Show viewController and pass data without storyboard and segue programming

Question

I want to pass firstVC data to secondVC.
But I don't know how to pass programming.

Class FirstVC: ViewController {

   var firstText: String = "hello"

   func goToSecondVC {
       var vc: SecondVC = SecondVC()
       vc.secondText = firstText
       self.show(vc, sender:nil)
   }

}

class SecondVC: ViewController {

var secondText: String = ""

    override func viewDidLoad() {

        print(secondText)
    }
}

I search in stack and find following answer.
Have another answer without storyboard,segue,delegate and NSUserDefaults? And this answer use the storyboard.

let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "newViewController") as! NewViewController

newViewController.stringVariable = stringVariable

self.present(newViewController, animated: true, completion: nil)

Answer 1

In First ViewController,

@IBAction func Some_Button(_ sender: Any) {
    let secndVC = self.storyboard?.instantiateViewController(withIdentifier: 
    "SecondViewControllerID") as! SecondViewController
    let someString = "this is my string" //Whatever You Want to pass.
    secndVC.SomeString=someString
    self.navigationController?.pushViewController(secndVC, animated: true)
}

In second ViewController, //Just Define String

var SomeString = ""
//that's it.

You Will Get Your Data in viewDidLoad

 override func viewDidLoad() {
    super.viewDidLoad()
    print(SomeString);
}

Answer 2

To do this you need to use custom init method.

class FirstVC: UIViewController {
    
    var firstText: String = "hello"
    
    func goToSecondVC() {
        let vc = SecondVC(text: firstText)
        self.navigationController?.pushViewController(vc, animated: true)
    }
    
}

class SecondVC: UIViewController {
    
    var secondText: String = ""
    
    init(text: String) {
        secondText = text
        super.init(nibName: nil, bundle: nil)
        
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        print(secondText)
    }
}