Description
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):
• DecagonalPrism.java
• DecagonalPrismApp.java
Specifications
Overview: You will write a program this week that is composed of two classes: (1) DecagonalPrism
that defines object for 3-D geometric shape objects with ten square side faces and two regular
decagon caps) where edge and height are non-negative, and (2) DecagonalPrismApp, which has a
main method that reads in data, creates a DecagonalPrism object, and then prints the object. AB
A decagonal prism is a 3-D geometric shape formed by ten square side faces and two regular decagon
caps. The decagonal prism has 12 faces, 30 edges, and 20 vertices. A decagonal prism can be defined by
its base edge (a) and height (h) as depicted below. The formulas are provided to assist you in computing
return values for the respective methods in the DecagonalPrism class described in this project.
Nomenclature
Base edge: a
Height: h
Surface area: A
Base area: AB
Lateral surface area: AL
Volume: V
Formulas
• DecagonalPrism.java
Requirements: Create a DecagonalPrism class that stores the label, edge, and height (edge and
height each must be non-negative). The DecagonalPrism class also includes methods to set and
get each of these fields, as well as methods to calculate the surface area, base area, lateral surface
area, and volume of a DecagonalPrism object, and a method to provide a String value of a
DecagonalPrism object (i.e., an instance of the DecagonalPrism class).
Project: Decagonal Prism App Page 2 of 5
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Design: The DecagonalPrism 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. These instance variables should be private so that they are not directly accessible
from outside of the DecagonalPrism class, and these should be the only instance variables in
the class.
(2) Constructor: Your DecagonalPrism class must contain a constructor that accepts three
parameters (see types of above) representing the label, edge, and 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 DecagonalPrism 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.
DecagonalPrism ex1 = new DecagonalPrism(“Small Example”, 2.0, 5.0);
DecagonalPrism ex2 = new DecagonalPrism(” Medium Example “, 10.4, 32.6);
DecagonalPrism ex3 = new DecagonalPrism(“Large Example”, 50, 100);
(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 DecagonalPrism are described below. See the formulas above and “Code and
Test” below for details. When implementing the formulas, be sure to use the methods
Math.pow and Math.sqrt as appropriate.
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 trimmed String is set to the label field and the method returns true.
Otherwise, the method returns false and the label field is not set.
o getEdge: Accepts no parameters and returns a double representing the edge field.
o setEdge: Accepts a double parameter and returns a boolean. If the edge is nonnegative, sets edge field and returns true. Otherwise, the method returns false, and the
edge field is not set.
o getHeight: Accepts no parameters and returns a double representing the height field.
o setHeight: Accepts a double parameter and returns a boolean. If the height is nonnegative, sets height field and returns true. Otherwise, the method returns false and the
height field is not set.
o surfaceArea: Accepts no parameters and returns the double value for the surface
area calculated using the edge and height.
o baseArea: Accepts no parameters and returns the double value for the base area
calculated using the edge.
o lateralSurfaceArea: Accepts no parameters and returns the double value for the
slant height calculated using the edge and height.
Project: Decagonal Prism App Page 3 of 5
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o volume: Accepts no parameters and returns the double value for the volume calculated
using edge and height.
o toString: Returns a String containing the information about the DecagonalPrism
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(), baseArea(), lateralSurfaceArea(), and volume(). Each line should have no
leading and no trailing spaces (e.g., there should be no spaces before a newline (\n) other
than tab (\t) as appropriate). The toString value for ex1, ex2, and ex3 respectively are
shown below (the blank lines are not part of the toString values; that is, the return value
should not begin with a newline (\n) character and should not end with a newline (\n)
character).
A decagonal prism “ex1” with edge = 2.0 units and height = 5.0 units, has:
surface area = 161.554 units
base area = 30.777 square units
lateral surface area = 100.0 square units
volume = 153.884 cubic units
A decagonal prism “ex2” with edge = 10.4 units and height = 32.6 units, has:
surface area = 5,054.811 units
base area = 832.206 square units
lateral surface area = 3,390.4 square units
volume = 27,129.903 cubic units
A decagonal prism “ex3” with edge = 50.0 units and height = 100.0 units, has:
surface area = 88,471.044 units
base area = 19,235.522 square units
lateral surface area = 50,000.0 square units
volume = 1,923,552.211 cubic units
Code and Test: As you implement your DecagonalPrism 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 DecagonalPrism in interactions (see 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 DecagonalPrism 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 DecagonalPrism then prints it out. This would be
similar to the class you will create in DecagonalPrismApp, except that in DecagonalPrismApp
you will read in the values and then create the object.
• DecagonalPrismApp.java
Requirements: Create DecagonalPrismApp class with a main method that reads in values for
label, edge, and height. After the values have been read in, main creates a DecagonalPrism object
and then prints the object.
Project: Decagonal Prism App Page 4 of 5
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Design: The main method should prompt the user to enter the label, edge, and height. After a
value is read in for edge, if the value is less than zero, an appropriate message (see examples
below) should be printed followed by a return from main. Do the same after a value for height is
read in. Assuming that both edge and height are non-negative, a DecagonalPrism object should be
created and printed. Below are examples where the user has entered negative values for edge
and height followed by an example using the values from the first example above for label, 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, edge, and height for a decagonal prism.
label: ex1
edge: 2.0
height: 5.0
A decagonal prism “ex1” with edge = 2.0 units and height = 5.0 units, has:
surface area = 161.554 units
base area = 30.777 square units
lateral surface area = 100.0 square units
volume = 153.884 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. If you need to convert the String to a double,
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, edge, and height, use a tab “\t” rather than three
spaces.
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 DecagonalPrism, you should ensure
that all 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 a
Line # Program input/output
1
2
3
4
5
Enter label, edge, and height for a decagonal prism.
label: Bad edge value
edge: -2
Error: edge must be non-negative.
Line # Program input/output
1
2
3
4
5
6
Enter label, edge, and height for a decagonal prism.
label: Bad height value
edge: 0
height: -5.8
Error: height must be non-negative.
Project: Decagonal Prism App Page 5 of 5
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DecagonalPrism object. Web-CAT will test all of the methods specified above for the
DecagonalPrism class to determine your project grade.
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 DecagonalPrism 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 setHeight(3.5) is invoked, it returns true to let the caller
know the radius field was set; whereas setHeight(-3.5) will return false since the radius field
is not set. If the caller knows that x is positive, then the return value of setHeight(x) can
safely be ignored since it can be assumed to be true.
3. Even though your main method may not be using the return type of a method, you can ensure
that the return type is correct using interactions.
