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Figure 2 . Text output for overridden ToString method and class B.

ToString in class B

Do you recognize this?

You should recognize this as the text that was encapsulated in the String object returned by the overridden version of the ToString method defined in the class named B . (See Listing 2 .)

Overridden version of ToString was executed

This verifies that even though the reference to the object of the class B was stored in a reference variable of type Object , the overridden version of the ToString method in the class named B was executed (instead of the default version defined in the class named Object) . This is runtime polymorphic behavior , as described in a previous module.

Once again, what is the rule?

The selection of a method for execution is based on the actual type of object whose reference is stored in a reference variable, and not on the type of the reference variable on which the method is called.

An object of the class C

Finally, the code in Listing 6

  • Instantiates a new object of the class C
  • Stores the object's reference in a reference variable of type Object
  • Calls the ToString method on the reference and saves the returned string
  • Displays the returned string on the computer screen

Listing 6 . An object of the class C.

Object varC = new C(); String v3 = varC.ToString();Console.WriteLine(v3); //Pause until user presses any key.Console.ReadKey();}//end Main }//end class Polymorph04

What will the output look like?

By now, you should know what to expect in the way of text appearing on the computer screen. The code in Listing 6 causes the text shown in Figure 3 to be displayed.

Figure 3 . Text output for overridden ToString method and class C.

ToString in class C

Overridden version of ToString was called

This confirms what you should already have known by now. In particular, even though the reference to the object of the class C was stored in a reference variable of type Object , the overridden version of the ToString method defined in the class named C was executed. Again, this is runtime polymorphic behavior based on class inheritance and method overriding.

No downcasting was required

It is also very important to note that no downcasting was required in order to call the ToString method in any of the cases shown above.

Because a default version of the ToString method is defined in the Object class, that method can be called without a requirement for downcasting on a reference to any object stored in a variable oftype Object . This holds true for any of the methods defined in the class named Object .

A generic array object

Therefore, if we create an array object designed to store references of type Object , we can store (potentially mixed) references to any type of object in that array. We can later call any of the methods definedin the Object class on any of the references stored in the array.

The result will be the execution of the overridden version of the method as defined in the class from which the object was instantiated, or the versioninherited into that class if the method is not overridden in that class. Current jargon would say that the behavior of the method is appropriate for the type of object on which it is called.

Questions & Answers

how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
hii
Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Xna game studio. OpenStax CNX. Feb 28, 2014 Download for free at https://legacy.cnx.org/content/col11634/1.6
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