Chapter 10 — Recursively Recurse with Recursion

Recursion

When a function calls itself

Recursive function

A function that solves a problem by calling itself on a smaller version

Base case

The condition that stops recursion

Recursive case

The part where the function calls itself again

Progress toward base case

Each call must move closer to stopping

Infinite recursion

Recursive calls continue forever because no base case is reached

Call stack

Tracks unfinished function calls

Working back up

After the base case returns, paused calls resolve in reverse order

Stack overflow

Too many recursive calls fill the call stack

Factorial recursive case

number * factorial(number - 1)

Factorial base case

factorial(1) returns 1

Recursive filesystem search

Useful because folder depth may be unknown

Nested array recursion

If element is an array, recurse; otherwise process the valu