<< Chapter < Page Chapter >> Page >
These learning objects are for control structures in Java. Control structures change the dynamic flow of a program and include if, loop, and switch statements.

Learning objects for control statements

Concept Normally, statements in Java are executed sequentially in the order written in the source code. Control statements are used to modify the order of execution of statements. Most control statements are conditional ; that is, the next statement to be executed depends on the result of evaluatingan expression, usually, an expression that returns a boolean value of true or false.

These source code of these learning objects can be found in control.zip .

LO Topic Java Files (.java) Prerequisites
"If-statements" If-statements Control01
"Conditional expressions" Conditional expressions Control02 1
"While loops" While loops Control03
"Do-while loops" Do-while loops Control04
"Break statements" Break statements Control05 3
"Counting with for statements" Counting with for statements Control06
"General for statements" General for statements Control07 6
"Continue statements" Continue statements Control08 6
"Switch statements" Switch statements Control09


Concept The execution of an if-statement starts with the evaluation of its boolean-valued expression. If the result is true, the statement writtenafter the closing parenthesis of the expression is executed; if the result is false, the statement written after the else is executed. These statements can be single statements or blocks of statements. In particular,the statements can themselves be if-statements ( nested if-statements ), in which case the inner statement is executed the same way.

Program: Control01.java

// Learning Object Control01 //    if statementspublic class Control01 {     public static void main(/*String[] args*/) {         int year = 2000;        int month = 6;         int days;        if (month == 2)             if (year % 4 == 0)                days = 28;             else                days = 29;         else if (month == 4 || month == 6 ||                month == 9 || month == 11)             days = 30;        else             days = 31;        System.out.println(days);     }}

The program computes the number of days in a month taking leap years into account.

  • The variables are allocated and the first two, year and month , are given initial values.
  • The expression month == 2 evaluates to false, so the statement following the else is executed. Jeliot will display Choosing else-branch to emphasize this.
  • The inner statement is itself an if-statement. The expression is evaluated and its result is true. Note that once one of the terms of || (or) becomes true, there is no need to evaluate the others.
  • The assignment statement following the statement is executed. Jeliot will display Choosing then-branch . (The terminology then-branch orginates from programming languages that require the use of the keyword then between the expression and the statement.)
  • The value of days is printed.

Exercise Complete the program with the correct computation for leap years: a year divisible by 100 is not a leap year unless itis also divisible by 400.

Questions & Answers

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
Do somebody tell me a best nano engineering book for beginners?
s. Reply
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?
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
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
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
what is system testing
what is the application of nanotechnology?
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
anybody can imagine what will be happen after 100 years from now in nano tech world
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
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Learning objects for java (with jeliot). OpenStax CNX. Dec 28, 2009 Download for free at http://cnx.org/content/col10915/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Learning objects for java (with jeliot)' conversation and receive update notifications?