A86S

// variable and constant
var a = 10 // variable can be updated later
let PI = 3.14 // can not modify later

// Data types (Int, Float, Bool, Double, String) or Type Annotations
var age: Int = 10
var name:String = "John"
var radius: Float = 2.5
var area: Double = 14.50
var isAlive: Bool = false