You use the assignment operator (operator = ()) whenever an
existing object is to be replaced with a different object.
The copy constructor X(const X&) is used to create a new
instance of an X-object exactly like another.

Notice the subtle difference. Assignment changes an existing
object while construction creates a new object. You can view
assignment as the application of a destructor, to flush away
the existing object, followed by a copy construction, to
make an exact copy of the assigned object.

Copy Constructor means creation of new object and after that
copy properties of some exiting object to newly created object.

Overloading assignment operator is that copy properties of
some exiting object to another exiting object of same type.