Reference Value Types Questions

reference-value-types.swift

import Foundation

// Question 1
struct Cat {
    var age: Int
}

var cat = Cat(age: 5)
var fluffyCat = cat
fluffyCat.age = 3

print("Cat's age is \(cat.age)")
print("Fluffy Cat's age is \(fluffyCat.age)")

////----------------------------------------
//// Question 2
class Dog {
    var age: Int

    init(age: Int) {
        self.age = age
    }
}

var dog = Dog(age: 5)
var playfulDog = dog
playfulDog.age = 10

print("Dog's age is \(dog.age)")
print("Playful Dog's age is \(playfulDog.age)")

//----------------------------------------
// Question 3.1
struct Computer {
    var screen: Screen
}

class Screen {
    var type: String

    init(type: String) {
        self.type = type
    }
}

let macbook1 = Computer(screen: Screen(type: "QLED"))
let pc1 = macbook1
macbook1.screen.type = "LCD"

print("Macbook's screen type: \(macbook1.screen.type)")
print("PC's screen type: \(pc1.screen.type)")

//----------------------------------------
// Question 3.2

let screen2 = Screen(type: "QLED")
let macbook2 = Computer(screen: screen2)
let pc2 = macbook2
screen2.type = "LCD"

print("Macbook's screen type: \(macbook2.screen.type)")
print("PC's screen type: \(pc2.screen.type)")

//----------------------------------------
// Question 3.3

let screen3 = Screen(type: "QLED")
let macbook3 = Computer(screen: screen3)
let pc3 = Computer(screen: screen3)
macbook3.screen.type = "LCD"

print("Macbook's screen type: \(macbook3.screen.type)")
print("PC's screen type: \(pc3.screen.type)")

//----------------------------------------
// Question 3.4
let macbook4 = Computer(screen: Screen(type: "QLED"))
let pc4 = Computer(screen: Screen(type: "QLED"))
macbook4.screen.type = "LCD"

print("Macbook's screen type: \(macbook4.screen.type)")
print("PC's screen type: \(pc4.screen.type)")

//----------------------------------------
// Question 4.1
class Plane {
    var cockpit: Cockpit

    init(cockpit: Cockpit) {
        self.cockpit = cockpit
    }
}

struct Cockpit {
    var hasPilot: Bool
}

var airbus1 = Plane(cockpit: Cockpit(hasPilot: true))
var boeing1 = airbus1
airbus1.cockpit.hasPilot = false

print("Airbus's cockpit has a pilot: \(airbus1.cockpit.hasPilot)")
print("Boeing's cockpit has a pilot: \(boeing1.cockpit.hasPilot)")

//----------------------------------------
// Question 4.2
var cockpit2 = Cockpit(hasPilot: true)
var airbus2 = Plane(cockpit: cockpit2)
var boeing2 = airbus2
cockpit2.hasPilot = false

print("Airbus's cockpit has a pilot: \(airbus2.cockpit.hasPilot)")
print("Boeing's cockpit has a pilot: \(boeing2.cockpit.hasPilot)")

//----------------------------------------
// Question 4.3
var cockpit3 = Cockpit(hasPilot: true)
var airbus3 = Plane(cockpit: cockpit3)
var boeing3 = Plane(cockpit: cockpit3)
airbus3.cockpit.hasPilot = false

print("Airbus's cockpit has a pilot: \(airbus3.cockpit.hasPilot)")
print("Boeing's cockpit has a pilot: \(boeing3.cockpit.hasPilot)")

//----------------------------------------
// Question 4.4
var airbus4 = Plane(cockpit: Cockpit(hasPilot: true))
var boeing4 = Plane(cockpit: Cockpit(hasPilot: true))
airbus4.cockpit.hasPilot = false

print("Airbus's cockpit has a pilot: \(airbus4.cockpit.hasPilot)")
print("Boeing's cockpit has a pilot: \(boeing4.cockpit.hasPilot)")

//----------------------------------------
// Question 5
func incrementer(amount: Int) -> () -> Int {
    var total = 0

    func sum() -> Int {
        total += amount
        return total
    }

    return sum
}

let inc = incrementer(amount: 5)

print(inc()) // ?
print(inc()) // ?
print(inc()) // ?