Smith Number...

A Smith number is a composite number, the sum of whose digits is the sum of the digits of its prime factors obtained as a result of prime factorization (excluding 1). The first few such numbers are 4, 22, 27, 58, 85, 94, 121 …..

Example :

1.    666

Prime factors are 2, 3, 3, and 37

Sum of the digits are (6+6+6)=18

Sum of digits of the factors (2+3+3+(3+7))=18

2.   4937775

Prime factors are 3, 5, 5, 65837

Sum of the digits are (4+9+3+7+7+7+5)=42

Sum of digits of the factors (3+5+5+(6+5+8+3+7))=42

Write a program to input a number and display whether the number is Smith number or not.

Sample data:

          Input 94               output                   Smith Number

          Input 102              output                   NOT Smith Number

          Input 666             output                   Smith Number

          Input 999              output                   NOT Smith Number

Solution:-

import java.util.*;

class Smith

{

     int number;

     static Scanner sc=new Scanner(System.in);

     void input()

     {

           System.out.println("Enter A Number");

           number=sc.nextInt();

     }

     int sum(int n)

     {

           int s=0;

           while (n!=0)

           {

                s=s+n%10;

                n=n/10;

           }

           return s;

     }

     void isSmith()//check for smith no.

     {

           int s1,s2=0;

           int cp=number;

           s1=sum(number);

           for(int i=2;cp!=1;i++)

           {

                while(cp%i==0)

                {

                     s2=s2+sum(i);

                     cp=cp/i;

                }

           }

           if(s1==s2)

           {

                System.out.println(number+" Is A Smith Number");

           }

           else

                System.out.println(number+" Is NOT A Smith Number");

     }

     public static void main(String args[])

     {

           Smith obj=new Smith();

           char ch='y';

           while(ch=='y')

           {

                obj.input();

                obj.isSmith();

                System.out.println("Do you want to continue Y/N");

                ch=sc.next().charAt(0);

           }

     }

}