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An orderly hierarchy

The C# inheritance mechanism allows you build an orderly hierarchy of classes to supplement the classes that are already in the class library.

When several of your abstract data types have characteristics in common, you can design their commonalities into a single superclass and separate theirunique characteristics into unique subclasses. This is one of the purposes of inheritance.

The airship hierarchy

For example, suppose you are building a program dealing with airships. All airships have altitude and range properties in common. Therefore, you couldbuild a base Airship class containing data and methods having to do with range and altitude.

From this superclass, you could derive a Balloon class and an Airplane class.

The Balloon class

The Balloon class might add properties and methods dealing with passenger capacity and what makes it go up (helium, hydrogen, or hot air) . Objects of the Balloon class would then be able to deal with altitude, range, passenger capacity, and what makes it go up.

The Airplane class

The Airplane class might add properties and methods dealing with engine type (jet or propeller) and cargo capacity. Objects of the Airplane class could then deal with altitude, range, engine type, and cargo capacity.

Three types of objects

Having created this hierarchy of classes, you could instantiate objects of type Airship , Balloon , and Airplane with the objects of each type having properties and methods to deal with those specialcharacteristics of the flying machine indicated by the name of the class.

From the general to the specialized

You may have noticed that in this hierarchical class structure, inheritance causes the structure to grow in a direction from most general to morespecialized. This is typical.

Single and multiple inheritance

C++ and some other object-oriented programming languages allow for multiple inheritance. This means that a new class can extend more than one superclass.This has advantages in some cases, but can lead to difficulties in other cases.

C# does not support multiple inheritance. Instead it supports a different mechanism called an interface that provides most of the benefits ofmultiple inheritance without most of the problems. I will explain the C# interface in a future module.

The ISA relationship

You will sometimes hear people speak of the ISA relationship when discussing OOP (such as in he is a hero) . The source of this terminology is more fundamental than you may at first suspect.

Object-oriented designers often strive to use inheritance to model relationships where a subclass "is a kind of" the superclass. For example, a car "is a kind of" vehicle. A programmer "is a kind of" employee which in turn "is a kind of" person. An airplane "is a kind of" airship and so is a hot-air balloon.

This relationship is called the ISA relationship. It's that simple.

The HASA relationship

If you were to define a class that more fully represents an airplane, you might choose to break certain parts of the airplane out into separate objectsand to incorporate them by reference into your Airplane class.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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