In Chapter 2, Building Blocks – Variables, Collections, and Flow Control, we developed a very simple program that helped organize a party. Even though we separated parts of the code in a logical way, everything was written in a single file and our functions were all lumped together. As projects grow in complexity, this way of organizing code is not sustainable. In the same way we use functions to separate out logical components in our code at scale, we also need to be able to separate out the logical components of our functions and data. To do this, we can define code in different files and we can also create our own types that contain custom data and functionality. These types are commonly referred to as objects, as a part of the programming technique called object-oriented programming. In this chapter we will cover the following:
Structs
Classes and inheritance
Enumerations
Projects
Extensions
Scope
Access control