Object Oriented Programming using C#
Case Study
Synonyms
The following are synonyms :-
• Nouns:- LCD message display board = display board
- scrolling text message = message
- ID number = ID
- credit units = client’s credit = credit
- set of current messages = message set
- days = number of days = days remaining
• Verbs:- show = display
By identifying synonyms we avoid needless duplication and confusion in the system.
Potential Classes, Attributes and Methods
Nouns that describe significant entities for which we can identify properties i.e. data and behaviour i.e. methods could
become classes within the system. These include :-
• Client
• Message
• ClientBook
• MessageSet
• DisplayBoard
• DummyDisplayBoard
Nouns that are would be better as attributes of a class rather than becoming a class themselves :-
• For a ‘client’:
- ID
- name
- address
- phone number
- credit
• For a ‘message’: - text
- days remaining
- cost of message
Each of these could be modelled as a class (which Client or Message would have as an object attribute), but we decide
that each of them is a sufficiently simple piece of information that there is no reason to do so – each one can be a simple
attribute (instance variable) of a primitive type (e.g. int) or library class (e.g. String).