Swift Programming: The Big Nerd Ranch Guide, 3rd Edition

Chapter 2. Types, Constants, and Variables

This chapter will introduce you to Swift’s basic data types, constants, and variables. These elements are the fundamental building blocks of any program. You will use constants and variables to store values and to pass data around in your applications. Types describe the nature of the data held by the constant or variable. There are important differences between constants and variables, as well as each of the data types, that shape their uses.

Types

Variables and constants have a data type. The type describes the nature of the data and provides information to the compiler on how to handle the data. Based on the type of a constant or variable, the compiler knows how much memory to reserve and will ...