Can you give an example solution in Python?

Can you give me an example solution in Python for calculating the factorial of a number?

Sure! Here's a simple example of a Python function to calculate the factorial:

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n - 1)

# Example usage:
print(factorial(5))  # Output: 120

What if I want to handle negative numbers?

You can modify the function to raise an exception for negative inputs. Here's an updated version:

def factorial(n):
    if n < 0:
        raise ValueError('Factorial is not defined for negative numbers')
    elif n == 0:
        return 1
    else:
        return n * factorial(n - 1)

Can you explain how recursion works in this example?

Of course! Recursion is when a function calls itself. In this case, factorial(n) calls factorial(n - 1) until it reaches the base case of n == 0. Each call waits for the result of the next call, building up the final result as it returns.

Thanks! Can you show me how to use loops instead of recursion?

Absolutely! Here's how you can calculate factorial using a loop:

def factorial(n):
    result = 1
    for i in range(1, n + 1):
        result *= i
    return result