C Program to Check Whether a Number is a Harshad Number or Not

Hey folks, today you will learn how to check whether a number is a Harshad number or not in the C programming language.

Let’s first know about Harshad number.

If a number is divisible by the sum of its digits, then that number is a Harshad Number. For example, 144 is a Harshad number because 1 + 4 + 4 = 9, and 144 is divisible by 9. Some other examples of Harshad numbers are 18, 27, 54, 156, 1729, and so on.

A Harshad number is also called a ‘Niven Number’.

The below program prompts the user to enter a number, then it displays the message whether the entered number is a Harshad number or not.

C Program to Check Whether a Number is a Harshad Number or Not

C Program

// C Program to Check Whether a Number is Harshad Number or Not
#include <stdio.h>

int main()
{
    int num, n, rem = 0, sum = 0;

    // Asking for input
    printf("Enter a number to check: ");
    scanf("%d", &num);

    n = num;

    // Calculating the sum
    while (num > 0)
    {
        rem = num % 10;
        sum = sum + rem;
        num = num / 10;
    }

    // Check whether number is equal to the sum
    if (n % sum == 0)
    {
        printf("%d is a harshad number.", n);
    }
    else
    {
        printf("%d is not a harshad number.", n);
    }

    return 0;
}

Output 1

Enter a number to check: 45
45 is a harshad number.

Output 2

Enter a number to check: 33
33 is not a harshad number.

How Does This Program Work?

    int num, n, rem = 0, sum = 0;

In this program, we have declared four int data type variables named num, n, rem, and sum.

    printf("Enter a number to check: ");
    scanf("%d", &num);

Then, the program prompts the user to enter a number. The scanf() function is used to read the number entered by the user and store it in the num variable.

    n = num;

We store the value of the original number in the n variable to use it later in the comparison.

    while (num > 0)
    {
        rem = num % 10;
        sum = sum + rem;
        num = num / 10;
    }

Then, we use a loop to calculate the sum of digits of the entered number. Suppose the user entered the number 45, then:

Iteration	rem = num % 10	sum = sum + rem	num = num /10
45 > 0	45 % 10 = 5	sum = 0 + 5 = 5	num = 45 / 10
4 > 0	4 % 10 = 4	sum = 5 + 4 = 9	num = 4 / 10

The sum will be 9.

Now, we check whether the original number is divisible by the sum of digits or not.

    if (n % sum == 0)
    {
        printf("%d is a harshad number.", n);
    }
    else
    {
        printf("%d is not a harshad number.", n);
    }

• If the original number is completely divisible by the sum of digits of the original number, then that number is a Harshad number.
• If the original number is not completely divisible by the sum of digits, then the entered number is not a Harshad number.

Conclusion

I hope after going through this tutorial, you understand how to check whether a number is a Harshad number or not using the C programming language.

You can use the same logic to check for Harshad number in other programming languages.