Variables and types

We can declare variables as follows:

var a: Int = 1

In the preceding line of code, a is declared to be of type Int, with a value of 1. Since only an Int can be assigned the value 1, Swift can automatically infer the type of a, and it is not necessary to explicitly include the type information in the variable declaration:

var a = 1

In the preceding code, it is equally clear to both Swift and the reader what type a belongs to.

Note

What, no semicolons?You can add them if you want to, and you'll have to if you want to put two statements on the same line (why would you do that?). But no, semicolons belong to C and its descendants, and despite its many similarities to that particular family of languages, Swift has left the nest.

The value of a var can be changed by simply assigning to it a new value:

var a = 1 
a = 2 

However, in Swift, we can also declare a constant, which is immutable, using the let keyword:

let b = 2 

The value of b is now set permanently. The following attempt to...