Fork and clone this repo. On your fork, answer and commit the follow questions. When you are finished, submit the link to your repo on Canvas.
Given this class that represents a giant:
class Giant {
var name: String = "Fred"
var weight: Double = 340.0
let homePlanet: String = "Earth"
}
let fred = Giant() //Fred is an instance of Giant. If you make another variable, George, and assign it the value of fred, changing fred at any point later on would also modify George due to the logic behind reference types.Will these three lines of code run? If not, why not?
fred.name = "Brick" //Yes
fred.weight = 999.2 // Yes
fred.homePlanet = "Mars" //No. homePlanet is a constant so is not mutable.Fix the class definition for Giant in the space below so that it does work:
class Giant {
var name: String = "Fred"
var weight: Double = 340.0
var homePlanet: String = "Earth" //This is the changed line. let > var.
}
let fred = Giant()
Take a look at this struct that represents an alien:
struct Alien {
var name: String
var height: Double
var homePlanet: String
}
let bilbo = Alien(name: "Bilbo", height: 1.67, homePlanet: "Venus")var bilbo = Alien(name: "Bilbo", height: 1.67, homePlanet: "Venus") is an instance of Alien. If you make another variable, Shmalien, and assign it the value of Alien, changing Alien at any point later on would NOT modify Shmalien due to the rules of a struct type.
Will these three lines of code run? If so, why not?
bilbo.name = "Jake" //No
bilbo.height = 1.42 //No
bilbo.homePlanet = "Saturn" //No
//Reason why none work is because 'bilbo' is a constant. Change the declaration of bilbo so that the above three lines of code do work:
var bilbo = Alien(name: "Bilbo", height: 1.67, homePlanet: "Venus")
Consider this bit of code that uses the Giant class:
let edgar = Giant()
edgar.name = "edgar"
let jason = edgar
jason.name = "Jason"What will the value of edgar.name be after those three lines of code are run? What will the value of jason.name be? Why?
The value of both edgar.name and jason.name will be "Jason". This is because a reference type object, which class is, both point to the original value instead of creating a new value when you set a variable equal to an instance. So modifying edgar or jason will modify both edgar and jason since jason = edgar.
Given this bit of code that uses the Alien struct:
var charles = Alien(name: "Charles", height: 2.25, homePlanet: "Pluto")
var charlesFromJupiter = charles
charlesFromJupiter.homePlanet = "Jupiter"What will the value of charles.homePlanet be after the above code run? What about the value of charlesFromJupiter.homePlanet? Why?
Charles will have the same as it did when it was declared ("Pluto"). Becaue a struct is a value type object, changing the value of a variable "forked" from it will not modify the original value since it's saved in a different space in memory.
charlesFromJupiter.homeplanet //will have the same value it was given when it itself was assigned. "Jupiter"
Here's a struct that represents a bank account:
struct BankAccount {
var owner: String
var balance: Double
func deposit(_ amount: Double) {
balance += amount
}
func withdraw(_ amount: Double) {
balance -= amount
}
}Does this code work? Why or why not?
No. Because if it did, the next question wouldn't ask us to fix it.
Also, balance isn't mutable unless the function is written as a mutating func
Fix the BankAccount struct so it does work.
struct BankAccount {
var owner: String
var balance: Double
mutating func deposit(_ amount: Double) { //Must be mutating because bal
balance += amount
}
mutating func withdraw(_ amount: Double) {
balance -= amount
}
}
Given the code below (which should incorporate any fixes you made):
var joeAccount = BankAccount(owner: "Joe", balance: 100.0)
var joeOtherAccount = joeAccount
joeAccount.withdraw(50.0)What will the value of joeAccount.balance be after the above code runs? What about the value of joeOtherAccount.balance? Why?
joeAccount balance will be $50.0 and joeOtherAccount.balance will be $100.0. This is BankAccount is a value type (struct) so when joeOtherAccount was declared, it can be thought of as a snapshot of joeAccount in that moment. In other words, it's saved to a different space in memory and so modifying joeAccount later on will not modify joeOtherAccount.
