How do I open a alertcontroller from a button in tableview cell in ios 9?
<p>I want to open an Alertview with Call button and cancel button from button in a tableview cell.</p>

<pre><code>var arrayOfUsernames: [PFObject] = [ ]

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
    return arrayOfUsers.count
}

func numberOfSectionsInTableView(tableView: UITableView) -&gt; Int{
    return 1
}

func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -&gt; String? {
    return "Tutors"
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell
{
    let cell: CustomTableViewCell = TutorTable.dequeueReusableCellWithIdentifier("Tutor") as! CustomTableViewCell

    cell.CUsername.text = self.arrayOfUsers[indexPath.row]
    cell.Classes.text = self.arrayOfClasses[indexPath.row]
    return cell

}
</code></pre>

<p>here is the customtableviewcell</p>

<pre><code>import UIKit

class CustomTableViewCell: UITableViewCell {

    @IBOutlet weak var CUsername: UILabel!
    @IBOutlet weak var Distance: UILabel!
    @IBOutlet weak var Classes: UILabel!
    @IBOutlet weak var Rating: UIImageView!

    @IBAction func bookNow(sender: AnyObject) {
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}
</code></pre>