Sets are not terribly commonplace in development, but each of the languages we are examining supports data structures with some form of concrete implementations. Here are some examples of initializing a set, adding a few values to the collection including one duplicate, and printing the set's count to the console after each step.

C#

C# provides a concrete implementation of the set data structure through the HashSet<T> class. Since this class is generic, the caller may define the type used for elements. For example, the following example initializes a new set where the elements will be string types:

    HashSet<string, int> mySet = new HashSet<string>(); 
    mySet.Add("green");  
    Console.WriteLine("{0}", mySet.Count); 
    mySet.Add("yellow");  
    Console.WriteLine("{0}", mySet.Count); 
    mySet.Add("red");  
    Console.WriteLine("{0}", mySet.Count); 
    mySet.Add("red");  
    Console.WriteLine("{0}", mySet...