a. Write a struct called Person that has 3 properties of type String: a first name, a last name and a middle name. Have the middle name be optional. Create 2 instances of a Person, one with a middle name and one without. Print one of their first names.
b. Write a method in Person called fullName that will return a formatted string of an instance's full name. Call this method on both the instances you created in part a.
struct Person {
let firstName: String
let middleName: String?
let lastName: String
func fullName () -> String {
if let middleName = middleName { //This unwraps the middle name if it exists and interpolates the name constants into the string.
return "\(firstName) \(middleName) \(lastName)"
} else {
return "\(firstName) \(lastName)"
}
}
}
var person1 = Person(firstName: "Nicholas", middleName: nil, lastName: "White")
var person2 = Person(firstName: "Timothy", middleName: "Cornelius", lastName: "Locke")
print(person2.fullName())
print(person1.fullName())
a. Create a struct called Book that has properties title, author and rating, of type String, String, and Double respectively. Create some instances of Book.
b. Add a method to Book called isGood that returns true if its rating is greater than or equal to 7
struct Book {
var title: String
var author: String
var rating: Double
func isGood () -> Bool {
if rating >= 7.0 {
return true
} else {
return false
}
}
}
let crappyBook = Book(title: "Twilight" , author: "Stephanie Meyer" , rating: 0.0)
let goodBook = Book(title: "Breakfast of Champions", author: "Kurt Vonnegut", rating: 10.0)
goodBook.isGood()
class Dog {
}Work through the following tasks one by one, in order. Each time, add to the Dog class above. Each task has sample output that you should be able to replicate when you are done.
a. Give Dog four properties, all with default values: name (string), breed (string), mood (string), and hungry (boolean).
b. Add an instance method called playFetch(). It should set the dog's hungry property to true, set its mood property to playful, and print "Ruff!"
c. Add an instance method called feed(). If the dog is hungry, it should set hungry to false and print "Woof!" If the dog is not hungry, it should print "The dog doesn't look hungry"
d. Add an instance method called toString that returns a String type description of the dog:
class Dog {
var name: String
var breed: String
var mood: String
var hungry: Bool
init (name: String, breed: String, mood: String, hungry: Bool) {
self.name = name
self.breed = breed
self.mood = mood
self.hungry = hungry
}
func playFetch() {
hungry = true
mood = "playful"
print("Ruff!")
}
func feed() {
hungry = false
print("Woof!")
if hungry == false {
print("The dog doesn't look hungry...")
}
}
func toString () -> String {
return """
Name: \(name)
Breed: \(breed)
Mood: \(mood)
"""
}
}
var dog1 = Dog(name: "Chaucer", breed: "Affenpinscher", mood: "weird", hungry: false)
dog1.playFetch()
dog1.feed()
dog1.toString()
print(dog1.toString())e. Add a type property called count that keeps track of how many dogs have been created so far.
//Ex: There have been four dogs created so far
Dog.count //returns 4
There are three common scales that are used to measure temperature: Celsius, Fahrenheit, and Kelvin:
C = (F - 32) / 1.8 F = 1.8 * C + 32 K = C + 273
a. Make a struct called FreezingPoint that has three static properties: celsius, fahrenheit, and kelvin. Give them all values equal to the freezing point of water.
b. Make a struct called Celsius that has one property: celsius, and two methods getFahrenheitTemp, and getKelvinTemp. Make the values of fahrenheit and kelvin correct values, converted from the celsius property.
var tenDegreesCelsius = Celsius(celsius: 10.0)
tenDegreesCelsius.celsius //returns 10.0
tenDegreesCelsius.getKelvinTemp() //returns 283.0
tenDegreesCelsius.getFahrenheitTemp() //returns 50.0c. Give the Celsius struct a method called isBelowFreezing that returns a Bool (true if the temperature is below freezing).
struct FreezingPoint {
let Celsius = 0
let Farenheit = 32
let Kelvin = 273
}
struct Celsius {
let celsius: Double
func getFahrenheitTemp() -> Double {
return 1.8 * celsius + 32
}
func getKelvinTemp () -> Double {
return celsius + 273
}
func isBelowFreezing () -> Bool {
if celsius < 0 {
return true
} else {
return false
}
}
}
var tenDegreesCelsius = Celsius(celsius: 10.0)
tenDegreesCelsius.celsius
tenDegreesCelsius.getKelvinTemp()
tenDegreesCelsius.getFahrenheitTemp()
tenDegreesCelsius.isBelowFreezing()
Create a struct called RGBColor that has 3 properties, red, green, blue that are all of type Double.
