MVCについて

struct CountModel {
    var count: Int = 0
}

final class ThirdTableViewCell: UITableViewCell {

    @IBOutlet private weak var countLabel: UILabel!

    override func prepareForReuse() {
        super.prepareForReuse()

        countLabel.text = nil
    }

    func configure(countModel: Int) {
        countLabel.text = countModel.description
    }
}

import UIKit

final class InitialViewController: UIViewController {

    static func makeFromStoryboard() -> InitialViewController {
        let vc = UIStoryboard.initialViewController
        return vc
    }


    @IBAction private func showSecondButton(_ sender: Any) {
        Router.showSecond(vc: self)
    }
}

import UIKit

final class SecondViewController: UIViewController {

    var countModel = CountModel.init(count: 0)

    @IBOutlet private weak var countLabel: UILabel! {
        didSet{
            countLabel.text = countModel.count.description
        }
    }

    static func makeFromStoryboard() -> SecondViewController {
        let vc = UIStoryboard.secondViewController
        return vc
    }

    @IBAction private func countUpButton(_ sender: Any) {
        print("カウントされました")
        countModel.count += 1
        countLabel.text = countModel.count.description
    }

    @IBAction private func showThirdButton(_ sender: Any) {
        Router.showThird(vc: self, countModel: countModel)
    }

}

import UIKit

final class ThirdViewController: UIViewController {


    private let CELL_NIB_NAME = "ThirdTableViewCell"
    private let CELL_ID = "ThirdTableViewCell"

    var countModel: [CountModel] = []

    @IBOutlet private weak var tableView: UITableView! {
        didSet {
            let cellNIB = UINib(nibName: CELL_NIB_NAME, bundle: nil)
            tableView.register(cellNIB, forCellReuseIdentifier: CELL_ID)

            tableView.isHidden = true
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self

        tableView.isHidden = false
    }

    static func makeFromStoryboard(countModel: CountModel) -> ThirdViewController {
        let vc = UIStoryboard.thirdViewController
        vc.countModel.append(countModel)
        return vc
    }

}

extension ThirdViewController: UITableViewDelegate {

}

extension ThirdViewController: UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard
            let cell = tableView.dequeueReusableCell(withIdentifier: CELL_ID, for: indexPath) as? ThirdTableViewCell
        else {

            return UITableViewCell()
        }


        let count = countModel[indexPath.row].count

        cell.configure(countModel: count)


        return cell
    }


}

import UIKit

// Storyboardの読み込みを１箇所にまとめる
extension UIStoryboard {
  static var initialViewController: InitialViewController {
    UIStoryboard.init(name: "Initial", bundle: nil).instantiateInitialViewController() as! InitialViewController
  }

  static var secondViewController: SecondViewController {
    UIStoryboard.init(name: "Second", bundle: nil).instantiateInitialViewController() as! SecondViewController
  }

  static var thirdViewController: ThirdViewController {
    UIStoryboard.init(name: "Third", bundle: nil).instantiateInitialViewController() as! ThirdViewController
  }
}