It is generally accepted / normal to declare instances of a global class in Swift / iOS

Question

I recently watched a video tutorial on Lynda.com, and I noticed that the author declared several global variables that included two instances of the class. The main reason for my question is because I heard that we need to try to avoid using global variables if you really don't need them. I can see the use of global variables for NSUserDefaults' Keys, but I'm not sure about global instances.

Here is the code showing global variable declarations. I am only concerned about variables masterViewand detailViewController.

import UIKit

var objects:[String] = [String]()
var currentIndex:Int = 0

var masterView:MasterViewController?
var detailViewController:DetailViewController?

let kNotes:String = "notes"
let BLANK_NOTE:String = "(New Note)"

class MasterViewController: UITableViewController {

     // class code 

}

Is it possible to declare class instances as global variables?

Answer 1

, Swift , " " - . , .

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var objects:[String] = [String]()
var currentIndex:Int = 0

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var masterView:MasterViewController?
var detailViewController:DetailViewController?

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Answer 2

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