Define a restraunt "Lombardi's" that serves pizza with pesto, bacon, and cheddar cheese

struct Pizza { 
   let ingredients: [String] 
} 

protocol Pizzeria { 
   func makePizza(_ ingredients: [String]) -> Pizza 
      func makeMargherita() -> Pizza 
   } 
extension Pizzeria { 
   func makeMargherita() -> Pizza { 
      return makePizza(["tomato", "mozzarella"]) 
   } 
}

struct Lombardis: Pizzeria { 
   func makePizza(_ ingredients: [String]) -> Pizza { 
      return Pizza(ingredients: ingredients) 
   } 
   func makeMargherita() -> Pizza { 
      return makePizza(["tomato", "basil", "mozzarella"]) 
   } 
}


To call:
let lombardis: Pizzeria = Lombardis()

Why does this code throw a compile-time error?

struct Kitten {
}

func showKitten(kitten: Kitten?) {
   guard let k = kitten else {
      print("There is no kitten")
   } 
   print(k)
}

The else block of a guard requires an exit path, either by using return, throwing an exception or calling a @noreturn. 

1. func showKitten(kitten: Kitten?) {
   guard let k = kitten else {
      print("There is no kitten")
      return
   }
   print(k)
}

2. Instead of 'return', throw fatalError()

3. enum KittenError: Error {
   case NoKitten
}

struct Kitten {
}

func showKitten(kitten: Kitten?) throws {
   guard let k = kitten else {
      print("There is no kitten")
      throw KittenError.NoKitten
   }
   print(k)
}

try showKitten(kitten: nil)

What is unique about Sets?

aaaThey are an array of objects that are automatically unordered, and duplicates are ignored

What are Tuples?

Tuples are a type of variable that can store multiple values stored in a single value

var name = (first: "Taylor", last: "Swift")

What are Enumerations?

Enumerations are a way to define groups of related values to make them easier to use.

enum Result{

   case success

   case failure

}

let result = Result.failure

What are Enumeration associated values?

enum Activity{

   case bored

   case running(destination: String)

   case talking(topic: String)

}

let talking = Activity.running(destination: "Africa")

Write a function that takes a parameter Int, returns a String

Call it.

func format(number: Int) -> String{

   return "bla"

}

To call: 

let bla = format(number: 3)

Write a function that takes a parameter Int and returns a String. Use _

Call it.

func format(_ number: Int) -> String{

   return String(number)

}

To call:

let bla = format(3)

What are Inouts? 

Write a function that uses InOuts. 

Call the function.

Inouts are functions where you can change the parameter inside them.

func double(number: inout Int){

   number *= 2

}

To call:

var bla = 10

double(&10)

What are Closures?

Write a closure.

Call it

A closure is a function assigned to a variable

let driving = {

   print("bla")

}

To call:

driving()

What is a struct? 

Is it a reference type or a value type? What do each mean?

What is the difference between a struct and a class?

What do you call a function defined inside a struct? 

Write a struct Sport with a name property

Call it.

A struct is a data type that can store values, and can define functions. They can define initializers to set up their initial state with init()

A struct is a value type. When you copy a value type, each instance keeps a unique copy of the data. When you copy a reference type, each instance SHARES the data. When you change one, the other changes too. 

A class can create a subclass that will inherit the paren't properties and methods, whereas structs don't support inheritance. A class has all members private by default. A struct is a class where members are public by default. 

A function inside a struct is called a method.

struct Sport(){

   var name: String

}

var tennis = Sport(name: "tennis")

Remember that structs are value types, which means they are supposed to be immutable. 

Say we have a struct

struct Rectangle(){

   var width = 2

   var height = 2

}

Write a function inside the struct that doubles the width and height of the rectangle. 

struct Rectangle(){

   var width = 2

   var height = 2

   mutating func makeDouble(){

      width *= 2

      height *= 2

   }

}

What is a class? 

Is it a reference type or a value type? What do each mean?

What is the difference between a class and a struct?

Write a class Sport with a name property

Call it.

A class is a data type that can store values, and can define functions. They can define initializers to set up their initial state with init()

A class is a reference type. When you copy a reference type, each instance SHARES the data. When you change one, the other changes too. A struct is a value type. When you copy a value type, each instance keeps a unique copy of the data.  

A class can create a subclass that will inherit the paren't properties and methods, whereas structs don't support inheritance. A class has all members private by default. A struct is a class where members are public by default. 

class Sport(){

   var name: String

}

var tennis = Sport(name: "tennis")

Write a class Dog with properties name, age, with initial values of "Doberman" for name, "14" for age. 

Write function printWoof that prints "Woof".

}

class Dog{

   var name: String

   var age: Int

   init(){

      name = "Doberman"

      age = 14

   }

   func printWoof(){

      print("woof")

   }

}

Simplify a function that adds two values together using $0 and $1

var add = {(arg1: Int, arg2: Int) -> Int in

   return arg1 + arg2

}

var add = {(arg1: Int, arg2: Int) -> Int in

   return arg1 + arg2

}

add = {(arg1, arg2) -> Int in

   return arg1 + arg2

}

add = {

   $0 + $1

}

let result = add(20, 20)

Simplify a function that adds two values together using $0 and $1

var add = {(arg1: Int, arg2: Int) -> Int in

   return arg1 + arg2

}

var add = {(arg1: Int, arg2: Int) -> Int in

   return arg1 + arg2

}

add = {(arg1, arg2) -> Int in

   return arg1 + arg2

}

add = {

   $0 + $1

}

let result = add(20, 20)

It solves the problem of code duplication.