Happy number in java, program to check happy number

Happy number is similar to magic number, but instead of obtaining sum of the digits we obtain sum of square of the digits.

EXAMPLE-1

19 =1²+9²=82

82=8²+2²=68

68=6²+8²=100

100=1²+0²+0²=1

EXAMPLE-2

7=7²=49

49=4²+9²=97

97=9²+7²=130

130=1²+3²+0²=10

10=1²+0²=1

EXAMPLE-3

13=1²+3²=10

10=1²+0²=1

A java program on happy number can be made by extracting digits of the number then adding the square of the digits. If the sum result to 1 then it is a happy number and if it not results to 1 then if the sum is greater than 10 then it digits are re-extracted and then again added it's square of digits.

JAVA CODE-

import java.util.*;

public class happy

{

int n;

happy()

{

    n=0;

}

void getNum(int nx)

{

  n=nx;  

}

int sum_sq_digits(int d)

{

    int sum=0;

    while(d>0)

    {

        sum=sum+((d%10)*(d%10));

        d=d/10;

    }

    int s;int c=0;

    while(sum>9)

    {

        s=sum;

        while(s>0)

        {

            c=c+(s%10);

            s=s/10;

        }

        sum=c;

    }

    return sum;

}

void isHappy()

{

    if(sum_sq_digits(n)==1)

    System.out.println("it is a happy number");

    else

    System.out.println("it is not a happy number");

}

public static void main(String[] arg)

{

    Scanner sc=new Scanner(System.in);

    System.out.println("enter a number");

    int x=sc.nextInt();

    happy obj=new happy();

    obj.getNum(x);

    obj.isHappy();

}

}

Output-

enter a number 

19

It is a happy number

SIMILAR JAVA CODE-

1-Emirp number

2-Disarium number

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