C# Program to find LCM

Posted in C# Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 167 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the domain of programming, solving mathematical problems is a common and necessary task. One such problem is finding the Least Common Multiple (LCM) of two numbers.

The LCM is the smallest positive integer that is divisible by both numbers without leaving a remainder.

In this tutorial, we'll explore a C# program that efficiently finds the LCM of two given numbers.

The logic behind this program involves utilizing the relationship between the greatest common divisor (GCD) and the LCM.

📄 Example

Let's dive into the C# code to achieve this functionality.

Program.cs

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using System;

class Program {
  // Function to find the GCD of two numbers
  static int FindGCD(int num1, int num2) {
    while (num2 != 0) {
      int temp = num2;
      num2 = num1 % num2;
      num1 = temp;
    }
    return num1;
  }

  // Function to find the LCM of two numbers
  static int FindLCM(int num1, int num2) {
    // LCM = (num1 * num2) / GCD(num1, num2)
    int gcd = FindGCD(num1, num2);
    return (num1 * num2) / gcd;
  }

  // Driver program
  static void Main() {
    // Replace these values with your desired numbers
    int number1 = 12;
    int number2 = 18;

    // Call the function to find the LCM
    int lcm = FindLCM(number1, number2);

    Console.WriteLine($"LCM of {number1} and {number2} is: {lcm}");
  }
}

💻 Testing the Program

To test the program with different numbers, simply replace the values of number1 and number2 in the Main method.

Output

LCM of 12 and 18 is: 36

Compile and run the program to see the LCM in action.

🧠 How the Program Works

The program defines a class Program containing static methods FindGCD to calculate the Greatest Common Divisor (GCD) and FindLCM to find the Least Common Multiple (LCM) using the GCD.
The driver program in the Main method sets the values of number1 and number2, calls the FindLCM method, and prints the result.

🧐 Understanding the Concept of LCM

Before delving into the code, let's take a moment to understand the concept of the Least Common Multiple (LCM).

The LCM of two numbers is the smallest positive integer that is divisible by both numbers without leaving a remainder.

For example, consider the numbers 12 and 18. The multiples of 12 are 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, ... The multiples of 18 are 18, 36, 54, 72, 90, 108, 126, 144, 162, 180, ... The LCM of 12 and 18 is 36.

🎢 Optimizing the Program

While the provided program is effective, there are more efficient algorithms for finding the LCM. Consider exploring and implementing optimized algorithms such as the prime factorization method.

Feel free to incorporate and modify this code as needed for your specific use case. Happy coding!