segue.swift

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, UITextFieldDelegate, CLLocationManagerDelegate, MKMapViewDelegate {
    
    // reference the user input field
    @IBOutlet weak var inputText: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        inputText.delegate = self
    }
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        // Hide the keyboard.
        textField.resignFirstResponder()
        return true
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
        
        
    }
    
    @IBAction func unwindToMenu(segue: UIStoryboardSegue) {}
    
    // pass the value of the input throught the segue
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "showSecondViewController" {
            let secondViewController = segue.destination as? SecondViewController
            secondViewController?.userText = inputText.text
        }
    }

}