String result = new String();
  int position = 0;
  while (position < Palindrome.length())
  {
    result = new Character(newAnswer.charAt(position)).toString() + result;
    position = position + 1;
  }
  return result;
 }


 public static void main(String[] args)
 {
  new programPalindrome().go();
 }
}

Answer 1

you can’t return System.out.println when your function signature says you want to return a String… you have some another syntax error on the line

result = new Character(newAnswer...

newAnswer can’t be resolved in that scope… are you using an IDE like Eclipse? That would probably help you out a lot.

Here’s a more straightforward program to do the same thing:

public class programPalindrome 

{ 

    static public boolean isPalindromic(long value){
        String valueAsString = Long.toString(value);
        String reverseString = (new StringBuffer(valueAsString)).reverse().toString();
        if(valueAsString.equals(reverseString)){
            return true;
        }
        else{
            return false;
        }
    }


    public static void main(String[] args) 
    {

        System.out.println(args[0] + " is palindromic == " 
                + isPalindromic(Long.parseLong(args[0])));
    } 
}