Factorial Finder (Code) in Python

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Factorial Finder in Python

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About the project: create a Factorial Finder project in Python. This will be a self-contained script that allows you to calculate the factorial of a number.

This program will prompt you to enter a non-negative integer. It will then calculate and display the factorial of that number. The script will run in a continuous loop, so you can check as many numbers as you like without restarting.

How to use this Factorial Finder:

  • Run the Python script.
  • This script is ready to use. When you run it, you can enter a number, and it will immediately calculate and display its factorial.
  • You can keep entering numbers until you type q to quit.


Project Level: Beginner

You can directly copy the below snippet code with the help of green copy button, paste it and run it in any Python editor you have.

Steps: Follow these steps

Step 1: Copy below code using green 'copy' button.

Step 2: Paste the code on your chosen editor.

Step 3: Save the code with filename and .py extention.

Step 4: Run (Press F5 if using python IDLE)




# factorial_finder.py

def find_factorial(num):
    """
    Calculates the factorial of a non-negative integer.

    The factorial of a number is the product of all integers
    from 1 to that number. The factorial of 0 is 1.

    Args:
        num (int): The number for which to find the factorial.

    Returns:
        int: The factorial of the number.
    """
    # Factorial is not defined for negative numbers.
    if num < 0:
        return None
    # The factorial of 0 is 1.
    if num == 0:
        return 1
    
    # Calculate the factorial using a loop.
    factorial = 1
    for i in range(1, num + 1):
        factorial *= i
    return factorial

def main():
    """
    Main function to run the Factorial Finder in a continuous loop.
    """
    print("--- Python Factorial Finder ---")
    print("Enter a non-negative integer to find its factorial (or 'q' to quit).")

    while True:
        try:
            user_input = input("\nEnter a number: ").strip()

            # Check if the user wants to quit
            if user_input.lower() == 'q':
                print("Exiting Factorial Finder. Goodbye!")
                break
            
            num = int(user_input)
            
            if num < 0:
                print("Factorial is not defined for negative numbers. Please enter a non-negative integer.")
                continue

            result = find_factorial(num)
            
            # Print the result
            print(f"The factorial of {num} is {result}.")

        except ValueError:
            print("Invalid input. Please enter a valid integer.")

# This ensures that main() is called only when the script is executed directly.
if __name__ == "__main__":
    main()


The basic mathematical operations are suitable for beginners who learnt the basic concepts and started applying logic for their programs. Wring program code for Factorial calculation is very good option for new programmers.

It help learn and grow how to think for coding a program.


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