Gabbrolee/dayFour.swift

## dayFour.swift
// struct and classes have their own method and its called properties
// two kind of properties observer and it is willset and didset
//willset provides a new value for the properties
//Didset gives old value
import UIKit
struct Person {
  var clothes: String {
    willSet {
      updateUI(msg: "I'm changing from \(clothes) to \(newValue)")
    }
    didSet {
      updateUI(msg: "I just change from \(oldValue) to \(clothes)")
    }
  }
  func updateUI(msg: String){
    print(msg)
  }
}
var taylor = Person(clothes: "T-shirts")
taylor.clothes = "short skirts"

// computed properties
struct Person1{
  var age: Int
  var ageInDogYears: Int {
    get {
      return age * 7
    }
  }

}
var fan = Person1(age: 25)
print(fan.ageInDogYears)


//MARKS:- STATIC PROPERTIES AND METHODS
// swift allow one to create property
//that belong to a type
// it use the keyword static

struct TaylorFan {
  static var favoriteSong = "Look What You Made Me Do"

  var name: String
  var age: Int
}
let fan1 = TaylorFan(name: "James", age: 25 )
print(TaylorFan.favoriteSong)

//MARKS:-ACCESS CONTROL
 //let one specify code inside struct and classes
//that need to be expose or not  to the outside world
// private propety means only swift code in same file
//as a type can read the property or its extensions
//code within the file can be access
//to make a property private you just write private
//public means everyone can read and write the property

class Person3{
private var name : String?
}

//MARKS:- POLYMORPHISM AND TYPECASTING

class Album {
  var name: String
  init(name: String){
    self.name = name
  }

  func getPerformance() -> String{
    return "The album \(name) sold lots"
  }
}

class StudioAlbum: Album {
  var studio: String

  init(name:String, studio: String){
    self.studio = studio
    super.init(name: name)
  }

  override func getPerformance() -> String {
    return "The album \(name) sold lots"
  }
}

class LiveAlbum: Album {
  var location: String

  init(name: String, location: String){
    self.location = location
    super.init(name: name)
  }

  override func getPerformance() -> String {
    return "The album \(name) sold lots"
  }
}
var taylorSwift = StudioAlbum(name: "Taylor Swift", studio: "The Castles Studio")
var fearless = StudioAlbum(name: "Fearless", studio: "Aimeeland Studio")
var iTunesLive = LiveAlbum(name: "iTumes Live from SoHo", location: "New York")
var allAlbums: [Album] = [taylorSwift, fearless, iTunesLive]

for album in allAlbums {
  print(album.getPerformance())
  if let studioAlbum = album as? StudioAlbum{             // typecasting
    print(studioAlbum.studio)

    if let liveAlbum = album as? LiveAlbum{             // typecasting
      print(liveAlbum.location)

    }

  }
}


// the Album class serve as a single interface to the subclasses without
//the subclasses losing their original class at the same time .

//MARKS:-TYPE CASTING
//This is a scenario of converting an object of one type to another
//optional down casting (?) this is use when not sure of conversion
//force down casting (!) this is when one is certain of conversion
// when it is force down casted and it is not true then app can crash


//MARKS;- CLOSURE
// closure are use to hold lines of swift code
// the copy of values use inside them can be taken
// below is a cocoa touch example

let vw = UIView()
UIView.animate(withDuration: 0.5, animations:{ vw.alpha = 0
})

// the UIView use the animate property inside it to set duration to
// 5seconds and use the closure animations to set opacity (alpha)
// to zero then continue doing that after interval of 5secs

UIView.animate(withDuration: 0.5) {
  vw.alpha = 0
}
// above is a trailing closure, it express the code in a shorter
// and neater way
	// struct and classes have their own method and its called properties
	// two kind of properties observer and it is willset and didset
	//willset provides a new value for the properties
	//Didset gives old value
	import UIKit
	struct Person {
	var clothes: String {
	willSet {
	updateUI(msg: "I'm changing from \(clothes) to \(newValue)")
	}
	didSet {
	updateUI(msg: "I just change from \(oldValue) to \(clothes)")
	}
	}
	func updateUI(msg: String){
	print(msg)
	}
	}
	var taylor = Person(clothes: "T-shirts")
	taylor.clothes = "short skirts"

	// computed properties
	struct Person1{
	var age: Int
	var ageInDogYears: Int {
	get {
	return age * 7
	}
	}

	}
	var fan = Person1(age: 25)
	print(fan.ageInDogYears)


	//MARKS:- STATIC PROPERTIES AND METHODS
	// swift allow one to create property
	//that belong to a type
	// it use the keyword static

	struct TaylorFan {
	static var favoriteSong = "Look What You Made Me Do"

	var name: String
	var age: Int
	}
	let fan1 = TaylorFan(name: "James", age: 25 )
	print(TaylorFan.favoriteSong)

	//MARKS:-ACCESS CONTROL
	//let one specify code inside struct and classes
	//that need to be expose or not to the outside world
	// private propety means only swift code in same file
	//as a type can read the property or its extensions
	//code within the file can be access
	//to make a property private you just write private
	//public means everyone can read and write the property

	class Person3{
	private var name : String?
	}

	//MARKS:- POLYMORPHISM AND TYPECASTING

	class Album {
	var name: String
	init(name: String){
	self.name = name
	}

	func getPerformance() -> String{
	return "The album \(name) sold lots"
	}
	}

	class StudioAlbum: Album {
	var studio: String

	init(name:String, studio: String){
	self.studio = studio
	super.init(name: name)
	}

	override func getPerformance() -> String {
	return "The album \(name) sold lots"
	}
	}

	class LiveAlbum: Album {
	var location: String

	init(name: String, location: String){
	self.location = location
	super.init(name: name)
	}

	override func getPerformance() -> String {
	return "The album \(name) sold lots"
	}
	}
	var taylorSwift = StudioAlbum(name: "Taylor Swift", studio: "The Castles Studio")
	var fearless = StudioAlbum(name: "Fearless", studio: "Aimeeland Studio")
	var iTunesLive = LiveAlbum(name: "iTumes Live from SoHo", location: "New York")
	var allAlbums: [Album] = [taylorSwift, fearless, iTunesLive]

	for album in allAlbums {
	print(album.getPerformance())
	if let studioAlbum = album as? StudioAlbum{ // typecasting
	print(studioAlbum.studio)

	if let liveAlbum = album as? LiveAlbum{ // typecasting
	print(liveAlbum.location)

	}

	}
	}





	// the Album class serve as a single interface to the subclasses without
	//the subclasses losing their original class at the same time .

	//MARKS:-TYPE CASTING
	//This is a scenario of converting an object of one type to another
	//optional down casting (?) this is use when not sure of conversion
	//force down casting (!) this is when one is certain of conversion
	// when it is force down casted and it is not true then app can crash



	//MARKS;- CLOSURE
	// closure are use to hold lines of swift code
	// the copy of values use inside them can be taken
	// below is a cocoa touch example

	let vw = UIView()
	UIView.animate(withDuration: 0.5, animations:{ vw.alpha = 0
	})

	// the UIView use the animate property inside it to set duration to
	// 5seconds and use the closure animations to set opacity (alpha)
	// to zero then continue doing that after interval of 5secs

	UIView.animate(withDuration: 0.5) {
	vw.alpha = 0
	}
	// above is a trailing closure, it express the code in a shorter
	// and neater way