Question

java program:

Please save the program with the name ‘Palindrome.java’

Write a method which return true if the string parameter is a palindrome.

This is the output example:

Lets check if a string is a palindrom

Please give me a string: abc

No, its not a Palindrom

Lets check if a string is a palindrom

Please give me a string: noon

Yes, its a Palindrom

Answer 1

//Program for checking string is palindrome or not.

//method isPalindrome is given which returns true when string is palindrome otherwise false

import java.util.Scanner;

public class Palindrome
{    //method for palindrome checking
    public static boolean isPalindrome(String str)
    {
        if(str.length() == 0 || str.length() == 1)
            // if length =0 OR 1 then it is
            return true;
        if(str.charAt(0) == str.charAt(str.length()-1))
            // initially check for first and last char of String:
            // if they are same then do the same thing for a substring.
            return isPalindrome(str.substring(1, str.length()-1));

        // if its not the case than string is not.
        return false;
    }

    public static void main(String[]args)
    {
        Scanner s = new Scanner(System.in);
        System.out.println("Lets check if a string is a palindrom");
        System.out.print("Please give me a string:");
        String str = s.nextLine();
        if(isPalindrome(str))
            System.out.println("Yes, its a Palindrom");
        else
            System.out.println("No, its not a Palindrom");
    }
}

/* Output

Lets check if a string is a palindrom                                                                                                                                    Please give me a string:abc                                                                                                                                              No, its not a Palindrom                                                                                                                                                                                                                                                                                 

Lets check if a string is a palindrom                                                                                                                                    Please give me a string:noon                                                                                                                                             Yes, its a Palindrom   

*/