Given the below array of color dictionaries, create an array of RGBColor.
let colorDictArray: [[String: Double]] = [["red": 1.0, "green": 0.0, "blue": 0.0],
["red": 0.0, "green": 1.0, "blue": 0.0],
["red": 0.0, "green": 0.0, "blue": 1.0],
["red": 0.6, "green": 0.9, "blue": 0.0],
["red": 0.2, "green": 0.2, "blue": 0.5],
["red": 0.5, "green": 0.1, "blue": 0.9],]struct RGBColor {
var red: Double
var green: Double
var blue: Double
}
let colorDictArray: [[String: Double]] = [["red": 1.0, "green": 0.0, "blue": 0.0],
["red": 0.0, "green": 1.0, "blue": 0.0],
["red": 0.0, "green": 0.0, "blue": 1.0],
["red": 0.6, "green": 0.9, "blue": 0.0],
["red": 0.2, "green": 0.2, "blue": 0.5],
["red": 0.5, "green": 0.1, "blue": 0.9],]
var rgbArray = [RGBColor]()
for dict in colorDictArray {
rgbArray.append(RGBColor(red: dict["red"]!, green: dict["green"]!, blue: dict["blue"]!))
}
print(rgbArray[0])
a. Create a struct called Movie that has properties for name (String), year (Int), genre (String), cast ([String]), and description (String). Create an instance of your Movie class
b. Create an instance method inside Movie called blurb that returns a formatted string describing the movie.
Ex: "Borat came out in 2006. It was an odd film starring Sacha Baron Cohen as a man named Borat who was visiting America from Kazakhstan."
struct Movie {
let name: String
let year: Int
let genre: String
let cast: [String]
let description: String
func blurb () -> String {
return "\(name), released in \(year) was a true masterpiece of cinema. Starring the enigmatic \([cast[0]].joined()) as Johnny and \([cast[1]].joined()) as his best friend, Mark, \(description)."
}
}
var myMovie = Movie(name: "The Room", year: 2003, genre: "Drama", cast: ["Tommy Wiseau", "Greg Sestero", "Juliette Danielle", "Philip Haldiman"], description: "this movie can't even be described, honestly")
print(myMovie.blurb())
Create a function outside of your Movie struct called makeMovie that takes in a dictionary of type [String: Any], like dieHardDict below, and returns an optional Movie. Use dieHardDict to create an instance of a Movie.
let dieHardDict: [String: Any] = ["name": "Die Hard",
"year" : 1987,
"genre": "action",
"cast": ["Bruce Willis", "Alan Rickman"],
"description": "John Mclain saves the day!"]Hint: To use a value type Any, you will need to cast it to its expected type.
Below, nameAsAny is of type Any because thats the type of the value in the dictionary:
if let nameAsAny = dieHardDict["name"] {
print(nameAsAny)
}Below, nameAsString is of type String because the optional binding is attempting to cast it as a String.
if let nameAsString = dieHardDict["name"] as? String {
print(nameAsString)
}If the binding fails it returns nil. 1987 cannot be cast as a String because it is a number.
if let yearAsString = dieHardDict["year"] as? String {
print(yearAsString)
} else {
print("this didn't work")
}Given the below array of movie dictionaries, use your function from the last question to create a Array of Movie.
// movies is an Array of Dictionaries
// each element of movies is a Dictionary with the keys
// 'name','year', 'genre', 'cast' and 'description'
var movies: [[String:Any]] = [
[
"name": "Minions",
"year": 2015,
"genre": "animation",
"cast": ["Sandra Bullock", "Jon Hamm", "Michael Keaton"],
"description": "Evolving from single-celled yellow organisms at the dawn of time, Minions live to serve, but find themselves working for a continual series of unsuccessful masters, from T. Rex to Napoleon. Without a master to grovel for, the Minions fall into a deep depression. But one minion, Kevin, has a plan."
