Happy_Number_14.java

import java.util.*;
public class Happy_Number_14
{     
    //isHappyNumber() will determine whether a number is happy or not  
    public static int isHappyNumber(int num)
    {  
        int rem = 0, sum = 0;  
        //Calculates the sum of squares of digits  
        while(num > 0){  
            rem = num%10;  
            sum = sum + (rem*rem);  
            num = num/10;  
        }  
        return sum;  
    }  

    public static void main(String[] args) 
    {  
        Scanner sc=new Scanner(System.in);
        System.out.println("Enter a number");
        int num =sc.nextInt();  
        int result = num;  
        while(result != 1 && result != 4){  
            result = isHappyNumber(result);  
        }  
        //Happy number always ends with 1  
        if(result == 1)  
            System.out.println(num + " is a happy number");  
        //Unhappy number ends in a cycle of repeating numbers which contains 4  
        else if(result == 4)  
            System.out.println(num + " is not a happy number");     
    }  
}