Why do we need separate “.swift” files for each class?

Question

Wondering if you might be able to answer a very basic beginner question for me. I’m working through the Cocoa + Swift tutorial on Lynda and I’m a little confused about class

Answer 1

You don't have to define just one class per file, but I would suggest doing so. I recently worked on a project for a client where there were several classes in some source files, and where some classes were defined in files who's names didn't match the class names. (This was in Objective-C, so each "file" was really a pair of files, a .h header file and a .m implementation file, but logically they were one.)

It was confusing as h*ll, and I wasted a fair amount of time fumbling around trying to find things.

Defining one class per file and making your filenames and class names match exactly is a good convention. It's like having each school subject in a separate binder. When you need to find a class you know exactly what file to open to find it.