How do I implement a factorial function in Java?

How do I implement a factorial function in Java?

You can implement a factorial function in Java using recursion or iteration. Which method would you prefer?

I think recursion sounds interesting. Can you show me how to do that?

Sure! Here's a simple recursive implementation:

public class Factorial {
    public static int factorial(int n) {
        if (n == 0) return 1;
        return n * factorial(n - 1);
    }
}

You can call factorial(5) to get 120.

What if I want to handle negative numbers?

Good question! You can add a check at the beginning of the function to return an error or a specific value for negative inputs. Would you like to see that?