PPG Application Design
16
PT Program Generator (PPG) v5.0
Application Structure
Next you must decide what you want the program to do. Draft a program flow
chart with pencil and paper, while keeping in mind the following ideas and
concepts.
Follow them as steps if you like:
1. List the major actions the user may take. These may include reading
data from the scanner, uploading data from the PDT, and storing data
in a file.
2. For each major action, define each step. In what order will the actions
be taken? Walk through each step as if you were the end user.
3. Do multiple actions contain the same step? If so, save time and pro-
gram size by putting these steps into a subroutine that can be called
from different areas of the program.
4. Will each action be taken in a specific order or will the user be allowed
to choose an action? To offer a choice of actions, such as collecting
and uploading data, you can provide a menu that will allow the user
to select an action.
5. Visualize the individual steps involved in each major action.
•
For example, will the user be collecting different types of data at
different times?
•
For each action you would take as a portable user, imagine the
options you would expect to have and the messages you would
expect to appear on the screen.
6. In what order will the actions be taken?
•
Is there an obvious direction to the program? For example, a user
would normally collect data and then upload it.
•
This order should be reflected in the main menu and in the
program flow.
7. How will the user start? Do you want to identify the user first by ask-
ing for a password or ID number? What about a log-on message?
8. To make your design clearer, try breaking your design up into logical
sections. As a guideline, if a function contains more than ten steps,
you may want to break it down further. Keeping each frame small will
make your program easier to implement and maintain.
2342.book Page 16 Thursday, July 22, 2004 8:35 AM
