back endless in iOS

 import UIKit

class ViewController: UIViewController {

    let APPLICATION_ID = "6426340C-029F-93DE-FF13-386286CFE300"
    let API_KEY = "55C445E1-281F-988F-FFCE-F26A462A8C00"
    let SERVER_URL = "https://api.backendless.com"
    let backendless = Backendless.sharedInstance()!

    override func viewDidLoad() {
        super.viewDidLoad()
        // first instateation of backendless
        backendless.hostURL = SERVER_URL
        backendless.initApp(APPLICATION_ID, apiKey: API_KEY)


        //sample for user registration
        //registerUser()
        loginUser()

    }

    func loginUser()
    {
        let backendless = Backendless.sharedInstance()!
        backendless.userService.login("oleg@hi.bye", password: "12345", response: {(logUser: BackendlessUser?) -> Void in
            print ("user logged in!!!")
            self.writeData()
        },
            error: {(fault: Fault?) -> Void in
            print ("server reported an error:\((fault?.description))")
        })
    }

    func writeData()
    {
        //saving some tasks to test table
        let testObject=["MyTask":"Silin will marry Firas"]
        let dataStore = backendless.data.ofTable("TestTable")
        dataStore?.save(testObject,
                        response: {(res) -> Void in
                            print ("object is saved.")
        },
                        error: {(fault:Fault?) -> Void in
                            print ("server reported an error:\(fault)")
        })
    }



    func registerUser()
    {
        let user = BackendlessUser()
        user.setProperty("email", object: "Oleg@hi.bye")
        user.password="12345"
        backendless.userService.register(user,
            response : {(regUser: BackendlessUser?)-> Void in
            print ("User registered \(regUser?.value(forKey: "email"))")
        },
            error: {(fault: Fault?) -> Void in
            print ("Server reported error: \(fault?.description)")
        })
    }

 /*
     // Saving test object in the test table
     let testObject = ["foo" : "bar"];
     let dataStore = backendless.data.ofTable("TestTable")
     dataStore?.save(testObject,
     response: {
     (result) -> () in
     print("Object is saved in Backendless. Please check in the console.")
     },
     error: {
     (fault : Fault?) -> () in
     print("Server reported an error: \(String(describing: fault))")
     })

  */

 }