In Swift, an enumeration defines a common type for related values and enables us to work with those values in a type-safe way. Values provided for each enumeration member can be a String, Character, Integer, or any floating-point type.
The following example presents a simple definition of an enum:
enum MLSTeam { 
    case montreal 
    case toronto 
    case newYork 
    case columbus 
    case losAngeles 
    case seattle 
} 
let theTeam = MLSTeam.montreal 
enum MLSTeam provides options for MLS teams. We can choose only one of the options each time; in our example, montreal is chosen.
Multiple cases can be defined and separated by a comma on a single line:
enum MLSTeam { 
    case montreal, toronto, newYork, columbus, lA, seattle 
} 
var theTeam = MLSTeam.montreal 
The type of theTeam is inferred when it is initialized with MLSTeam.montreal. As theTeam is already defined, we can change it...