CS 4448 - Fall 1998
Object-Oriented Programming and Design
Homework #4

Due on Monday, September 28.

Bring 2 copies of your homework to class and don't turn them in until after I give you further instructions. If you can not make class talk to me before hand and we can work something out.

Do Design for Homework #3

Show your designs using Class Diagrams and Module Diagrams. Be open minded in your design. Consider future enhancements and see the big picture. Anticipate future needs that one might have on your design. It should be noted that no design is ever final, we always go back at some later date and make modifications. MS Word seemed complete but then we decide it needs to generate HTML. So if the designers did a good job it only takes a minor redesign to generate HTML. But then it is decided that MS Word needs to be not only a word processor but also a web browser. This time it is a larger redesign but again it is done with hopes of anticipating future design needs. Enough said, go to it.

Why fixed names?

The class names and method names are fixed since someone else wants your classes for use by their classes. This hypothetical, "They", have created their own stubs for some of the code and will be replacing them with your code.

This time the syntax I am using is SmallTalk

Classes and class methods that need to work for instantiation

Dog weight: name: kind:
Cat weight: name: kind:
Sprinter weight: name:
Molecule name: 'Water' (Comment - The string Water is just one example)
Beaker name: 'MagnesiumChloride' (Comment - Just an example name)
Magnesium new
Chlorine new
Hydrogen new
Krypton new
Pine weight: height:
Plant new
Animal new
BeakerHolder new
CouchPotato weight: name: (Comment - For those from different cultures, this is a person who watches TV all day and does not move unless they need a beer or to go to the bathroom)
Student weight: name:

Some additional classes that might help you design include: Mammal, Quadraped, Biped, Human, Tree, and last but not least a MaterialObject. Note: name may not be set after instantiation. Every object for our design, comes into existence with a name and never changes it. Periodic Table for your perusal.

Instances and minimum instance methods

aDog speak; name; topSpeed; hasLiveYoung; spontaneousMovement
aCat speak;legs
aSprinter topSpeed;
aStudent speak; legs
aBeaker numberOfAtoms; name
aMolecule mass; name; chemicalSymbol
aHydrogen mass; chemicalSymbol
aKrypton name; family
aPine deciduous;height
aPlant alive
aBeakerHolder find: ; hold: ; giveBack: (Comment: think of giveBack as unhold, add and remove might give you ideas of what hold: and giveback: do)
anAnimal hasSex (Comment: this method is not a social commentary but a question about gender :)
aBeaker add: ; remove: (Comment: these methods let you add and remove atoms to the beaker)
aCouchPotato speak; topSpeed; spontaneousMovement (Comment: See Animal vs. Plant in the dictionary. I agree see your question and I don't know the answer either. Is a CouchPotato Animal or Vegetable or Mineral, but certainly not the Model of a Modern Major General)