Factorial example in Rust

Whilst it’s not the best use of recursion it’s a common tutorial and interview example. As Al Sweigart says “The Recursive Factorial Algorithm Is Terrible” ~ https://inventwithpython.com/recursion/chapter2.html#

Nevertheless, as a learning exercise, it’s a good way to get your feet wet.

One of they key concepts to understand is “stack unwinding” – which you can see a visualization of recursion here

But first, let’s look at the recursion example written in Rust – video:

Rust Factorial

fn main() {
    println!("{}", factorial(5));
}

fn factorial(x: i32) -> i32 {
    if x <= 1 {
        return 1;
    }
    x * factorial(x - 1)
}

Python Tutor visualization of the recursion

Python version of the Rust code:

def factorial(x):
    if x <= 1:
        return 1
    return (x* factorial(x-1))

print(factorial(5))

For more on Recursion, this is a great resource : https://inventwithpython.com/recursion/