Delegation in VCs

CurrencyPickerTableViewController.swift

protocol CurrencyPickerProtocol : class {
  	func selected(currency: String, from: CurrencyPickerTableViewController)
}

class CurrencyPickerTableViewController: UITableViewController {

    weak var delegate: CurrencyPickerProtocol
  
    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
            let key = order[indexPath.row]
            delegate.selected(currency: key, from: self)
    }
}