This
video
[9:36 minutes]
extends the accumulator pattern from the summing pattern that
you have seen previously
to include the counting and in-graphics accumulator
patterns.
The video uses a graphics system call Zellegraphics that preceded
RoseGraphics, so you will see zg instead of rg
and other such small changes from what we use now.
First Do a Concrete Example By Hand
This video
[10:36 minutes]
works through an example of a technique that you will use often.
Note: The video uses the following example: Given a line, draw a
diamond from the line.
The video should have said that the given line is the
upper-left
line of the diamond. (Instead, the video wrongly spoke of "positive
slope".)
Follow the above link to read the above
page, but you do not have to follow its links to other
pages.
Optional additional reading:
Test-First Programming (aka Test-Driven Programming, TDD)
is widely used in Agile Software Development Processes,
as described at length in this optional
article on
Test-First
Programming
from the web site for the Agile management tool called
VersionOne.
You might find it helpful to review
previous videos, especially the ones on: