option selectable value (i)

: Playground-noun:a place where people can play

Import Cocoa

class person {

var residence:residence? // Optional Connection

}

class Residence {

var rooms = [guest] ()

var numberofrooms:Int {

return rooms. Count

}

subscript(i:Int) ,

return Rooms I

}

func printnumberofrooms () {

println("The number of rooms is\(numberofrooms)")

}

var address:address?

}

class The hostel {

let name:String

Init (Name:String) {

Self. name = Name

}

}

class Address {

var buildingname:String?

var buildingnubmer:String?

var street:String?

func buildingidentifier (),String? {

if (buildingname ! =Nil) {

return Buildingname

}Elseif (buildingnubmer ! =Nil) {

returnBuildingnubmer

}Else {

return Nil

}

}

}

Let John =person ()

Let Johnshouse = Residence ()

Johnshouse.rooms[0] = Guest (name: "Living")

John.residence = Johnshouse

/*

You can join multi-layer alternative links to dig up The lower-level attribute methods and corner labels within the model. However, multi-tier alternative links can no longer add more layers than are returned to the selected value. This means :

If you try to obtain a type that is not an alternative type , because of the optional link it becomes the optional type. If the type you are trying to obtain is already an alternative type , it will not increase the availability because of the optional link. therefore :

If you try to get an int value by an optional link, no matter how many layers of links are used , the int is always returned ?. similarly , if you are trying to get an Int through an optional link ? Value , regardless of how many layer links are used to return the always Int?.

*/

Let johnsaddress =Address()

Johnsaddress. Buildingname ="the"

Johnsaddress. Street ="Laurel"

John. Residence!. Address =johnsaddress

// link the method of the return value for the selection

If let Buildingidentifier = John.residence?. Address?. Buildingidentifier ()?. uppercasestring {

println ("John ' s building identifier is \ (Buildingidentifier).")

//}

// connect multi-layer links

If let Johnsstreet = John.residence?. Address?. Street {

println ("John ' s street name is \ (johnsstreet).")

} else {

println ("Unable to retrieve the address.")

//}

// Use the optional link to call the corner label

If let Firstroomname = John.residence? [0].name {

println ("The first guest name is \ (firstroomname).")

} else {

println ("Unable to retrieve the first")

//}

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option selectable value (i)