Apple Swift Development II - Unit 3 - Vocats Test

If a variable can be set to any given structure, what is the variable’s type?

• Any

• as

• anyObject

• is

When is it appropriate to use the as! Operator?

• When you need to convert a value to an Any type

• When you need to downcast from one type to another, on the condition that the type is valid

• When you need to downcast from one type to another and you can guarantee the type is valid

• When you need to unwrap an optional

When you conditionally downcast from one type to another and store the value in a constant, which combination of keywords is used? Select all that apply.

• as!

• as?

• if let

• is

What is the result of the following block of code?

let sum = 99

func computSum(scores: [Int]) -> Int {

var sum = 0

for score in scores {

sum += score

}

return sum

}

computeSum(scores: [70, 30, 9])

• 0

• 00

• 109

• Compiler error; sum cannot be defined twice in the same scope

What is the result of the following block of code?

let sum = 99

func computeSum(scores: [Int]) -> Int {

var sum = 0

for score in scores {

sum += score

}

return sum

}

let sum = computeSum(scores: [70, 30, 9])

• 0

• 99

• 109

• Compiler error; sum cannot be defined twice in the same scope

Why is self in front of the property names of the initializer? Check all that apply.

struct ThemePark {

var name: String

var numEmployees: Int

var mostPopularRide: String

init(name: String, numEmployees: Int, mostPopularRide:

String) {

self.name = name

self.numEmployees = numEmployees

self.mostPopularRide = mostPopularRide

}

}

• It helps the reader distinguish between the parameters and properties with the same name

• self is always required when setting properties with an initializer

• It helps Swift compiler distinguish between the parameters and properties with the same name.

• self is not required

What property would you modify if you wanted to add a badge to a tab?

• badge

• badgelcon

• badgeString

• badgeValue

What value would you assign to the previous answer to hide a badge?

• nil

• 0

• " "

• ""

When should you use a controller?

• When you want to present many different tolls to the user

• When your app has distinct modes

• When you want to navigate from one view controller to another, within the same context

• Never

You can perform a segue programmatically as long as the segue has been

given a / an _____________________?

• Destination

• Identifier

• Outlet

• Source