CS 4448 - Fall 1998
Object-Oriented Programming and Design
Lecture 4

Discuss Homework #2

Inheritance
- Does number know how to become a Triple, yes and no. Depends on your implementation.
- Don't need super with x and y method in Triple, why?
- Why did we need to implement storeOn: or did we?
- A Point is just a 2D Triple on the 0 plain.
- Reuse!!!! @, asTriple, Round, min: ...
Smalltalk
instance variables, class variables
io - aStream nextPut: $@ , printOn: aStream
Does no type checking mean no Templates?
Chapter 4

C++
member variables/attributes/data, static var/att/data
Templates P.82 - used mainly to parameterize(generic) classes
.hh versus .cc files
Privileges(private) used with constructor and destructor can help in memory management. You can not create object but other class can P.110
io - Streams(istreams, ostreams) - cin >> , cout << P.89 or printf
Macros - #define #ifndef #endif is used by the preprocessor
Discuss Homework #4
Molecule check if it is water
inheritance limited for some - duplicate code results in errors and trouble for maintainability and future reusability.
inheritance must be used correctly - wrong answers vs. no answer
hard coded answers can be bad, # of legs
Calling the parent constructor new or specialized with info
OO - encapsulation, modularity, abstraction, design hierarchy
Design is based on analysis which can change. One design does not fit all situations.
Design Hierarchy vs. real life hierarchy
Examination #1 next week