Classes are general-purpose, flexible constructs that become the building blocks of your program’s code. You define properties and methods to add functionality to your classes by using exactly the same syntax as for constants, variables, and functions.
Unlike other programming languages, Swift does not require you to create separate interface and implementation files for custom classes and structures. In Swift, you define a classin a single file, and the external interface to that class or structure is automatically made available for other code to use.
This video was developed by Skip Wilson. You can follow him on Twitter (@SkipAllMighty).