*variables*
var age = 0 // implicit var declaration
var isCompleted:Bool = false // explicit var declaration
let num:Int = 2 // const takes less space than var
*strings*
var str1:String = "1+4 = \(1+4)" // "1+4 = 5"
*classes*
class MyClass:SomeSuperClass{
var myProperty:Int
override init(){...