JuniorTheoryCommon

What does the program print (lines separated by spaces)?

SWIFT

class Book {
    deinit { print("bye") }
}

var anna: Book? = Book()
var boris = anna
anna = nil
print(1)
boris = nil
print(2)

1 bye 2

Expecting bye 1 2: thinking anna = nil frees the object. boris still holds a strong reference, so the object lives until boris = nil.
Expecting bye 1 bye 2: thinking var boris = anna copies the object. It copies the reference, so there is one object and deinit runs once.

JuniorTheoryCommon

SWIFT

class Book {
    deinit { print("bye") }
}

var anna: Book? = Book()
var boris = anna
anna = nil
print(1)
boris = nil
print(2)

1 bye 2

Expecting bye 1 2: thinking anna = nil frees the object. boris still holds a strong reference, so the object lives until boris = nil.
Expecting bye 1 bye 2: thinking var boris = anna copies the object. It copies the reference, so there is one object and deinit runs once.