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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.
Populator.fillIt(ref);

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

Ayele, K., 2003. Introductory Economics, 3rd ed., Addis Ababa.
Widad Reply
can you send the book attached ?
Ariel
?
Ariel
What is economics
Widad Reply
the study of how humans make choices under conditions of scarcity
AI-Robot
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn Reply
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn
what is ecnomics
Jan Reply
this is the study of how the society manages it's scarce resources
Belonwu
what is macroeconomic
John Reply
macroeconomic is the branch of economics which studies actions, scale, activities and behaviour of the aggregate economy as a whole.
husaini
etc
husaini
difference between firm and industry
husaini Reply
what's the difference between a firm and an industry
Abdul
firm is the unit which transform inputs to output where as industry contain combination of firms with similar production 😅😅
Abdulraufu
Suppose the demand function that a firm faces shifted from Qd  120 3P to Qd  90  3P and the supply function has shifted from QS  20  2P to QS 10  2P . a) Find the effect of this change on price and quantity. b) Which of the changes in demand and supply is higher?
Toofiq Reply
explain standard reason why economic is a science
innocent Reply
factors influencing supply
Petrus Reply
what is economic.
Milan Reply
scares means__________________ends resources. unlimited
Jan
economics is a science that studies human behaviour as a relationship b/w ends and scares means which have alternative uses
Jan
calculate the profit maximizing for demand and supply
Zarshad Reply
Why qualify 28 supplies
Milan
what are explicit costs
Nomsa Reply
out-of-pocket costs for a firm, for example, payments for wages and salaries, rent, or materials
AI-Robot
concepts of supply in microeconomics
David Reply
economic overview notes
Amahle Reply
identify a demand and a supply curve
Salome Reply
i don't know
Parul
there's a difference
Aryan
Demand curve shows that how supply and others conditions affect on demand of a particular thing and what percent demand increase whith increase of supply of goods
Israr
Hi Sir please how do u calculate Cross elastic demand and income elastic demand?
Abari
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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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