Chapter 2. Learning About Variables, Constants, Strings, and Operators

The first program I ever wrote was written in the BASIC programming language and was the typical Hello World application. This application was pretty exciting at first, but the excitement of printing static text wore off pretty quickly. For my second application, I used BASIC's input command to prompt the user for a name and then printed out a custom hello message to the user with their name in it. At the age of 12, it was pretty cool to display Hello Han Solo. This application led me to create numerous Mad Lib style applications that prompted the user for various words and then put those words into a story that was displayed after the user had entered all the required words. These applications introduced me to, and taught me, the importance of variables. Every useful application I created since then has used variables.

In this chapter, we will cover the following topics:

• What variables and constants are?
• What is the difference between explicit and inferred typing?
• What are numeric, string, and Boolean types?
• Defining what optional types are?
• Explaining how enumerations work in Swift?
• Explaining how Swift's operators work?