A Set is an abstract data type (ADT) that stores unique elements. It provides the following operations: a. void add(E element)- adds an element to the set. If the same element (according to equals(Object)) is already in the set, the new element is ignored . Note: this is different from how Maps work!

b. void remove(E element)- removes an element from the set.

c. boolean contains(E element)- returns true if the element is in the set, and false otherwise.

d. int size() - returns the number of elements stored in the set.

e. Iterator iterator() - returns an iterator that can be used to iterate over the elements in the set. This is necessary to enable a data structure to work with Java's for loops.

You can think of a Set like a Map that only stores keys (and no values). In fact, a Set can be implemented using a Map - the elements of the set are keys in the Map (the values in the Map do not matter and can be null or some other placeholder value).

Create a generic Set interface that provides the methods described above.