AbstrtactShape.java
AbstrtactShape.java
/*<listing chapter="1" number="6">*/
/**
* Listing 1.6
*
@author
Koffman and Wolfgang
*/
package
KW
.
CH01
.
Shapes
;
/** Abstract class for a geometric shape. */
public
abstract
class
AbstrtactShape
implements
Shape
{
/** The name of the shape */
private
final
String
shapeName
;
/**
* Initializes the shapeName.
*
@param
shapeName the kind of shape
*/
public
AbstrtactShape
(
String
shapeName
)
{
this
.
shapeName
=
shapeName
;
}
/**
* Get the kind of shape.
*
@return
the shapeName
*/
public
String
getShapeName
()
{
return
shapeName
;
}
@
Override
public
String
toString
()
{
return
"Shape is a "
+
shapeName
;
}
}
/*</listing>*/
ComputeAreaAndPerim.java
ComputeAreaAndPerim.java
/*<listing chapter="1" number="8">*/
/**
* Listing 1.8
*
@author
Koffman and Wolfgang
*/
package
KW
.
CH01
.
Shapes
;
import
java
.
util
.
Scanner
;
/**
* Computes the area and perimeter of selected figures.
*/
public
class
ComputeAreaAndPerim
{
/**
* The main program performs the following steps.
* 1. It asks the user for the type of figure.
* 2. It asks the user for the characteristics of that figure.
* 3. It computes the perimeter.
* 4. It computes the area.
* 5. It displays the result.
*
@param
args The command line arguments -- not used
*/
public
static
void
main
(
String
args
[])
{
AbstrtactShape
myShape
;
double
perimeter
;
double
area
;
myShape
=
getShape
();
// Ask for figure type
myShape
.
readShapeData
();
// Read the shape data
perimeter
=
myShape
.
computePerimeter
();
// Compute perimeter
area
=
myShape
.
computeArea
();
// Compute the area
displayResult
(
area
,
perimeter
);
// Display the result
System
.
exit
(
0
);
// Exit the program
}
/**
* Ask the user for the type of figure.
*
@return
An instance of the selected shape
*/
public
static
AbstrtactShape
getShape
()
{
Scanner
in
=
new
Scanner
(
System
.
in
);
System
.
out
.
println
(
"Enter C for circle"
);
System
.
out
.
println
(
"Enter R for Rectangle"
);
System
.
out
.
println
(
"Enter T for Right Triangle"
);
String
figType
=
in
.
next
();
switch
(
figType
)
{
case
"C"
:
case
"c"
:
return
new
Circle
();
case
"R"
:
case
"r"
:
return
new
Rectangle
();
case
"T"
:
case
"t"
:
return
new
RtTriangle
();
default
:
return
null
;
}
}
/**
* Display the result of the computation.
*
@param
area The area of the figure
*
@param
perim The perimeter of the figures
*/
private
static
void
displayResult
(
double
area
,
double
perim
)
{
System
.
out
.
printf
(
"The area is %.2f%nThe perimeter is %.2f%n"
,
area
,
perim
);
}
}
/*</listing>*/
lab001.png
lab01.png
lab1.png
Rectangle.java
Rectangle.java
/*<listing chapter="1" number="7">*/
/**
* Listing 1.7
*
@author
Koffman and Wolfgang
*/
package
KW
.
CH01
.
Shapes
;
import
java
.
util
.
Scanner
;
/**
* Represents a rectangle.
* Extends AbstrtactShape.
*/
public
class
Rectangle
extends
AbstrtactShape
{
// Data Fields
/** The width of the rectangle. */
private
double
width
=
0
;
/** The height of the rectangle. */
private
double
height
=
0
;
// Constructors
/** Constructs a default Rectangle */
public
Rectangle
()
{
super
(
"Rectangle"
);
}
/**
* Constructs a rectangle of the specified size.
*
@param
width the width
*
@param
height the height
*/
public
Rectangle
(
double
width
,
double
height
)
{
super
(
"Rectangle"
);
this
.
width
=
width
;
this
.
height
=
height
;
}
// Methods
/**
* Get the width.
*
@return
The width
*/
public
double
getWidth
()
{
return
width
;
}
/**
* Get the height.
*
@return
The height
*/
public
double
getHeight
()
{
return
height
;
}
/**
* Set the width
*
@param
width The new width
*/
public
void
setWidth
(
double
width
)
{
this
.
width
=
width
;
}
/**
* Set the height
*
@param
height The new height
*/
public
void
setHeight
(
double
height
)
{
this
.
height
=
height
;
}
/**
* Compute the area.
*
@return
The area of the rectangle
*/
@
Override
public
double
computeArea
()
{
return
height
*
width
;
}
/**
* Compute the perimeter.
*
@return
The perimeter of the rectangle
*/
@
Override
public
double
computePerimeter
()
{
return
2
*
(
height
+
width
);
}
/**
* Read the attributes of the rectangle.
*/
@
Override
public
void
readShapeData
()
{
Scanner
in
=
new
Scanner
(
System
.
in
);
System
.
out
.
println
(
"Enter the width of the Rectangle"
);
width
=
in
.
nextDouble
();
System
.
out
.
println
(
"Enter the height of the Rectangle"
);
height
=
in
.
nextDouble
();
}
/**
* Create a string representation of the rectangle.
*
@return
A string representation of the rectangle
*/
@
Override
public
String
toString
()
{
return
super
.
toString
()
+
": width is "
+
width
+
", height is "
+
height
;
}
}
/*</listing>*/
Shape.java
Shape.java
package
KW
.
CH01
.
Shapes
;
/**
* An interface for a geometric shape
*
@author
Koffman and Wolfgang
*/
public
interface
Shape
{
// abstract methods
/**
* Compute the area of the shape
*
@return
The area of the shape
*/
double
computeArea
();
/**
* Compute the perimeter of the shape
*
@return
The perimeter of the shape
*/
double
computePerimeter
();
/**
* Prompt the user for the parameters of the shape
* and read them.
*/
void
readShapeData
();
/**
* Get the width of the shape
*
@return
The width of the shape
*/
double
getWidth
();
/**
* Get the height of the shape
*
@return
The height of the shape
*/
double
getHeight
();
}
Ghost90
lab1.rar
