Description
Goals: Learn to design simple classes and classes with containment in Java. Learn to use the tester library to visualize the data and to run the tests.
1 Instructions
The names of the classes must be exactly the same as specified. The same is the case for the names and types of the fields within the class, as well as the order in which they are defined and listed as the constructor arguments. This allows us to design our own Examples class that tests your program.
Make sure you follow the style guidelines that WebCAT enforces. For now the most important ones are: using spaces instead of tabs, indenting by 4 characters, following the naming conventions (data type names start with a capital letter, names of fields and methods start with a lower case letter), and having spaces before curly braces.
You will submit this assignment by the deadline using the Web-CAT submission system. You may submit as many times as you wish. Be aware of the fact that close to the deadline the WebCAT system may slow down to handle many submissions – so try to finish early.
With each homework you will also submit your log file named pair-user1-user2.txt where you replace user1 and user2 with the usernames of the two partners.
On top of both files you will have five lines of comments as follows:
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// assignment 1 |
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// partner1-last-name partner1-first-name |
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// partner1-username |
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// partner2-last-name partner2-firt-name |
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// partner2-username |
(In the text file you do not need the two slashes)
Your submission sould consist of the following files:
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pair-user1-user2.txt – your log file
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Person.java – the data definitions and examples for Problem 1
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Pizza.java – the data definitions and examples for Problem 2
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ExamplesAlgorithms.java – the file with method definition and tests Problem 3
all combined into one HW1.zip file.
Due Date: Friday, September 13th, 5:59 pm.
Practice Problems
Work out these problems on your own. Save them in an electronic portfolio, so you can show them to your instructor, review them before the exam, use them as a reference when working on the homework assignments.
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Problem 2.4 on page 17
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Problem 3.1 on page 25
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Problem 4.4 on page 34
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Problem 5.3 on page 43
Problem 1
We are designing the data collection for the US Census Bureau. For each person we need to collect the following information:
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name to be represented as a String
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yob the year of birth given as a four digit number
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state of residence – given as the standard two letter abbreviation
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citizen a boolean value, true, if the person is a US citizen
Design the class Person that represents the information about each person for the census.
Make at least three examples of instances of this class.
Problem 2
Here is a data definition in DrRacket:
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;; A IPizza is one of |
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;; — Plain |
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;; — Fancy |
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;; A Plain is |
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;; — (make-plain String String) |
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(define-struct (plain crust cheese)) |
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;; A Fancy is |
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;; — (make-fancy IPizza String) |
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(define-struct (fancy base topping)) |
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Draw the class diagram that represents this data definition. If you generates this as so-called ASCI-art, you can include it in your submissin. If you just draw it on a paper, you do not need to submit it. We just think it will help you in visualzing how the data is organized.
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Convert this data definition into Java. Make sure you use the same names for data types and for the fields, as are used in the DrRacket data definitions. Also, make sure that the constructor arguments are given in the same order as shown.
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Include in your examples the following two piza orders:
– a pizza with “thin crust”, “mozarella” cheese, and two toppings: “mushrooms” and “olives”
– a “deep dish” pizza with “mixed” cheese, with topping of “pepperoni”, and “onions”
Make sure the two sample orders given above are named order1 and order2.
Name your file Pizza.java and the file and the class that holds the examples of pizza data ExamplesPizza
Problem 3
Designing methods.
Create a project with the file ExamplesAlgorithms.java given in the Lecture 1.
Note: Please, download the updated version (Sept 6 2013).
Run the program.
Design two additional static methods following the examples already shown:
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Method that computes the area of a circle, given its radius. The number π is written as Math.PI. The method header should be
static double circleArea(int rad)
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Method that computes the perimeter of a circle, given its radius. The method header should be
static double circlePerimeter(int rad)
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Add two test cases that checks whether two times area is nearly the same as radius times the perimeter.
Note: To test this method you need to use t.checkInexact(actual, expected, tolerance) where the tolerance is relative between the actual and expected values.
