Java Reference
In-Depth Information
An
Iterator
is an interface for retrieving objects from a collection sequentially. An
Iterator
object allows you to access all the objects it contains serially - but only once.
There's no way to go back to the beginning.
❑
The
ListIterator
interface provides methods for traversing the objects in a collection
backwards or forwards.
❑
Objects stored in any type of
collection
can be accessed using
Iterator
objects.
❑
Objects stored in a
Vector
, a
Stack
, or a
LinkedList
can be accessed using
ListIterator
objects.
❑
Exercises
1.
Implement a version of the program to calculate prime numbers that we saw in Chapter 4 to use a
Vector
object instead of an array to store the primes. (Hint - remember the
Integer
class.)
2.
Write a program to store a deck of 52 cards in a linked list in random sequence using a
Random
class object. You can represent a card as a two character string -
"1C"
for the ace of
clubs,
"JD"
for the jack of diamonds, and so on. Output the cards from the stack as four
hands of 13 cards.
3.
Extend the program from the chapter that used a map to store names and telephone numbers
such that you can enter a number to retrieve the name.
4.
Implement a phone book so that just a surname can be used to search and have all the entries
corresponding to the name display.
