Check Palindrome in Java Using Different Methods

import java.util.Scanner; // Import the Scanner class for user input

public class PalindromeChecker {

    public static void main(String[] args) {
        // Create a Scanner object to read user input
        Scanner scanner = new Scanner(System.in);

        // Prompt the user to enter a string
        System.out.print("Enter a string to check if it is a palindrome: ");
        String original = scanner.nextLine(); // Read the input string

        // Close the scanner as we no longer need it
        scanner.close();

        // Convert the string to lowercase to make the check case-insensitive
        original = original.toLowerCase();

        // Assume the string is a palindrome until proven otherwise
        boolean isPalindrome = true;

        // Initialize two pointers, one at the start and one at the end of the string
        int start = 0;
        int end = original.length() - 1;

        // Loop to compare characters from both ends
        while (start < end) {
            // Check if characters at start and end are different
            if (original.charAt(start) != original.charAt(end)) {
                isPalindrome = false; // Mark as not a palindrome
                break; // Exit the loop if a mismatch is found
            }
            // Move pointers towards the center
            start++;
            end--;
        }

        // Output the result
        if (isPalindrome) {
            System.out.println("The string \"" + original + "\" is a palindrome.");
        } else {
            System.out.println("The string \"" + original + "\" is not a palindrome.");
        }
    }
}

import java.util.Scanner; // Import the Scanner class for user input

public class PalindromeCheckerRecursive {

    // Recursive method to check if a substring is a palindrome
    public static boolean isPalindrome(String str, int start, int end) {
        // Base case: If pointers have crossed, it's a palindrome
        if (start >= end) {
            return true;
        }
        // Check if characters at the start and end are different
        if (str.charAt(start) != str.charAt(end)) {
            return false;
        }
        // Recursive call with moved pointers towards the center
        return isPalindrome(str, start + 1, end - 1);
    }

    public static void main(String[] args) {
        // Create a Scanner object to read user input
        Scanner scanner = new Scanner(System.in);

        // Prompt the user to enter a string
        System.out.print("Enter a string to check if it is a palindrome: ");
        String original = scanner.nextLine(); // Read the input string

        // Close the scanner as we no longer need it
        scanner.close();

        // Convert the string to lowercase to make the check case-insensitive
        original = original.toLowerCase();

        // Check if the string is a palindrome using recursion
        boolean isPalindrome = isPalindrome(original, 0, original.length() - 1);

        // Output the result
        if (isPalindrome) {
            System.out.println("The string \"" + original + "\" is a palindrome.");
        } else {
            System.out.println("The string \"" + original + "\" is not a palindrome.");
        }
    }
}