Question

JAVA:

4.31 (Palindromes) 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’s a palindrome. If the number is not five digits long, display an error message and allow the user to enter a new value.

Answer 1

import java.util.*; public class Palindromecheck{   public static void main(String args[]){   getnum();    } public static void getnum() { Scanner s=new Scanner(System.in); // scanner class in java used to take input from user System.out.println("enter number : \n"); // prompts the user to enter the number int n=s.nextInt(); // by using scanner class object s we take input from user String str = Integer.toString(n);// Converts given number to String if(str.length()==5) // if length of the string is 5 then calls prinum funciton { primenum(n); } else { System.out.println("Entered Number is not 5 in length"); getnum();} } public static void primenum(int n) { int k,rev=0,temp; temp=n;    while(n>0){    k=n%10; //getting remainder   rev=(rev*10)+k;    n=n/10;    }/* logic : calculate the reverse number and compare it with actual number if both are same then it is palindrome else not. */ if(temp==rev)    System.out.println("Entered Number is a palindrome");    else    System.out.println("It is not palindrome");    } }

Sample out of the program :