Values are associated with classes, structs and enums using properties. Properties can come in two forms, the simplest being a stored property. Thankfully Swift makes life a little simpler than in the Objective-C world by doing away with instance variables. In Swift the functionality of Objective-C iVars and properties are brought together into a single property declaration.  This comes as either a constant (let) or variable (var) and can be assigned a default value where they’re declared, or thair value can be set or modified at initialization.