Programing IN C++
What is
polymorphism?
Polymorphism refers to the ability of an object to respond
in a logically identical fashion to messages of the same protocol, containing
differing types of objects. Consider 1 + 5 and 1 + 5.1. In the former, the
message “+ 5″ is sent to an object of class integer (1). In the later, the
message “+ 5.1″ is sent to the same integer object. The form of the message
(its protocol) is identical in both cases. What differs is the type of object
on the right-hand side of these messages. The former is an integer object (5)
while the later is a floating point object (5.1). The receiver (1) appears (to
other objects) to respond in the same way to both messages. Internally,
however, it knows that it must treat the two types of objects differently in
order to obtain the same overall response.
Polymorphism refers to the ability to have more than one
method with the same signature in an inheritance hierarchy. The correct method
is invoked at run-time based on the context (object) on which the method is
invoked. Polymorphism allows for a generic use of method names while providing
specialized implementations for them.
What are
instance variables?
These represent an object’s private memory. They are defined
in an object’s class.
What are class
variables?
These represent a class’s memory which it shares with each
of its instances.
What is a
method?
A method is a class’s procedural response to a given message
protocol. It is like the definition of a procedure in other languages.
In C++ what is
a constructor? A destructor?
A constructors and destructors are methods defined in a
class that are invoked automatically when an object is created or destroyed. They
are used to initialize a newly allocated object and to cleanup behind an object
about to be removed.