lab03


Goals:
* To use program design techniques to tackle more sophitiscated specifications
* To develop more sophisticated Java classes
* To create and use meaningful test suites
* To develop programs using mathematical expressions 
* To develop programs using conditional structures (if's)
* To (possibly) use online debugging tools
* Extra credit questions: To develop programs using loops


For each project, make sure 
that the project folder contains a test suite, 
that this test suite is used to thoroughly test the project, and
that the results from this testing are documented in the project code.
You may also want to copy the test suite into your Lab Log, in case there is
an open-notes quiz about this topic.


0. Complete all the Chapter 3 exercises. Challenge exercises are required.
  
   Some of the exercises, such as 3.13, are not about writing or executing a
   Java program. Instead, they ask a question.  As we discussed before, 
   the "answer" to these exercises should be typed or neatly handwritten 
   in your Lab Log Book (LLB).  This LLB can be a simple text document 
   prepared on your favorite word processor.  Make sure you print your updated 
   LLB after every lab and bring it to class, in case the professor gives a 
   open-notes quiz!

1. Implement the following enhancements to the Student class of Chapter 2:

   a. Add a method with the following signature

   // @return "frosh", "soph", "jr", or "sr",
   // depending on the range that credits falls into
   public String getStudClass ()

   b. Add three new private attributes to the class to store the grades 
   received by a Student object on three evaluations.  
   Now modify the existing constructor to give default values to these new
   attributes.

   Once this has been completed, add a(several) mutator(s) to class that
   allows a client to set the values of the evaluations for a Student object.

   c. Add a new constructor that will receive as
   parameters the initial values for all private attributes (to do this,
   copy-and-paste from the current constructor and add three more parameters
   for the initial values of the grades!).   

   d. Add three accessors that will give a client of the class access to 
   the highest grade value, the lowest grade value, and the middle grade value
   for a Student object.


2. Implement a ChangeMaker class that will be used to help cashiers give change.
   Given an amount of money (less than $1) the class should provide a feature
   to display the best way to give that amount of change. Develop a careful 
   test suite for your class. Test your class with your test suite and document
   the outcomes. Are you confident that your implementation and Java's 
   arithmetic do not result in precision or roundoff errors?


3. Create a FancyInt class project under h:\ioop\lab03\fancyInt.
   The class must provide the following functionality:
   a. A feature that allows a client to create a FancyInt object and give it 
   an initial value as a parameter.
   
   b. A feature that returns the value of _this_.
   The class should implement this feature via a public method with 
   the following signature:

   // @return value of _this_ 
   public int getValue ()

   Also implement the corresponding mutator, setValue.

   c. A feature that returns whether or not a FancyInt is positive.
   The class should implement this feature via a method with 
   the following skeleton:

   // @return true when _this_ is positive; otherwise, returns false
   public boolean isPositive ()
   {
      boolean result;

      result = true; // dummy result initialization; ??? FIX ME
  
      return true; 
   } // isPositive

   d. A feature that returns whether or not a FancyInt is even.

   e. A feature that views the value of _this_ as a temperature 
   in degrees Celsius and returns its Fahrenheit equivalent.
   The class should implement this feature via a method with 
   the following signature:

   // @return the Fahrenheit equivalent of _this_
   public double getFahrenheit ()

   f. A feature that views the value of _this_ as a temperature 
   in degrees Fahrenheit and returns its Celsius equivalent.

   g. A feature that views the value of _this_ as a year 
   and returns whether or not it is a leap year. 
   Remember that a leap year is a year with 366 days.  
   All leap years are multiples of 4, but not multiples of 100. 
   Years that are multiples of 400 are an exception to the previous rule.  
   For example,
      1996 is leap,
      1997 is not leap,
      1900 is not leap, and
      2000 is leap.
   There are no leap years before 1582 (when the Gregorian calendar
   and the concept of leap year were introduced).

   THE REMAINING SECTIONS OF THIS QUESTION
   are extra credit for this lab. You will not be able to solve them unless
   you know about loops. These sections will be required later.

   h. A feature that returns whether or not a FancyInt is prime.
   Remember that a positive integer is prime when its only divisors are
   1 and itself. By convention, the smallest prime number is 2.

   i. A feature that returns whether or not a FancyInt is perfect.
   Remember that a positive integer is perfect when the sum of its divisors
   is (2 * itself). For example, the first perfect number is 6 since
   (1+2+3+6) = 12 = 2*6. The next perfect number is 28.

   j. A feature that returns the binary equivalent of the value of _this_.
   The class should implement this feature via a method with 
   the following signature:

   // @return when _this_ is positive, a String with its binary equivalent;
   // otherwise, the empty String 
   public String getBinaryString ()

   k. A feature that returns a BinaryNumber initialized to the binary 
   equivalent of the value of _this_.
   The class should implement this feature via a method with 
   the following signature:

   // @return the equivalent BinaryNumber
   public BinaryNumber getBinaryNumber ()

   To accomplish this task, you will need to implement a BinaryNumber class. 

   l. A feature that returns the greatest common divisor of _this_ and
   another FancyInt.
   The class should implement this feature via a method with 
   the following signature:

   // @return the greatest common divisor of _this_ and f
   public int getGCD (FancyInt f)

   m. A feature that returns the set of all the divisors of _this_ .
   The class should implement this feature via a method with 
   the following signature:

   // @return the set of all divisors of _this_
   public ArrayList getDivisors ()


4. EXTRA CREDIT if completed by our next the lab. (This will "be on the test.")

   a. Develop a BinaryNumber class.  This class must implement the method
      
      public int decimalEquivalent ();

      Your class only needs to handle "positive" values, and you may benefit
      from studying the API for the String class.  

      Didactic note: The purpose of this lab is for you to practice creating
      and testing your own class, developing an algorithm, and using loops and
      ifs. In case you find, by any chance, a Java library function that 
      that converts decimal to binary, please DO NOT USE IT and solve the
      problem from scratch instead.