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If you wrote down the following for the program output, you already understand most of the material covered in this module and you can probably skipthis module and move on to the next module.

Collection data Joe Bill Tom JOE BILL TOMRaw array data Joe Bill Tom JOE BILL TOMNatural order sorted array data BILL Bill JOE Joe TOM TomCustom order sorted array data Tom TOM Joe JOE Bill BILLCollection data Joe Bill Tom JOE BILL TOM

If you didn't write down the correct output for the program in Listing 1 , you should probably continue with your study of this module.

Similar to previous programs

Although this program is somewhat more complex, the overall structure of this program is similar to programs that I have discussed in previous modules.Therefore, I will concentrate on those aspects of this program that differentiate it from the programs in previous modules.

A new Vector object

The code in Listing 2 instantiates a new object of the Vector class and stores a reference to that object in the variable named ref .

Listing 2 . A new Vector object.
ref = new Vector();

The Vector class was part of Java long before the Collections Framework was released. However, with the release of the Collections Framework,the Vector class was upgraded to implement the Collection interface and the List interface.

A Vector is a List

Therefore, a Vector is a List , and adheres to the various contracts of the List interface. For example, since it is not a Set , it doesn't prohibit duplicate elements. Because it is a List , it is an ordered collection. The position of each element in the collection is determined by a numeric index associated with the element and is independent ofthe value of the element.

The fillIt method

As has been the case in several of the programs in previous modules, the code in Listing 3 passes the Vector object's reference to a method named fillIt where the Vector is populated with the names of several people.

Listing 3 . Call the fillIt method.

The code for the fillIt method is shown in Listing 4 . As you can see, the names were added to the collection in no particular order relative to theirvalues. (The add method for the Vector class simply adds each new element to the end of the list.)

Listing 4 . 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

Iteration on a Vector

When an iterator is used to traverse the elements in a Vector collection, the elements are delivered by the iterator in ascending index order,beginning with the element stored at index 0.

The code in Listing 5 gets and uses an iterator to display the contents of the populated collection.

Listing 5 . Iteration on a Vector.
iter = ref.iterator(); System.out.println("Collection data");while(iter.hasNext()){ System.out.print(iter.next() + " ");}//end while loop

The output

The code in Listing 5 produces the following output:

Questions & Answers

Need help solving this problem (2/7)^-2
Simone Reply
what is the coefficient of -4×
Mehri Reply
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
Alfred Reply
An investment account was opened with an initial deposit of $9,600 and earns 7.4% interest, compounded continuously. How much will the account be worth after 15 years?
Kala Reply
lim x to infinity e^1-e^-1/log(1+x)
given eccentricity and a point find the equiation
Moses Reply
12, 17, 22.... 25th term
Alexandra Reply
12, 17, 22.... 25th term
College algebra is really hard?
Shirleen Reply
Absolutely, for me. My problems with math started in First grade...involving a nun Sister Anastasia, bad vision, talking & getting expelled from Catholic school. When it comes to math I just can't focus and all I can hear is our family silverware banging and clanging on the pink Formica table.
I'm 13 and I understand it great
I am 1 year old but I can do it! 1+1=2 proof very hard for me though.
Not really they are just easy concepts which can be understood if you have great basics. I am 14 I understood them easily.
find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
If f(x) = x-2 then, f(3) when 5f(x+1) 5((3-2)+1) 5(1+1) 5(2) 10
how do they get the third part x = (32)5/4
kinnecy Reply
make 5/4 into a mixed number, make that a decimal, and then multiply 32 by the decimal 5/4 turns out to be
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
is it a question of log
I rally confuse this number And equations too I need exactly help
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
greetings from Iran
salut. from Algeria
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
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
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
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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
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