What must a convenience initializer call?

Which object allows you access to specify that a block of code runs in a background thread?

What is the inferred type of x? let x = ["a", "b", "c"]

How would you call a function that throws errors and also returns a value?

How do you designated a failable initializer?

In the function below, what are this and toThat examples of? func add(this x: Int, toThat y: Int)->{}

Output? class a1 { func cn10 { for var a = 9; a >=1; --a { for var b = 9; b >= 0; --b{ if b%2==a/2 [ print((b%4),terminator: "“) } } print("") }}} lets = a1() s.cn1()

What will be the output of the given Apple Swift code? var nm = 5.0 class abc[ var x = 0.0 var y: String [ return '\(nm)' ]

In Apple Swift, a class:

In Apple Swift, which of the following symbols is used to write an implicitly unwrapped optional?

ln Apple Swift, which of the following references should be used when it is known that the reference will never be nil during its lifetime?