Recursion

Recursion is when a function calls itself to solve a smaller version of the same problem.

Real-world analogy: Imagine you're looking for a document in a folder. You open the folder, but inside is another folder. You apply the same process to the inner folder. This continues until you find a folder with no subfolders (the base case).

Recursion is powerful for problems that are naturally self-referential: factorials, tree traversal, searching, sorting.