Question

Can you please write simple program with comments.

A Palindrome is a string that is spelled the same way forward and backward (example: radar).

Write a Java program that asks the user to input a string and tests whether the string is a Palindrome or not.

Display the message: "The string is a Palindrome" if it is, or "The string is NOT a Palindrome" if it is not.

Assume that the user will enter a string without any spaces. The string can be any length.

The String can contain letters(all lower case) and/or numbers or both.

Include any validation and exception handling needed to make the program work.

Upload your code to Canvas.

Answer 1

//PalindromeCheck.java
import java.util.Scanner;
public class PalindromeCheck {
    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);

        //Reading input from user
        System.out.print("Enter a string: ");
        String s = scanner.nextLine();

        boolean flag = true;

        // i is the starting index of the string s
        // j is the ending index of the string s
        int i = 0, j = s.length()-1;

        // Checking the value if character at index i with the character at index j
        // If characters match, then move i to its next position and j t its previous position
        // If characters does not match then the string is not a palindrome.
        // In the case of does not match update the value of flag to false and break the loop
        while(i<j){
            if(s.charAt(i)!=s.charAt(j)){
                flag = false;
                break;
            }
            i++;
            j++;
        }

        if (flag) {
            System.out.println("The string is a Palindrome");
        } else {
            System.out.println("The string is NOT a Palindrome");
        }
    }
}