We can divide functions into two broad categories:

Built-In Functions

User-Defined Functions

User-defined functions are functions that users create themselves. We have a whole chapter dedicated to just these, so they aren’t of any concern to us now.

Built-in functions are functions which are predefined by Scala and are part of their libraries. All we have to do to use them is call their function name.

Built-in functions are known as methods.

The printing methods we looked at in the previous chapter are all built-in functions.