Program to Check if a Number is a Harshad Number in C++

Harshad Number

A Harshad number (also called a Niven number) is a number that is divisible by the sum of its digits. For example, 18 is a Harshad number because 1 + 8 = 9 and 18 is divisible by 9.

We will explore a method to check if a given number is a Harshad number using C++ programming.

Method: Using a while Loop

We extract each digit, sum them up, and check if the original number is divisible by this sum.

#include <iostream>
using namespace std;

bool isHarshad(int num) {
    int originalNum = num, sum = 0, digit;
    
    // Calculate the sum of digits
    while (num > 0) {
        digit = num % 10;
        sum += digit;
        num /= 10;
    }
    
    return (originalNum % sum == 0);
}

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    
    if (isHarshad(num))
        cout << num << " is a Harshad number";
    else
        cout << num << " is not a Harshad number";
    
    return 0;
}
            

Output:

Enter a number: 18
18 is a Harshad number