A program organization chart depicts the relationships between major program components. (A major component is a collection of entities packaged as a module.) The chart consists of a diagram that contains a box for each major component and arrows between boxes indicating supply lines.
Components are depicted by boxes with a special form. Each box is labeled with the name of the component (module) it depicts.
Supply lines are depicted by arrows from the component supplying an entity to the component making use of the entity. The arrow is labeled with the names of the entities being used in the component at the destination of the arrow.
Purpose of a Program Organization Chart
Pictorial Summary.
A program organization chart communicates in a pictorial
way how the major components of a program are put together
to form the program. The advantage of such a picture is that
it summarizes at a glance the overall structure of the
program.
Documentation.
The chart acts as documentation that people reviewing a
program can use to find their way around the code.
Such documentation is useful not only for completed
programs, but for programs being constructed.
It can help software engineers stay
aware of the big picture while they work on the parts.
Design.
The chart can also aid in the initial design process.
Software designers can sketch out major portions of
systems and revise and augment them as the ideas become
more clear.
Construction.
So, program organization charts serve useful functions
throughout the process of software design and construction.
They contain no information not
present in the program, once the program has been constructed.
At that point the chart
could be constructed automatically from the code.
A program to construct such a chart from the source files
for a program would be a useful piece
of software. Unfortunately, no such software exists on
the computer systems available to you, so you'll have to
draw them yourself.