Understanding recursion

- Let's take a look at how recursion works,…and then, after we've done that, we will take a look…at how recursion is being used to walk…through all of this directory.…We'll see how "filepath-walk" is implemented…in the standard library…and we'll see recursion at use there.…To understand recursion, I think "factorial" is…the best example to begin with.…Here's the basic idea of recursion.…We have "func main" and, in here,…we're calling function, "factorial,"…and factorial's going to return an "int"…and we're passing into at "4" as an argument.…

Factorial has a parameter of wanting an int,…and we are passing in 4 as an argument.…Just making a distinction there…between parameter and argument.…What this does is, if x equals "zero,"…then we're going to return "one."…Otherwise, we're going to return "x"…multiplied by "factorial (x-1)."…We're calling factorial again, and we're passing…in a new number, and then that's…going to return a number.…There's functions nested within functions…nested within functions.…When you first come across this,…