You would use it when you need a class that could be used in different
ways. For instance try creating a ‘Person’ interface and then implement that
interface in a class called ‘Man’ – implement another class the ‘Person’
interface and call this class ‘Women’ – Now both the ‘Man’ & ‘Women’ Classes
derive there members from the Person interface. The ‘Man’ is a ‘Person’ and
the ‘Women’ is a person. If we had created just two classes called ‘Man’ and
‘Women’ then they would have no connection and would also use most of the
same member names, even with the same logic. In a real time application you
would use it exactly the same way – You will need to plan your project with
polymorpism in mind, compare types, do they implement many of the same
features?