Harshad Number a number is divisible by sum of its digits

 Harshad Number:- A number is divisible by sum of its digits

A Harshad Number (or Niven Number) is an integer that is divisible by the sum of its digits. For example:

• 18 is a Harshad number because $18÷(1+8)=\mathrm{2 }$, which is divisible.
• 19 is not a Harshad number because $19÷(1+9)=1$, which is not divisible.

import java.util.*;

class HelloWorld {

    public static void main(String[] args) {

        int n=sc.nextInt();

        int sum=0,temp=n;

        while(temp!=0){

            sum+=temp%10;

            temp/=10;

        }

        System.out.print(n%sum==0?"yes":"no");

    }

}

How It Works

1. Input:

   • The program reads a number n from the user.

2. Calculate the Sum of Digits:

   • Use a while loop to repeatedly extract the last digit of the number (temp % 10).
   • Add the digit to the sum and remove it from the number by dividing temp by 10 (temp /= 10).

3. Check Divisibility:

   • Use the modulo operator (%) to check if n is divisible by sum.

4. Output:

   • Print "Yes" if the number is a Harshad number, otherwise print "No."

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Example Input and Output

Input:

18

Process:

• $1 + 8 = 9$
• $18 \mod 9 = 0$

Output:

Yes, 18 is a Harshad number.

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Input:

19

Process:

• $1 + 9 = 10$
• $19 \mod 10 \neq 0$

Output:

No, 19 is not a Harshad number.

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Edge Cases

1. Single-digit Numbers:

   • All single-digit numbers (1-9) are Harshad numbers since any number is divisible by itself.

2. Zero:

   • Mathematically, zero is not considered a Harshad num