Unions, Nested Classes, Constructors & Destructors

C++ language permits the user to create an array of any data type involving user-defined data types. Therefore, an array of variables of a class data type could also be defined, and such variables are known as an array of objects. A Union can be used as a user defined data type whose size is enough to hold one of its members.  Such as control structures classes can also be nested. The idea of constructors or Destructors is also discussed.