title: swift identify which button was pressed
body: <p>How to identify in swift if which button was pressed i have 3 button actions.now i have another button is which when pressed it will identify which button from the 3 was pressed. cause first is you have to click from the 3 button after clicking from the 3 button then you will click 
  idenfifywhichpressed button and this button will identify or print which button from the 3 was pressed.</p>
  
  <pre><code>//this button will identify
      @IBAction func idenfifywhichpressed(_ sender: UIButton) {
      }
  </code></pre>
  
  <p>the 3 buttons</p>
  
  <pre><code> @IBAction func btn1(_ sender: UIButton) {
  }
   @IBAction func btn2(_ sender: UIButton) {
  }
   @IBAction func btn3(_ sender: UIButton) {
  }
  </code></pre>