Question

A happy number is a number in which the eventual sum of the square of the digits of the number is equal to 1.
Example:28=2^2+8^2=4+64=68
68=6^2+8^2=36+64=100
100=1^2+0^2+0^2=1 +0+0=1
Hence,28 is a happy number.
Example:12 =1^2+2^2=1+4=5
Hence, 12 is not a happy number.
Design a class Happy to check if a given number is a happy number.Some of the member of the class are given below:
Classname:Happy
Data members/ instance variables:
n: stores the number
Member functions:
Happy(): constructor to assign 0 to n
void getnum(int nn): to assign the parameter value to the number n=nn
int sum_sq_digits(int x): returns the sum of the square of the digit of the number x. using the recursive technique
void ishappy(): checks if the given number is a happy number by calling the function sum_sq_digits (int) and displays an appropriate message
Specify the class Happy giving details of the constructor( ). void getnum(int) , int sum_sq_digits(int) and void ishappy() . Also define a main() functionc to create an object and call the methods to check for happy number.

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Code

				
					import java.util.Scanner;
public class Happy
{
    int n;

    Happy()
    {
        n=0;
    }
    void getnum(int nn)
    {
        n=nn;
    }
    
    int sum_sq_digits(int x)
    {
        if(x==0)
        {
            return 0;
        }
        
        else
        {
            int rem=x%10; 
            return (rem * rem)+sum_sq_digits(x/10);
        }
    }
    void ishappy()
    {
        int x=n;
        while(x!=1 && x!=4)
        {
            x=sum_sq_digits(x);
        }
        if(x==1)
        {
            System.out.println(n+" IS A HAPPY NUMBER");
        }
        else
        {
            System.out.println(n+" IS NOT A HAPPY NUMBER");
        }
    }
    
    public static void main()
    {
        Scanner sc=new Scanner(System.in);
        System.out.println("Enter a number");
        int a=sc.nextInt();
        Happy ob1=new Happy( );
        ob1.getnum(a);
        ob1.ishappy();
    }
}