C Program to find Factorial of a Number

Posted in C Tutorial

Updated on Jan 10, 2024

By Mari Selvan

👁️ 180 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the world of programming, solving mathematical problems is a fundamental skill. One such mathematical operation is finding the factorial of a number.

The factorial of a non-negative integer is the product of all positive integers less than or equal to that number. It's denoted by the symbol !.

In this tutorial, we'll explore a simple yet effective C program to calculate the factorial of a given number.

📄 Example

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

calculateFactorial.c

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#include <stdio.h>

// Function to calculate factorial
unsigned long long calculateFactorial(int num) {
  if (num == 0 || num == 1) {
    return 1;
  } else {
    return num * calculateFactorial(num - 1);
  }
}

// Driver program
int main() {
  // Replace this value with your desired number
  int number = 5;

  // Call the function to calculate factorial
  unsigned long long result = calculateFactorial(number);

  // Display the result
  printf("Factorial of %d is: %llu\n", number, result);

  return 0;
}

💻 Testing the Program

To test the program with a different number, replace the value of number in the main function.

Output

Factorial of 5 is: 120

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

🧠 How the Program Works

The program defines a function calculateFactorial that recursively calculates the factorial of a given number.
In the main function, replace the value of number with the desired input.
The program then calls the calculateFactorial function to compute the factorial.
The result is displayed using printf.

🧐 Understanding the Concept of Factorial

Before delving into the code, let's take a moment to understand the concept of factorial.

The factorial of a non-negative integer n, denoted as n!, is the product of all positive integers less than or equal to n.

For example, the factorial of 5 (5!) is calculated as 5 × 4 × 3 × 2 × 1 = 120.

🎢 Optimizing the Program

While the provided program is effective, it uses recursion to calculate the factorial. Depending on the input value, this approach may lead to a stack overflow for large numbers. Consider exploring iterative solutions for larger inputs or optimizing the recursive approach.

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