Question

WAP to check a Special number​

Answer 1

Solution.

The given co‎‎de is written in Java.

import java.util.*;

public class IsSpecial{

   static int fact(int n){

       if(n==0)

           return 1;

       return n * fact(n-1);

   }

   public static void main(String s[]){

       int n,a,sum=0;

       System.out.print("Enter a number: ");

       n=a=(new Scanner(System.in)).nextInt();

       for(;a!=0;a/=10)

           sum+=fact(a%10);

       if(sum==n)

           System.out.println("Number is a special number.");

       else

           System.out.println("Number is not a special number.");

   }

}

A special number is such a number whose sum of factorial of digits is equal to the number itself.

For example,

> 145 = 1! + 4! + 5!

Factorial of a number (n) means the product of all numbers from 1 to n.

> 5! = 1 × 2 × 3 × 4 × 5 and so on.

Logic.

• Accept the number.
• Calculate factorial of the digits present in the number. Add them up and store the sum in variable 'sum'.
• Check if sum is equal to the entered number or not. If true, number is special number or not.

See attachment for output.