<< Chapter < Page Chapter >> Page >

What output is produced by the program shown in Listing 1 (select one or more answers) ?

  • A. Compiler Error
  • B. Runtime Error
  • C. Joe Bill Tom JOE BILL TOM
  • D. BILL Bill JOE Joe TOM Tom
  • E. TOM BILL JOE Tom Bill Joe
  • F. Joe Bill Tom JOE TOM BILL
  • G. Tom TOM Joe JOE Bill BILL
  • H. Joe Bill Tom
  • I. None of the above.
Listing 1 . The program named Comparator07 .
//File Comparator07.java //Copyright 2001, R.G.Baldwinimport java.util.*; public class Comparator07{public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Comparator07 class Worker{public void doIt(){ Iterator iter;Collection ref; ref = new ArrayList();Populator.fillIt(ref); iter = ref.iterator();while(iter.hasNext()){ System.out.print(iter.next() + " ");}//end while loop System.out.println();Collections.reverse((List)ref); iter = ref.iterator();while(iter.hasNext()){ System.out.print(iter.next() + " ");}//end while loop System.out.println();Comparator aComparator= Collections.reverseOrder(); Collections.sort((List)ref, aComparator);iter = ref.iterator(); while(iter.hasNext()){System.out.print(iter.next() + " "); }//end while loopSystem.out.println(); }//end doIt()}// end class Worker class Populator{public static void fillIt(Collection ref){ ref.add("Joe");ref.add("Bill"); ref.add("Tom");ref.add("JOE"); ref.add("BILL");ref.add("TOM"); }//end fillIt()}//end class Populator

And the answer is ...

The correct answer to the above question is C, E, and G. The output from the program is shown below:

Joe Bill Tom JOE BILL TOM TOM BILL JOE Tom Bill JoeTom TOM Joe JOE Bill BILL

If that was your answer, you probably already understand most of the material covered in this module. In that case, you might consider skipping thismodule and moving on to the next module. If that wasn't your answer, you should probably continue with your study of this module.

Similar to previous programs

The overall structure of this program in Listing 1 is similar to programs that I have discussed in previous modules. Therefore, I will concentrateon those aspects of this program that differentiate it from the programs in previous modules.

A new ArrayList object

The code in Listing 2 instantiates a new ArrayList object and passes that object's reference to a method named fillIt where it ispopulated with the names of several people.

Listing 2 . A new ArrayList object.
ref = new ArrayList(); Populator.fillIt(ref);iter = ref.iterator();while(iter.hasNext()){ System.out.print(iter.next() + " ");}//end while loop

Displays the list contents

The code in Listing 2 also gets an iterator on the list and uses that iterator to display the contents of the populated list. At that point inthe program, the list contains the following elements in the order shown:

Joe Bill Tom JOE BILL TOM

You will recognize this as matching the order in which the elements were added to the list by the fillIt method shown in Listing 3 .

Listing 3 . The fillIt method.
class Populator{ public static void fillIt(Collection ref){ref.add("Joe"); ref.add("Bill");ref.add("Tom"); ref.add("JOE");ref.add("BILL"); ref.add("TOM");}//end fillIt() }//end class Populator

Questions & Answers

what is mutation
Janga Reply
what is a cell
Sifune Reply
how is urine form
Sifune
what is antagonism?
mahase Reply
classification of plants, gymnosperm features.
Linsy Reply
what is the features of gymnosperm
Linsy
how many types of solid did we have
Samuel Reply
what is an ionic bond
Samuel
What is Atoms
Daprince Reply
what is fallopian tube
Merolyn
what is bladder
Merolyn
what's bulbourethral gland
Eduek Reply
urine is formed in the nephron of the renal medulla in the kidney. It starts from filtration, then selective reabsorption and finally secretion
onuoha Reply
State the evolution relation and relevance between endoplasmic reticulum and cytoskeleton as it relates to cell.
Jeremiah
what is heart
Konadu Reply
how is urine formed in human
Konadu
how is urine formed in human
Rahma
what is the diference between a cavity and a canal
Pelagie Reply
what is the causative agent of malaria
Diamond
malaria is caused by an insect called mosquito.
Naomi
Malaria is cause by female anopheles mosquito
Isaac
Malaria is caused by plasmodium Female anopheles mosquitoe is d carrier
Olalekan
a canal is more needed in a root but a cavity is a bad effect
Commander
what are pathogens
Don Reply
In biology, a pathogen (Greek: πάθος pathos "suffering", "passion" and -γενής -genēs "producer of") in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s.[1][2
Zainab
A virus
Commander
Definition of respiration
Muhsin Reply
respiration is the process in which we breath in oxygen and breath out carbon dioxide
Achor
how are lungs work
Commander
where does digestion begins
Achiri Reply
in the mouth
EZEKIEL
what are the functions of follicle stimulating harmones?
Rashima Reply
stimulates the follicle to release the mature ovum into the oviduct
Davonte
what are the functions of Endocrine and pituitary gland
Chinaza
endocrine secrete hormone and regulate body process
Achor
while pituitary gland is an example of endocrine system and it's found in the Brain
Achor
what's biology?
Egbodo Reply
Biology is the study of living organisms, divided into many specialized field that cover their morphology, physiology,anatomy, behaviour,origin and distribution.
Lisah
biology is the study of life.
Alfreda
Biology is the study of how living organisms live and survive in a specific environment
Sifune
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?

Ask