Java Reference
In-Depth Information
9.8
(
The
Fan
class
) Design a class named
Fan
to represent a fan. The class contains:
■
Three constants named
SLOW
,
MEDIUM
, and
FAST
with the values
1
,
2
, and
3
to
denote the fan speed.
VideoNote
The
Fan
class
■
A private
int
data field named
speed
that specifies the speed of the fan (the
default is
SLOW
).
A private
boolean
data field named
on
that specifies whether the fan is on (the
default is
false
).
■
A private
double
data field named
radius
that specifies the radius of the fan
(the default is
5
).
■
A string data field named
color
that specifies the color of the fan (the default
is
blue
).
■
The accessor and mutator methods for all four data fields.
■
A no-arg constructor that creates a default fan.
■
A method named
toString()
that returns a string description for the fan. If
the fan is on, the method returns the fan speed, color, and radius in one com-
bined string. If the fan is not on, the method returns the fan color and radius
along with the string “fan is off” in one combined string.
Draw the UML diagram for the class and then implement the class. Write a test
program that creates two
Fan
objects. Assign maximum speed, radius
10
, color
yellow
, and turn it on to the first object. Assign medium speed, radius
5
, color
blue
, and turn it off to the second object. Display the objects by invoking their
toString
method.
■
**9.9
(
Geometry: n-sided regular polygon
) In an
n
-sided regular polygon, all sides
have the same length and all angles have the same degree (i.e., the polygon is
both equilateral and equiangular). Design a class named
RegularPolygon
that
contains:
A private
int
data field named
n
that defines the number of sides in the poly-
gon with default value
3
.
■
A private
double
data field named
side
that stores the length of the side with
default value
1
.
■
■
A private
double
data field named
x
that defines the
x
-coordinate of the poly-
gon's center with default value
0
.
■
A private
double
data field named
y
that defines the
y
-coordinate of the poly-
gon's center with default value
0
.
■
A no-arg constructor that creates a regular polygon with default values.
■
A constructor that creates a regular polygon with the specified number of sides
and length of side, centered at (
0
,
0
).
■
A constructor that creates a regular polygon with the specified number of sides,
length of side, and
x
- and
y
-coordinates.
■
The accessor and mutator methods for all data fields.
■
The method
getPerimeter()
that returns the perimeter of the polygon.
■
The method
getArea()
that returns the area of the polygon. The formula for
s
2
n
*
computing the area of a regular polygon is
Area
=
≤
.
n
4
*
tan
¢
Draw the UML diagram for the class and then implement the class. Write a test
program that creates three
RegularPolygon
objects, created using the no-arg
constructor, using
RegularPolygon(6, 4)
, and using
RegularPolygon(10,
4, 5.6, 7.8)
. For each object, display its perimeter and area.
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