2) Brief overview of  Lab 9
CS100M Spring 2004
Introduction to OOP

0) Create a file called e9sol.txt and give it an
   appropriate header. Answer the following questions
   in this file. There is quite a bit to do--you might need
   to work on this after lab.

1) What does OOP stand for?

2) Why are doing OOP?

3) What is the difference between a primitive and
   object type?

4) Obtain the code for NonOOP from lecture.
   Rewrite the methods to include two more people.
   Copy the revised code for maxGPA in e9sol.

5) Obtain the code for OOP1 from lecture.
   Add a method called avgGPA in class Student that
   returns the average GPA of all students in array s.
   Copy avgGPA in e9sol.

6) Obtain the code for TestComplex from lecture.
   The mthod toString is showing up in Thursday's lecture.
   It's a built-in method that allows you to "stringify"
   an object. Whenever someone promotes an object value to
   a String, Java will invoke that object's toString method,
   which will do whatever the programmer has it do.

   a) Comment out the toString method and recompile/run
      the program. Read Panels 17 and 30 from the lecture 
      notes. Report what Java does for the modified program.

   b) Fix toString such it handles the case of when the
      imaginary component is negative.
 
   c) Add a subtraction method (sub) to class Complex.

   d) Add a multiplication method (mul) to class Complex.

   e) Write statements in method main that test your 
      sub and mul methods.

   f) Copy the entire program in e9sol.

7) Write a OO program that compares two Person's weights and
   reports which Person is heavier. So, you will have
   a Main Class that obtains information about the 
   Person from the user, creates two Persons (who have names
   and weights), and then reports who is heavier. The Person
   class will have 

     - fields for name and weight
     - methods for stringifying and doing a simple weight 
       comparison for the "current" person and another
       person.
     - a constructor for making a Person object

   Hint: The solution is strikingly similar to the 
   TestComplex program. Copy the entire code into e9sol.
   If you want to be extremely fancy, try to figure out
   how to use the code in Panel 9 from the lecture notes.

8) Bonus problem [10 points]: Rewrite the weight comparison
   program in (7) to read in several people. Store all of 
   the Person objects in an array. (See Panel 7.)
  
   Then (here's the trickiest part), use the select sort 
   algorithm to sort the array in ascending order. Print 
   out each Person in this sorted order. (You'll have to 
   look up the select sort algorithm. Put your entire
   bonus program in E9Bonus.java.