title: Change what print(Object) displays in Swift 2.0
body: <p>I am trying to make my class <code>Digit</code> display the <code>num</code> variable whenever print is called on that object, in Swift 2.0. I thought this might be done with a description variable, but no luck.</p>
  
  <pre><code>class Digit {
  
    var num: Int
    var x: Int
    var y: Int
    var box: Int
    var hintList: [Int] = []
    var guess: Bool = false
  
    var description: String {
      let string = String(num)
      return string
    }
  }
  </code></pre>