Declare a new variable with var, followed by a name, type, and value:
var num: Int = 10 var str: String = "Hello World!"
Variables can have their values changed:
num = 20 // num now equals 20
Unless they’re defined with let:
let num: Int = 10 // num cannot change
Swift infers the type of variable, so you don’t always have to declare variable type:
var ten = 10 // num is an Int var txt = "Hello!" // text is a String var pi = 3.14 // pi is a Double var floatPi: Float = 3.14 // floatPi is a Float