HashSet Class

Namespace: System.Collections.Generic

 A set is a collection that contains no duplicate elements, and whose elements are in no particular order.

A HashSet<T> object's capacity automatically increases as elements are added to the object.

The HashSet<T> class is based on the model of mathematical sets and provides high-performance set operations similar to accessing the keys of -->

-->the Dictionary <TKey,TValue> or Hashtable collections.

the HashSet<T> class can be thought of as a Dictionary<TKey,TValue> collection without values.

A HashSet<T> collection is not sorted.