Swift quiz questions

What output will be produced by the code below?

var motto = "Bow ties are cool"
motto.replacingOccurrences(of: "Bow", with: "Neck")
print(motto)

1. "Bow ties are cool"

2. Not compile

When this code is executed, what value will num have?

let num = UInt.min

1. 16,777,216

2. 0

3. A random interger

When this code finishes executing, how many strings will the names array contain?

let names = [String]()
names.append("Amy")
names.append("Clara")
names.append("Rory")

1. 1

2. 2

3. 3

4. This code will not compile

What output will be produced by the code below?

import Foundation
let number = 16.0
print("\(number) squared is \(number * number), and its square root is \(sqrt(number))")

1. "16 squared is 16 * 16, and its square root is sqrt(16)"

2. "16.0 squared is 256.0, and its square root is 4.0"

3. Not compile

What output will be produced by the code below?

class Starship {
    var type: String
    var age: Int
}
let serenity = Starship(type: "Firefly", age: 24)
print(serenity.type)

1. "Firefly"

2. This code will not compile

What output will be produced by the code below?

let names = ["Amy", "Clara"]
for i in 0 ... names.length {
    print("Hello, \(names[i])!")
}

1. "Hello, Amy!"

2. This code will not compile

What output will be produced by the code below?

final class Dog {
    func bark() {
        print("Woof!")
    }
}
class Corgi : Dog {
    override func bark() {
        print("Yip!")
    }
}
let muttface = Corgi()
muttface.bark()

1. "Woof!", "Yip!"

2. This code will not compile

What output will be produced by the code below?

var i = 2
do {
    print(i)
    i *= 2
} while (i < 128)

1. 2, 4, 8, 16, 32, 64

2. This code will not compile

How many bits are used to store an Int?

1. 32-bit

2. 64-bit

3. It depends on the device

What output will be produced by the code below?

func sayHello(to name: String) -> String {
    return "Howdy, \(name)!"
}
print("\(sayHello(to: "Jayne"))")

1. "Howdy!"

2. "Howdy, Jayne!"

3. "Hello, Jayne!"

What output will be produced by the code below?

struct Spaceship {
    var name: String {
        willSet {
            print("I'm called \(newValue)!")
        }
    }
}
var serenity = Spaceship(name: "Serenity")
serenity.name = "TARDIS"

1. "I'm called Serenity!"

2. "I'm called TARDIS!"

What output will be produced by the code below?

let oneMillion = 1_000_000
let oneThousand = oneMillion / 0_1_0_0_0
print(oneThousand)

1. 1000000

2. 10000

3. 1000

What output will be produced by the code below?

import Foundation
let number = 16
print("\(number) squared is \(number * number), and its square root is \(sqrt(number))")

1. 16 squared is 256, and its square root is 4

2. Not compile

What output will be produced by the code below?

let names = ["Serenity", "Sulaco", "Enterprise", "Galactica"]
if let last = names.last {
    print(last)
}

1. "Galactica"

2. "Serenity"

3. "Enterprise"

4. "Sulaco"

When this code is executed, what will be the value of the j constant?

1. "5", "5"

2. "55"

3. Fail to compile

When this code is executed, what is the value of the swift string?

import Foundation
let ns = NSString("Hello")
let swift = String(ns)

1. Hello

2. This code will not compile.

3. Complie but not run

When this code is executed, what will the third constant contain?

let first = ["Sulaco", "Nostromo"]
let second = ["X-Wing", "TIE Fighter"]
let third = first + second

1. "Sulaco", "Nostromo"

2. "Sulaco", "Nostromo", "X-Wing", "TIE Fighter"

3. "Nostromo", "X-Wing", "TIE Fighter"

4. "X-Wing", "TIE Fighter"

Given the code below, what data type does i have?

let i = 10.2

1. Double

2. String

3. Decimal

4. Number

What output will be produced by the code below?

for i in 1...3 {
    print(i)
}

1. 1,2

2. 1, 2, 3

3. 1,2,3,4

What output will be produced by the code below?

let names = ["Serenity", "Sulaco", "Enterprise", "Galactica"]
for name in names where name.hasPrefix("S") {
    print(name)
}

1. "Serenity"

2. "Serenity", "Sulaco"

3. "Serenity", "Sulaco", "Enterprise"

4. "Sulaco"

5. Nothing will be output

6. This code will not compile