Question

Fill in the code to complete the following method for checking whether a string is a palindrome. public static boolean isPalindrome(String s) { if (s.length() <= 1) // Base case return true; else if ________ return false; else return isPalindrome(s.substring(1, s.length() - 1)); }

Answer 1

Answer:

(s.charAt(0) != s.charAt(s.length()-1))

Explanation:

public class Palindrome

{

public static void main(String[] args) {

   

    System.out.println(isPalindrome("car"));

    System.out.println(isPalindrome("carac"));

 

}

   public static boolean isPalindrome(String s) {

       if (s.length() <= 1)

           return true;

       else if (s.charAt(0) != s.charAt(s.length()-1))

           return false;

       else

           return isPalindrome(s.substring(1, s.length() - 1));

   }

}

You may see the whole code above with two test scenarios.

The part that needs to be filled is the base case that if the character at position 0 is not equal to the character at the last position in the string, that means the string is not a palindrome. (If this condition meets, it checks for the second and the one before the last position, and keeps checking)