],
[
"name": "Shrek",
"year": 2001,
"genre": "animation",
"cast": ["Mike Myers", "Eddie Murphy", "Cameron Diaz"],
"description": "Once upon a time, in a far away swamp, there lived an ogre named Shrek whose precious solitude is suddenly shattered by an invasion of annoying fairy tale characters. They were all banished from their kingdom by the evil Lord Farquaad. Determined to save their home -- not to mention his -- Shrek cuts a deal with Farquaad and sets out to rescue Princess Fiona to be Farquaad\"s bride. Rescuing the Princess may be small compared to her deep, dark secret."
],
[
"name": "Zootopia",
"year": 2016,
"genre": "animation",
"cast": ["Ginnifer Goodwin", "Jason Bateman", "Idris Elba"],
"description": "From the largest elephant to the smallest shrew, the city of Zootopia is a mammal metropolis where various animals live and thrive. When Judy Hopps becomes the first rabbit to join the police force, she quickly learns how tough it is to enforce the law."
],
[
"name": "Avatar",
"year": 2009,
"genre": "action",
"cast": ["Sam Worthington", "Zoe Saldana", "Sigourney Weaver"],
"description": "On the lush alien world of Pandora live the Na\"vi, beings who appear primitive but are highly evolved. Because the planet\"s environment is poisonous, human/Na\"vi hybrids, called Avatars, must link to human minds to allow for free movement on Pandora. Jake Sully, a paralyzed former Marine, becomes mobile again through one such Avatar and falls in love with a Na\"vi woman. As a bond with her grows, he is drawn into a battle for the survival of her world."
],
[
"name": "The Dark Knight",
"year": 2008,
"genre": "action",
"cast": ["Christian Bale", "Heath Ledger", "Aaron Eckhart"],
"description": "With the help of allies Lt. Jim Gordon and DA Harvey Dent, Batman has been able to keep a tight lid on crime in Gotham City. But when a vile young criminal calling himself the Joker suddenly throws the town into chaos, the caped Crusader begins to tread a fine line between heroism and vigilantism."
],
[
"name": "Transformers",
"year": 2007,
"genre": "action",
"cast": ["Shia LaBeouf", "Megan Fox", "Josh Duhamel"],
"description": "The fate of humanity is at stake when two races of robots, the good Autobots and the villainous Decepticons, bring their war to Earth. The robots have the ability to change into different mechanical objects as they seek the key to ultimate power. Only a human youth, Sam Witwicky can save the world from total destruction."
],
[
"name": "Titanic",
"year": 1997,
"genre": "drama",
"cast": ["Leonardo DiCaprio", "Kate Winslet", "Billy Zane"],
"description": "The ill-fated maiden voyage of the R.M.S. Titanic; the pride and joy of the White Star Line and, at the time, the largest moving object ever built. She was the most luxurious liner of her era -- the \"ship of dreams\" -- which ultimately carried over 1,500 people to their death in the ice cold waters of the North Atlantic in the early hours of April 15, 1912."
],
[
"name": "The Hunger Games",
"year": 2012,
"genre": "drama",
"cast": ["Jennifer Lawrence", "Josh Hutcherson", "Liam Hemsworth"],
"description": "Katniss Everdeen voluntarily takes her younger sister\"s place in the Hunger Games, a televised competition in which two teenagers from each of the twelve Districts of Panem are chosen at random to fight to the death."
],
[
"name": "American Sniper",
"year": 2014,
"genre": "drama",
"cast": ["Bradley Cooper", "Sienna Miller", "Kyle Gallner"],
"description": "Navy S.E.A.L. sniper Chris Kyle\"s pinpoint accuracy saves countless lives on the battlefield and turns him into a legend. Back home to his wife and kids after four tours of duty, however, Chris finds that it is the war he can\"t leave behind."
]
]
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