Property Wrapper Question

DefaultUsingBackingStore.swift

var defaultNum = 1

class MyClass {
  var num: Int {
    get { _num ?? defaultNum }
    set { _num = newValue }
   }

  private var _num: Int?
}

let c = MyClass()
print("initial \(c.num)") // ✅ == 1

// changing the default changes the value returned
defaultNum = 2
print("dynamic \(c.num)") // ✅ == 2

// once the property is set, uses that value
c.num = 5
print("set     \(c.num)") // ✅ == 5