Which type inheritance objective c support?

Ans : Objective-C supports multi-level and hierarchical inheritance.

How many times Viewdidload and viewDidLayoutSubviews called?

Ans : 

ViewDidLoad called once only when all views are loaded.

viewDidLayoutSubviews :  Apple gave a very good explanation on this by saying that it is called to notify the view controller that its view has just laid out its subviews.

In another word, viewDidLayoutSubviews is called every time the view is updated, rotated or changed or it’s bounds change.

But know that with viewDidLayoutSubviews, it only take places after all the auto layout or auto resizing calculations on the views have been applied. Meaning the method viewDidLayoutSubviews is called every time the view size changes and the view layout has been recalculated.

Read More : AppCoda

Which method will first called if I came from back button?

Ans : 

The navigation controller sends viewWillAppear: to a view controller before putting its view on the screen, and viewDidAppear: after.

Inside viewWillAppear: and viewDidAppear:, the view controller can check self.isMovingToParentViewController.

If isMovingToParentViewController is YES, the view controller is being added to the navigation controller in the first place (presumably because it's the navigation controller's root view controller, or because it is being pushed).

If isMovingToParentViewController is NO, the view controller is already in the navigation controller's stack, and another view controller is being popped to reveal it.

How can we store object in user default?

Ans : 

Actually, you will need to archive the custom object into NSData then save it to user defaults and retrieve it from user defaults and unarchive it again. You can archive it like this

let teams = [Team(id: 1, name: "team1", shortname: "t1"), Team(id: 2, name: "team2", shortname: "t2")]

var userDefaults = UserDefaults.standard
let encodedData: Data = NSKeyedArchiver.archivedData(withRootObject: teams)
userDefaults.set(encodedData, forKey: "teams")
userDefaults.synchronize()

and unarchive it like this

let decoded  = userDefaults.data(forKey: "teams")
let decodedTeams = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! [Team]

But if you just did that you will get

.Team encodeWithCoder:]: unrecognized selector sent to instance

You will have to make Team conform to NSCoding just like this

class Team: NSObject, NSCoding {
    var id: Int
    var name: String
    var shortname: String


    init(id: Int, name: String, shortname: String) {
        self.id = id
        self.name = name
        self.shortname = shortname

    }

    required convenience init(coder aDecoder: NSCoder) {
        let id = aDecoder.decodeInteger(forKey: "id")
        let name = aDecoder.decodeObject(forKey: "name") as! String
        let shortname = aDecoder.decodeObject(forKey: "shortname") as! String
        self.init(id: id, name: name, shortname: shortname)
    }

    func encode(with aCoder: NSCoder) {
        aCoder.encode(id, forKey: "id")
        aCoder.encode(name, forKey: "name")
        aCoder.encode(shortname, forKey: "shortname")
    } 

}

Difference between network location and gps location.

Ans : 

Network location usually refers to cellular location, or wifi location. They are less accurate then GPS (Global Positioning System - satellite based) location. When the app cannot obtain GPS location (probably because the target device is inside a building), the less accurate network location is obtained and uploaded to the map page.