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As indicated in Figure 1 , the + operator is also used for string concatenation, but that is another topic for another lesson.

Are the operators as innocuous as they seem?

At first glance, you might ask why there is a need to elaborate on or to clarify thisspecification. After all, aren't the arithmetic operators completely innocuous? The fact is that the arithmetic operators may not be as innocuous as they seem.There are several pitfalls involving these operators that can trap the unsuspecting Java programming student.

The subtraction operator is rather innocuous

There is very little to say about the - operator. It performs numeric subtraction as indicated in Figure 1. It is hard to get into trouble doingnumeric subtraction.

The other operators are not so innocuous

However, the addition, multiplication, division and remainder operators probably do deserve a little more scrutiny, particularly insofar as to how they behave for different types. (Note that the remainder operator is also known as the modulus operator.)

Integer division

Let's begin with a question. Which of the following outputs, if any, is produced by the program shown in Listing 1 ?

  • A. Compiler Error
  • B. Runtime Error
  • C. 33.666666
  • D. 34
  • E. 33
Listing 1 . Integer division.
public class Division01{ public static void main(String args[]){ new Worker().doWork();}//end main() }//end class definitionclass Worker{ public void doWork(){int myVar01 = 101; int myVar02 = 3;System.out.println(myVar01/myVar02); }//end doWork()}//end class definition

The first program

Since this the first program code that I have presented in this series of lessons, I will explain some aspects of the code before providing and explainingthe answer to the question.

A violation of specification number 18

To begin with, this program, (and many of the other programs that I will present in this series of lessons) , violates specification number 18 in the course description . That specification reads partiallyas follows:

"18. Visibility: In the AP Java subset, all classes are public."

Overkill

While that probably is a worthwhile requirement in large-scale project development, it is overkill for the simple programs that I will present in thisseries of lessons. (Note that the class named Worker in Listing 1 is not declared public .)

If I were to declare the Worker class public , it would be necessary for me to put it in a separate disk file named Worker.java . That would complicate my disk management efforts with regard to this series of lessons, and would also complicate your efforts in those cases whereyou want to copy, compile, experiment with, and execute the code.

All class definitions in the same disk file

Therefore, in most cases, I will omit the public declaration for all classes other than the driver class that contains the main method. That will allow me to putall classes belonging to a single program in a single disk file, and to provide a listing of the program in a form that you can easily copy into your IDE.

Having copied the program into your Java IDE, you can save the source code in a single disk file. Having done that, you can compile andexecute the program without having to create a separate disk file for each class definition in the program.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Ap computer science a, clarification of the java subset. OpenStax CNX. Oct 03, 2015 Download for free at https://legacy.cnx.org/content/col11279/1.5
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