Save textfield's string in an array - Swift - arrays

Question

I am creating an application that, written a string in a textfield, saves it in an array. The array is showed in a tableViewController embedded in the mainViewController. The situation is the following.
http://i.stack.imgur.com/z5uTc.png.
I want that every time I tap the green "Save" button, the string I wrote in the textField is saved and showed in the tableView and the textField returns empty, so I can re-write a string, that is added in the array. The tableView, in this case, shows the two strings, I wrote in the same textField. I tried to write the code for the two viewControllers (the mainViewVC and the tableVC).
MainVC
import UIKit
class mainVC: UIViewController {
#IBOutlet var txtField: UITextField!
var embTableVC: tableVC!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "embededTableVC" {
embTableVC = segue.destinationViewController as! tableVC
}
}
#IBAction func Save() {
if let Text = txtField.text {
if txtField.text == "" {
myArray.append(Text)
let row = myArray.count-1
let indexPath = NSIndexPath(forRow: row, inSection: 0)
embTableVC.myTableView.insertRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
}
}
txtField.text = ""
txtField.resignFirstResponder()
}
}
TableVC
import UIKit
var myArray = [String]()
class tableVC: UITableViewController {
#IBOutlet var myTableView: UITableView! {
didSet {
myTableView.dataSource = self
myTableView.delegate = self
}
}
override func viewDidLoad() {
super.viewDidLoad()
myTableView.dataSource = self
myTableView.delegate = self
myTableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "customcell")
// Do any additional setup after loading the view, typically from a nib.
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
myTableView.reloadData()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return myArray.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = myTableView.dequeueReusableCellWithIdentifier("customcell", forIndexPath: indexPath) as UITableViewCell
cell.textLabel?.text = myArray[indexPath.item]
return cell
}
The code I wrote doesn't work. I can compile and run the application on my device, but when I tap the green "Save" button, the app crashes. The error message is "fatal error: unexpectedly found nil while unwrapping an optional value" on the line: embTableVC.myTableView.insertRowsAtIndexPaths([indexPath], withRowAnimation: .Fade) in the "Save" IBAction.
Can you help me?
Thanks a lot:)