Project: PentagonalPyramid App

Project: PentagonalPyramid App
Deliverables
Your project files should be submitted to Web-CAT by the due date and time specified. You may
submit your files to the skeleton code assignment until the project due date but should try to do this
much earlier. The skeleton code assignment is ungraded, but it checks that your classes and methods
are named correctly and that methods and parameters are correctly typed. The files you submit to
skeleton code assignment may be incomplete in the sense that method bodies have at least a return
statement if applicable or they may be essentially completed files. In order to avoid a late penalty for
the project, you must submit your completed code files to Web-CAT no later than 11:59 PM on the
due date for the completed code. If you are unable to submit via Web-CAT, you should e-mail your
files in a zip file to your TA before the deadline.
Files to submit to Web-CAT (both files must be submitted together):
• PentagonalPyramid.java
• PentagonalPyramidApp.java
Specifications
Overview: You will write a program this week that is composed of two classes: (1) one named
PentagonalPyramid that defines PentagonalPyramid objects, and (2) the other,
PentagonalPyramidApp, which has a main method that reads in data, creates a PentagonalPyramid
object, and then prints the object.
A PentagonalPyramid has a pentagon base and five isosceles triangle faces, six vertices, and 10 edges as
depicted below with base edge length a and height h. The formulas are provided to assist you in computing
return values for the respective methods in the PentagonalPyramid class described in this project.
Ref: Do a “Google” search on “pentagonal pyramid surface area” for details and an interactive solver.
Surface Area
(A)
Volume (V)
Edge length
(a)
Height (h)
• PentagonalPyramid.java
Requirements: Create a PentagonalPyramid class that stores the label, base edge (i.e., length of
an edge in the pentagonal base), and height. The base edge and height must be greater than zero.
The PentagonalPyramid class also includes methods to set and get each of these fields, as well as
methods to calculate the surface area and volume of a PentagonalPyramid object, and a method to
provide a String value of a PentagonalPyramid object (i.e., a class instance).
Project: PentagonalPyramid App Page 2 of 5
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Design: The PentagonalPyramid class has fields, a constructor, and methods as outlined below.
(1) Fields (instance variables): label of type String, base edge of type double, and height of type
double. Initialize the String to "" and the double to 0 in their respective declarations. These
instance variables should be private so that they are not directly accessible from outside of the
PentagonalPyramid class, and these should be the only instance variables in the class.
(2) Constructor: Your PentagonalPyramid class must contain a public constructor that accepts
three parameters (see types of above) representing the label, base edge, height. Instead of
assigning the parameters directly to the fields, the respective set method for each field
(described below) should be called. For example, instead of the statement label =
labelIn; use the statement setLabel(labelIn); Below are examples of how the
constructor could be used to create PentagonalPyramid objects. Note that although String
and numeric literals are used for the actual parameters (or arguments) in these examples,
variables of the required type could have been used instead of the literals.
PentagonalPyramid ex1 = new PentagonalPyramid("Ex 1", 1, 2);
PentagonalPyramid ex2 = new PentagonalPyramid(" Ex 2 ", 12.3, 25.5);
PentagonalPyramid ex3 = new PentagonalPyramid("Ex 3", 123.4, 900);
(3) Methods: Usually a class provides methods to access and modify each of its instance
variables (known as get and set methods) along with any other required methods. The
methods for PentagonalPyramid, which should each be public, are described below. See
formulas in Code and Test below.
o getLabel: Accepts no parameters and returns a String representing the label field.
o setLabel: Takes a String parameter and returns a boolean. If the string parameter is
not null, then the label field is set to the “trimmed” String and the method returns true.
Otherwise, the method returns false and the label field is not set.
o getBaseEdge: Accepts no parameters and returns a double representing the base edge
field.
o setBaseEdge: Accepts a double parameter and returns a boolean as follows. If the
double is greater than zero, sets the base edge field to the double passed in and returns
true. Otherwise, the method returns false and does not set the base edge field.
o getHeight: Accepts no parameters and returns a double representing the height field.
o setHeight: Accepts a double parameter and returns a boolean as follows. If the
double is greater than zero, sets the height field to the double passed in and returns true.
Otherwise, the method returns false and does not set the height field.
o surfaceArea: Accepts no parameters and returns the double value for the total
surface area calculated using formula above and the values of the base edge and height
fields. See code and test below regarding the Math.tan(x) method.
o volume: Accepts no parameters and returns the double value for the volume calculated
using formula above and the values of the base edge and height fields.
Project: PentagonalPyramid App Page 3 of 5
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o toString: Returns a String containing the information about the PentagonalPyramid
object formatted as shown below, including decimal formatting ("#,##0.0######")
for the double values. Newline and tab escape sequences should be used to achieve the
proper layout. In addition to the field values (or corresponding “get” methods), the
following methods should be used to compute appropriate values in the toString
method: surfaceArea() and volume(). Each line should have no trailing spaces
(e.g., there should be no spaces before a newline (\n) character). The toString value
for ex1, ex2, and ex3 respectively are shown below (the blank lines are not part of the
toString values).
