C# Program to Check Harshad Number

Posted in C# Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 77 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, a Harshad number (or Niven number) is a positive integer that is divisible by the sum of its digits. Checking for Harshad numbers involves finding the sum of the digits and determining if the original number is divisible by this sum.

In this tutorial, we will explore a C# program designed to check whether a given number is a Harshad number.

📄 Example

Let's delve into the C# code that accomplishes this task.

IsHarshadNumber.cs

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using System;

class Program {
  // Function to check if a number is a Harshad number
  static bool IsHarshadNumber(int number) {
    int originalNumber = number;
    int sumOfDigits = 0;

    // Calculate the sum of digits
    while (number > 0) {
      sumOfDigits += number % 10;
      number /= 10;
    }

    // If the original number is divisible by the sum of digits, it is a Harshad number
    return (originalNumber % sumOfDigits == 0);
  }

  // Main method
  static void Main() {
    // Replace this value with the number you want to check
    int number = 18;

    // Call the function to check if the number is a Harshad number
    if (IsHarshadNumber(number)) {
      Console.WriteLine($"{number} is a Harshad number.");
    } else {
      Console.WriteLine($"{number} is not a Harshad number.");
    }
  }
}

💻 Testing the Program

To test the program with different numbers, modify the value of number in the Main method.

Output

18 is a Harshad number.

🧠 How the Program Works

The program defines a static method IsHarshadNumber that takes an integer number as input and returns true if the number is a Harshad number, and false otherwise.
Inside the method, it calculates the sum of the digits by iterating through the digits of the number.
If the original number is divisible by the sum of digits, the method returns true, indicating a Harshad number.
Inside the Main method, replace the value of number with the desired number you want to check.
The program calls the IsHarshadNumber method and prints the result.

📏 Between the Given Range

Let's delve into the C# code that checks for Harshad numbers in the specified range.

Program.cs

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using System;

class Program {
  // Function to check if a number is a Harshad number
  static bool IsHarshad(int number) {
    int sumOfDigits = 0;
    int originalNumber = number;

    // Calculate the sum of digits
    while (number > 0) {
      sumOfDigits += number % 10;
      number /= 10;
    }

    // Check if the original number is divisible by the sum of digits
    return (originalNumber % sumOfDigits == 0);
  }

  // Driver program
  static void Main() {
    Console.Write("Harshad numbers in the range 1 to 20: \n");

    for (int i = 1; i <= 20; i++) {
      if (IsHarshad(i)) {
        Console.Write(i + " ");
      }
    }

    Console.WriteLine();
  }
}

💻 Testing the Program

Output

Harshad numbers in the range 1 to 20:
1 2 3 4 5 6 7 8 9 10 12 18 20

Compile and run the program to see the Harshad numbers in the range from 1 to 20.

🧠 How the Program Works

The program defines a function IsHarshad that checks if a given number is a Harshad number.
Inside the function, it calculates the sum of the digits of the number.
The main function iterates through numbers from 1 to 20 and prints those that are Harshad numbers.

🧐 Understanding the Concept of Harshad Number

Before delving into the code, let's understand the concept of Harshad numbers. A Harshad number is a positive integer that is divisible by the sum of its digits.