Happy Number

Happy Number is a number whose eventual sum of square of it’s digits is equal to 1.

Example 1: 19. 12+92 = 82. 82+22 = 68. 62+82 = 100. 12+02+02 = 1. Hence it is a Happy Number.

Java
import java.util.*;
public class HappyNumber
{
    public static void main(String args[])
    {
        int n=0,s=0,r=0,nCopy=0;
        Scanner sc=new Scanner(System.in);
        System.out.print("Enter a number: ");
        n=sc.nextInt();
        s=10;
        nCopy=n;
        while(s>9)
        {
            s=0;
            while(n>0)
            {
                r=n%10;
                s=s+(int)Math.pow(r,2);
                n=n/10;
            }
            n=s;
        }
        if(s==1)
        {
            System.out.println(nCopy+" is a Happy Number");
        }
        else
        {
            System.out.println(nCopy+" is not a Happy Number");
        }
    }
}
Java