Question

Problem 1. A palindrome is a sequence of characters that reads the same backward as forward. For example, each of the following five-digit integers is a palindrome: 12321, 55555, 45554 and 11611. Write an application that reads in a five-digit integer and determines whether it is a palindrome. If the number is not five digits long, display an error message and allow the user to enter a new value.

Problem 2. Modify the program to determine whether a seven-digit number is a palindrome. Before modifying, rename the files to Palindrome2.java and Palindrome2Test.java as file names.

Answer 1

As HOMEWORKLIB answer guidlines. If there are multiple questions then solve only one. I have solved the first one. Let me know if you have any doubts about it.

import java.util.*;

public class Palindrome
{
    public static void main(String args[]) throws Exception
    {
        Scanner s = new Scanner(System.in);
        System.out.print("Enter a 5-digit integer: ");
        String n=s.nextLine();
        if(n.length()!=5)
        {
            System.out.println("Number is not five digits long.");
            return ;
        }
        for(int i=0;i<2;i++)
            if(n.charAt(i)!=n.charAt(4-i))
            {
                System.out.println("Not a palindrome");
                return;
            }
        System.out.println("Palindrome");

    }
}