PentagonalPyramid "Ex 1" with base edge = 1.0 and height = 2.0 units has:
 surface area = 7.008203 square units
 volume = 1.1469849 cubic units
PentagonalPyramid "Ex 2" with base edge = 12.3 and height = 25.5 units has:
surface area = 1,086.4892066 square units
volume = 2,212.4737204 cubic units
PentagonalPyramid "Ex 3" with base edge = 123.4 and height = 900.0 units has:
surface area = 305,081.9691528 square units
volume = 7,859,601.8538338 cubic units
Code and Test: Math.tan(x) expects x to be in radians rather than degrees. In the formula, 54
degrees can be converted to radians using Math.toRadians(54). The following combines the two
methods: Math.tan(Math.toRadians(54))
As you implement your PentagonalPyramid class, you should compile it and then test it using
interactions. For example, as soon you have implemented and successfully compiled the
constructor, you should create instances of PentagonalPyramid in interactions (e.g., copy/paste
the examples above). Remember that when you have an instance on the workbench, you can
unfold it to see its values. You can also open a viewer canvas window and drag the instance from
the Workbench tab to the canvas window. After you have implemented and compiled one or
more methods, create a PentagonalPyramid object in interactions and invoke each of your
methods on the object to make sure the methods are working as intended. You may find it useful
to create a separate class with a main method that creates an instance of PentagonalPyramid then
prints it out. This would be similar to the PentagonalPyramidApp class you will create below,
except that in the PentagonalPyramidApp class you will read in the values and then create and
print the object.
• PentagonalPyramidApp.java
Requirements: Create a PentagonalPyramidApp class with a main method that reads in values
for label, base edge, and height. After the values have been read in, main creates a
PentagonalPyramid object and then prints a new line and the object.
Design: The main method should prompt the user to enter the label, base edge, and height. After
a value is read in for base edge, if the value is less than or equal to zero, an appropriate message
(see examples below) should be printed followed by a return from main. Similarly, after a value
is read in for height, if the value is less than or equal to zero, an appropriate message (see
examples below) should be printed followed by a return from main. Assuming that base edge and
height are positive, a PentagonalPyramid object should be created and printed.
Project: PentagonalPyramid App Page 4 of 5
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Below is an example where the user has entered a non-positive value for base edge. Your
program input/output should be exactly as follows.
Line # Program input/output
1
2
3
4
Enter label, base edge, and height for a pentagonal pyramid.
 label: PentagonalPyramid with a bad base edge value
 base edge: -5
Error: base edge must be greater than 0.
Below is an example where the user has entered a non-positive value for height. Your program
input/output should be exactly as follows.
Line # Program input/output
1
2
3
4
5
Enter label, base edge, and height for a pentagonal pyramid.
 label: PentagonalPyramid with a bad height value
 base edge: 10.0
 height: 0
Error: height must be greater than 0.
Below is an example where the user has the values from ex1, the first example, above for label,
base edge, and height. Your program input/output should be exactly as follows.
Line # Program input/output
1
2
3
4
5
6
7
8
9
Enter label, base edge, and height for a pentagonal pyramid.
 label: Ex 1
 base edge: 1
 height: 2
PentagonalPyramid "Ex 1" with base edge = 1.0 and height = 2.0 units has:
 surface area = 7.008203 square units
 volume = 1.1469849 cubic units
Code: Your program should use the nextLine method of the Scanner class to read user input.
Note that this method returns the input as a String. Whenever necessary, you can use the
Double.parseDouble method to convert the input String to a double. For example:
Double.parseDouble(s1) will return the double value represented by String s1. For the
printed lines requesting input for label, base edge, and height, use a tab "\t" rather than three
spaces. After you have created the object, it can be printed simply by using its variable name;
i.e., when the object variable name is evaluated in the println statement, its toString() method
is automatically called. Thus, printing the object reference variable myObj is equivalent to
printing the return value of the myObj.toString() method call.
Test: You should test several sets of data to make sure that your program is working correctly.
Although your main method may not use all the methods in PentagonalPyramid, you should
ensure that all of your methods work according to the specification. You can use interactions in
jGRASP or you can write another class and main method to exercise the methods. The viewer
canvas should also be helpful, especially using the “Basic” viewer and the “toString” viewer for
an PentagonalPyramid object. Web-CAT will test all of the methods specified above for
PentagonalPyramid to determine your project grade.
Project: PentagonalPyramid App Page 5 of 5
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General Notes
1. All input from the keyboard and all output to the screen should done in the main method. Only one
Scanner object on System.in should be created and this should be done in the main method. All
printing (i.e., using the System.out.print and System.out.println methods) should be in the main
method. Hence, none of your methods in the PentagonalPyramid class should do any input/output
(I/O).
2. When a method has a return value, you can ignore the return value if it is no interest in the current
context. For example, when setBaseEdge(3.5) is invoked, it returns true to let the caller know the
base edge field was set; whereas setBaseEdge(-3.5) will return false indicating the edge field was not
set. If the caller knows that x is positive, then the return value of setBaseEdge(x) can safely be
ignored since it can be assumed to be true.
3. Even though your main method (or other methods) may not be using the return value of a method
such as setBaseEdge(x), you can ensure that the return type is correct by using interactions.