[SOLVED] C html math swift Announcements

Announcements
Next Wednesday (Sept 4th) is our first Studio Day If you have a Mac laptop running Xcode 10.2.1 come to
Steinberg 105 during the normal class time (11:30 1 PM)
If you do not have a Mac laptop you will meet in Whitaker 316 either during class time or on Thursday
I will email out your Whitaker lab time based on the Google doc survey responses
If you have a Mac laptop
Install Xcode 10.2.1 before class
https://developer.apple.com/download/more/
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Todays Topics
Swift
Overview
Syntax
Examples
Xcode 10
Playgrounds
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Swift
New programming language developed by Apple
Announced at WWDC 2014
Interoperates with Objective-C
Both are considered first class citizens
We are using Swift version 5
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Hello World in Swift
print(Hello World)
No semicolons
No main method needed
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Variables and Constants
Swift uses var and let to describe variables and constants
Variables and constants have a type let languageName: String = Swift var version: Double = 1.0
let isEverChanging: Bool = true
Swift supports type inference
let languageName = Swift //inferred as String var version = 1.0 //inferred as Double
let isEverChanging = true //inferred as Bool
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Common Data Types in Swift
String
Character Int
Float
Double
Bool
Optional
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Strings
Swift makes working with strings easy let firstName = John
let lastName = Smith
let fullName = firstName + + lastName
Enumerating through them is familiar for character in firstName.characters{
print(character) }
J o h n
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String Interpolation
let a = 2, b = 3
// 2 times 3 is 6
let mathResult = (a) times (b) is (a * b)
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Collections Arrays and Dictionaries
var names = [Bob, Alice, Mike, Jen]
Inferred as a typed collection of Strings
I could also be more explicit:
var names: [String] = [Bob, Alice, Mike, Jen]
var numberOfLegs = [ant: 6, snake: 0, cow :4]
Inferred as a typed dictionary of Strings and Ints
Or I could be more explicit:
var numberOfLegs: [String: Int] = [ant: 6, snake: 0, cow :4]
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Collections Sets
A collection that stores distinct elements with no defined order var favoriteGenres: Set = [Rock, Classical, Hip hop]
var favoriteGenres: Set = [Rock, Classical, Hip hop]
Inferred as a set of type Set collection of Strings
print(I have (favoriteGenres.count) music generes.) //Prints I have 3 favorite music genres.
if favoriteGenres.isEmpty { print(Nothing here)
}
Add unique strings to the set favoriteGenres.insert(Jazz)
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Loops
while !done { keepDoingSomething()
}
for num in 15 {
//Prints from 1 up to and including 5
print((num) times 4 is (num * 4)) }
for num in 1..<5 {doSomething(i) }//Prints from 1 up to 411E-xCteSnEs4i3b8le MNoebtiwleoArpkpinlicgatPiolnatDfoevrmelopment 11 Conditionals if legCount == 0 { print(“Does not walk”)} else if legCount == 1 { print(“Hopping around”)} else {print(“I can walk”)}switch legCount { case 0:print(“Does not walk”)case 1, 3, 5, 7:print(“Limps around”)default:} print(“I can walk”)12E-xCteSnEs4i3b8le MNoebtiwleoArpkpinligcatPiolantDfoevrmelopment 12Functions func sayHi() { print(“Hi”)func sayHi(name: String = “CSE 438”) { } print(“Hi (name)!”)sayHi() //Prints Hi CSE 438}sayHi()func sayHi(name: String) { print(“Hi (name)!”)}sayHi(name: “Bob”)sayHi(name: “Bob”)//Prints Hi Bob13E-xCteSnEs4i3b8le MNoebtiwleoArpkpinligcatPiolantDfoevrmelopment 13 Functions func sayHi(name: String = “CSE 438”) -> String { } returnHi+name
let name = sayHi() //Name contains Hi CSE 438
func refreshWebSite() -> (Int, String ) { // refresh
return (200, Success)
} let (statusCode, message) =refreshWebSite()
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Closures
Self-contained blocks of functionality that can be passed around
let displayGreeting = { } print(Hello Class)
let displayGreeting: () -> () = {
print(Hello Class) }
displayGreeting()
//Inferred as this
//looks very similar to a function (named closure)
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Optionals
Optionalshandletheabsenceofavalue
There is a value and it equals x or there isnt a value
var numberOfLegs = [ant: 6, snake: 0, cow :4]
let possibleNumLegs = numberOfLegs[goat] ???
let possibleNumLegs: Int? = numberOfLegs[goat] //Value or nil
If possibleNumLegs != nil {
let legCount = possibleNumLegs! //Use ! to unwrap the optional
} print(Goat has (legCount) legs)
Shorthand for above, if let
If let legCount = possibleNumLegs { } print(Goathas(legCount)legs)
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Enumerations
A common type for a group of related values
Much more powerful than enumerations in the C language
Allows for associated values of ANY type (not just integer values)
enum CompassPoint { case north
case south
case east
case west }
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Enumerations
enum CompassPoint { case north
case south
case east
case west }
var directionToHead = CompassPoint.west directionToHead = .south
switch directionToHead { case .north:
print(Lots of planets have a north) case .south:
print(Watch out for penguins) case .east:
print(Where the sun rises) case .west:
print(Where the skies are blue) }
// Prints Watch out for penguins
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Classes and Structures (structs)
General purpose constructs which are the building blocks of your code
You define methods and properties to add functionality
Classes have additional capabilities that structs do not
Inheritance enables one class to inherit characteristics of another
Type casting allows you to treat an instance as a superclass or subclass from their class hierarchy
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Classes
class Person {
var age = 21 //defines the properties
var description: String { //defines a computed property get {
return You are (age) years old }
} }
let somePerson = Person()
print(Hello, you are (somePerson.age) years old)
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Properties
Associated values with a particular class, struct, or enum Properties are either stored or computed
Stored properties are constants and variables associated with an instance
Notavailableinanenum
Computed properties are calculated
struct FixedLengthRange { var firstValue: Int
let length: Int }
var rangeOfThreeItems = FixedLengthRange(firstValue: 0, length: 3) // the range represents integer values 0, 1, and 2
rangeOfThreeItems.firstValue = 6
// the range now represents integer values 6, 7, and 8
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Extensions
Adds new functionality to an existing structure, class, enumeration or protocol
Extensions support the following features: Add computed instance and type properties Specify instance and type methods
Make existing type conform to a protocol
Extensions may add new functionality to a type, but are unable to override existing functionality
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Extensions
extension Double {
var km: Double { return self * 1_000.0 } var m: Double { return self }
var cm: Double { return self / 100.0 } var mm: Double { return self / 1_000.0 } var ft: Double { return self / 3.28084 }
}
print(One inch is (oneInch) meters) // Prints One inch is 0.0254 meters
let threeFeet = 3.ft
print(Three feet is (threeFeet) meters)
// Prints Three feet is 0.914399970739201 meters
let oneInch = 25.4.mm
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More Information about Swift Language
Official Swift Programming Guide
https://docs.swift.org/swift-book/index.html
WWDC 2016 2019 Videos developer.apple.com
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Examples in Playground
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