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this class to be initialized when it's declared. The constructor should store the fraction in reduced
form. The fraction
2/4
is equivalent to
1/2
and would be stored in the object as 1 in the
numerator
and 2 in the
denomina-
tor
. Provide a no-argument constructor with default values in case no initializers are provided. Pro-
vide
public
methods that perform each of the following operations:
a) Add two
Rational
numbers: The result of the addition should be stored in reduced
form. Implement this as a
static
method.
b) Subtract two
Rational
numbers: The result of the subtraction should be stored in re-
duced form. Implement this as a
static
method.
c) Multiply two
Rational
numbers: The result of the multiplication should be stored in
reduced form. Implement this as a
static
method.
d) Divide two
Rational
numbers: The result of the division should be stored in reduced
form. Implement this as a
static
method.
e) Return a
String
representation of a
Rational
number in the form
a/b
, where
a
is the
numerator
and
b
is the
denominator
.
f) Return a
String
representation of a
Rational
number in floating-point format. (Con-
sider providing formatting capabilities that enable the user of the class to specify the
number of digits of precision to the right of the decimal point.)
8.16
(Huge Integer Class)
Create a class
HugeInteger
which uses a 40-element array of digits to
store integers as large as 40 digits each. Provide methods
parse
,
toString
,
add
and
subtract
. Meth-
od
parse
should receive a
String
, extract each digit using method
charAt
and place the integer
equivalent of each digit into the integer array. For comparing
HugeInteger
objects, provide the fol-
lowing methods:
isEqualTo
,
isNotEqualTo
,
isGreaterThan
,
isLessThan
,
isGreaterThanOrEqualTo
and
isLessThanOrEqualTo
. Each of these is a predicate method that returns
true
if the relationship
holds between the two
HugeInteger
objects and returns
false
if the relationship does not hold. Pro-
vide a predicate method
isZero
. If you feel ambitious, also provide methods
multiply
,
divide
and
remainder
. [
Note:
Primitive
boolean
values can be output as the word “true” or the word “false” with
format specifier
%b
.]
8.17
(Tic-Tac-Toe)
Create a class
TicTacToe
that will enable you to write a program to play Tic-
Tac-Toe. The class contains a private 3-by-3 two-dimensional array. Use an
enum
type to represent
the value in each cell of the array. The
enum
's constants should be named
X
,
O
and
EMPTY
(for a po-
sition that does not contain an
X
or an
O
). The constructor should initialize the board elements to
EMPTY
. Allow two human players. Wherever the first player moves, place an
X
in the specified square,
and place an
O
wherever the second player moves. Each move must be to an empty square. After
each move, determine whether the game has been won and whether it's a draw. If you feel ambi-
tious, modify your program so that the computer makes the moves for one of the players. Also, allow
the player to specify whether he or she wants to go first or second. If you feel exceptionally ambi-
tious, develop a program that will play three-dimensional Tic-Tac-Toe on a 4-by-4-by-4 board
[
Note:
This is an extremely challenging project!].
8.18
(
Account
Class with
BigDecimal
balance
)
Rewrite the
Account
class of Section 3.5 to store
the
balance
as a
BigDecimal
object and to perform all calculations using
BigDecimal
s.
Making a Difference
8.19
(Project: Emergency Response Class)
The North American emergency response service,
9-1-1
,
connects callers to a
local
Public Service Answering Point (PSAP). Traditionally, the PSAP would ask
the caller for identification information—including the caller's address, phone number and the nature
of the emergency, then dispatch the appropriate emergency responders (such as the police, an ambu-
