HappyNumber.java

//Happy Number
import java.util.Scanner;

class HappyNumber {
 int n = 0;

 public int splitDigits(int x) {
 n = 0; // Resetting n to 0 before splitting the digits
 while (x > 0) {
 int a = x % 10;
 x = x / 10;
 n += a * a;
 }
 return n;
 }

 public boolean isHappy() {
 int slow = n;
 int fast = n;

 do {
 slow = splitDigits(slow);
 fast = splitDigits(splitDigits(fast));
 } while (slow != fast);

 return slow == 1;
 }

 public static void main(String[] args) {
 Scanner input = new Scanner(System.in);
 int x = input.nextInt();
 HappyNumber obj = new HappyNumber();
 obj.splitDigits(x);
 boolean isHappy = obj.isHappy();

 if (isHappy) {
 System.out.println(x + " is a happy number");
 } else {
 System.out.println(x + " is not a happy number");
 }
 }
}