title: Make Quiz App Not Repeat Random Questions
body: <p>I know that there are some solutions with shuffle, or something like that, but I dont know if I can apply them in my code. Can you please help me? How do I make the questions not repeat?</p>
  
  <pre><code>func RandomQuestions(){
  
      var RandomNumber = arc4random() % 28
      RandomNumber += 1
  
      switch(RandomNumber){
      case 1:
          QuestionLabel.text = "Who is the Numer One Best DJ According to DJ Mag 2014?"
          Button1.setTitle("Tiësto", forState: UIControlState.Normal)
          Button2.setTitle("Avicii", forState: UIControlState.Normal)
          Button3.setTitle("Hardwell", forState: UIControlState.Normal)
          Button4.setTitle("Dimitri Vegas &amp; Like Mike", forState: UIControlState.Normal)
          CorrectAnwser = "3"
          break
      case 2:
          QuestionLabel.text = "Who is the Only DJ that played in an Olimpic Games?"
          Button1.setTitle("Avicii", forState: UIControlState.Normal)
          Button2.setTitle("Tiësto", forState: UIControlState.Normal)
          Button3.setTitle("Armin Van Buuren", forState: UIControlState.Normal)
          Button4.setTitle("Calvin Harris", forState: UIControlState.Normal)
          CorrectAnwser = "2"
          break
      }
  
      /* ...more questions...* /
  
  }
  </code></pre>