Question

Write a program in Java to check whether the given no. is niven no. or not.

Answer 1

Definition: Harshad Number In recreational mathematics, a Harshad number (or Niven number), is an integer (in base 10) that is divisible by the sum of its digits.

Let’s understand the concept of Harshad Number through the following example:

The number 18 is a Harshad number in base 10, because the sum of the digits 1 and 8 is 9 (1 + 8 = 9), and 18 is divisible by 9 (since 18 % 9 = 0)

The number 1729 is a Harshad number in base 10, because the sum of the digits 1 ,7, 2 and 9 is 19 (1 + 7 + 2 + 9 = 19), and 1729 is divisible by 19 (1729 = 19 * 91)

The number 19 is not a Harshad number in base 10, because the sum of the digits 1 and 9 is 10 (1 + 9 = 10), and 19 is not divisible by 10 (since 19 % 10 = 9)

The first few Harshad numbers in base 10 are:
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 18, 20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50, 54, 60, 63, 70, 72, 80, 81, 84, 90, 100, 102, 108, 110, 111, 112, 114, 117, 120, 126, 132, 133, 135, 140, 144, 150, 152, 153, 156, 162, 171, 180, 190, 192, 195, 198, 200 etc.

Programming Code:

/**
* The class HarshadNumber inputs a number and checks if it a Harshad Number or not
* @Program Type : BlueJ Program - Java
*/

import java.util.*;
class HarshadNumber
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);

System.out.print("Enter a number : ");
int n = sc.nextInt();
int c = n, d, sum = 0;

//finding sum of digits
while(c>0)
{
d = c%10;
sum = sum + d;
c = c/10;
}

if(n%sum == 0)
System.out.println(n+" is a Harshad Number.");
else
System.out.println(n+" is not a Harshad Number.");
}
}
Output:

Enter a number : 195
195 is a Harshad Number.
Enter a number : 194
194 is not a Harshad Number.
Enter a number : 190
190 is a Harshad Number.
Enter a number : 111
111 is a Harshad Number

Answer 2

import java.util.*;

class niven_number

{

   public static void main(String args[])

   {

       Scanner sc=new Scanner(System.in);

       System.out.println("Enter a number to check whether it is a niven number or not");

       int n=sc.nextInt();

       int d=0;

       int s=0;

       int cpy=n;

       while(n>0)

       {

           d=n%10;

           s=s+d;

           n=n/10;

       }

       if(cpy%s==0)

       {

           System.out.println(cpy+" is a niven number");

       }

       else

       {

           System.out.println(cpy+" is not a niven number");

       }

   }

}