struct Dog {
  var name: String
  var weight: Int
}
var myDog = Dog(name: "Ranger", weight: 10)
var yourDog = myDog //Deep copy
yourDog.name = "Puncher"
print(myDog) // Dog(name: "Ranger", weight: 10)
print(yourDog) // Dog(name: "Puncher", weight: 10)