mutable.swift

struct SPerson {
  var name: String
  init(_ name: String) { self.name = name }
}

class CPerson {
  var name: String
  init(_ name: String) { self.name = name }
}

let sperson = SPerson("David")
sperson.name = "Frank"   // compiler error

let cperson = CPerson("David")
cperson.name = "Frank"   // this is ok, I want a way to express immutatibility on the class instance just as the struct