Swift Functional Programming - Second Edition

Type inference

Swift provides type inference. Swift infers the type of a variable, constant, or expression automatically, so we do not need to specify the types while defining them. Let's look at the following example:

let pi = 3.14159 var primeNumber = 691 let name = "my name" 

In this example, Swift infers pi as Double, primeNumber as Int, and name as String. If we need special types such as Int64, we will need to annotate the type.