A variable is an easy-to-use placeholder that refers to the computer’s memory address.
Each variable in Swift specifies a specific type that determines how much memory the variable takes up, and different data types also determine the range of values that can be stored.
In the previous chapter, we have introduced basic data types, including integer
Int
, floating-point
Double
and
Float
, Boolean type Bool, and string type
String
. In addition, Swift also offers other more powerful data types such as
Optional
,
Array
,
Dictionary
,
Struct
, and
Class
.
Next we will show you how to declare and use variables in Swift programs. Variable declaration means telling the compiler where in memory to create how much storage space for the variable. 9.5.1. Variable declaration #