title: Different data types in swift 3
body: <p>I understand different data types in programming and i understand that when we say var name = "John" , that means name is a variable of type string and holds the value "John", what i am struggling with is when we specify the type of the variable as a class like so: </p>
  
  <pre><code>    Class MyClass {
           //methods and properties
      }
     var class : MyClass
  </code></pre>
  
  <p>what is the value that the variable "class" is holding or can hold in the above line of code?!!</p>