CSE/IT 213: Homework 1

CSE/IT 213: Homework 1

Problem
For this homework, you need to write 3 classes: Test, Rectangle, and a Sphere class. Remember to use a package for your source code. Name the package following the rules outlined in
homework 0. For this homework, you will have one package which contains 3 classes.
UML
The classes are described using the UML modeling language. UML uses a simple schema to
model classes.
Following the name of the method or constructor, parameters are included in the (). The
method’s return type follows a colon. For example
Rectangle(width : double, height : double)
is a public constructor that takes two double parameters. You know its a constructor as it
has the same name as the class followed by parentheses.
area() : double
is a method that takes no parameters and returns a double.
The organization of the UML model is:
Class Name
----------------
Instance fields
----------------
Constructors
----------------
Methods
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CSE/IT 213 CSE/IT 213: Homework 1
Often is the case that the instance fields and constructors are left off the UML diagram as
well as setters and getters for the instance fields.
Some authors precede the names with a + or − to distinguish public (+) from private (−)
instance fields and methods. However, often that detail is omitted as it is here.
Test class
The Test class contains the main() method whose purpose is to test the other classes. Make
sure you test all constructors and methods of the Rectangle and Sphere class. Test with
what you think is appropriate data.
Rectangle class
Rectangle
---------------------
Rectangle()
Rectangle(width : double, height : double)
Rectangle(x : double, y : double, width : double, height : double)
---------------------
area() : double
perimeter() : double
diagonalLength() : double
distanceFromOrigin() : double
The Rectangle class has three constructors: 1) a default constructor that defaults to a unit
square of width one and a height of one with the lower left hand corner located at the origin
and the upper right hand corner at point (1,1); 2) a constructor that sets the width and
height of the rectangle, but keeps the default location of the lower left hand corner of the
rectangle; and 3) a constructor that can set the width, height and, position of the lower left
hand corner of the rectangle.
Methods of the Rectangle class are: find the area of the rectangle, its perimeter, the length
of the diagonal of the rectangle, and the distance the lower left hand corner of the rectangle
is from the origin.
Make sure you have setters and getters for all instance fields.
Sphere Class
The Sphere class is similar to the Rectangle class.
Sphere
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CSE/IT 213 CSE/IT 213: Homework 1
---------------------
Sphere()
Sphere(radius : double)
Sphere(x : double, y : double, z : double)
Sphere(x : double, y : double, z : double, radius : double)
---------------------
volume() : double
surfaceArea() : double
distanceFromOrigin() : double
The sphere class has four constructors: 1) the default constructor defaults to a sphere of
radius 1 centered at the origin (0, 0, 0); 2) a constructor that sets the radius, but keeps the
sphere centered at the origin; 3) a constructor that sets the center position of the sphere but
keeps the radius one; and 4) a constructor that sets the position and the radius.
Methods of the Sphere class are: find the volume of the sphere, find the surface area of the
sphere, and find the distance the center of the sphere is to the origin. Use Math.PI for the
value of PI.
Make sure you have getters and setters for all instance fields.
Comments
Make sure all classes and methods are commented. Follow these simple rules.
In general, the rule for comments is that comments explain why, not the how.
Every class begins with the class comment that was described in homework 0.
In general, test classes need a class comment and, if needed, one liners about the main
method’s logic.
Instance fields should have a comment after its declaration, stating what it is used for if its
purpose is not clear from its name.
int foo; //a brief description of foo
Every method, except main(), has the following comment structure:
/**
* A brief description of what fooBar does.
*
* @param foo a description of foo
* @param bar a description of bar
* @return a description what is returned.
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CSE/IT 213 CSE/IT 213: Homework 1
*
* Remarks: Any remarks, assumptions, etc goes here.
* The @return tag is not used if the method returns void
*/
public int fooBar(int bar, String bar) {
//statements
}
NB that all parameters are commented for methods using the @param tag.
Java Coding Style
Except for 4 space indentation, follow Google’s Java Style guide, which is available at
http://google-styleguide.googlecode.com/svn/trunk/javaguide.html
Submission
Create a jar file of your 3 classes named
cse213 firstname lastname hw1.jar
Upload the jar file to Canvas before the due date.
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