HP HP-67 - Page 146

142 Simple Programming
You can see the similarities. At times, a flowchart may duplicate the
set of instructions exactly, as shown above. At other times, it may be
more useful to have an entire group of instructions represented by a
single block in the flowchart. For example, here is another flowchart
for the program to calculate the area of a circle:
Calculate 7r?
Here an entire group of instructions was replaced by one block in the
flowchart. This is a common practice, and one which makes a flow-
chart extremely useful in visualizing a complete program.
You can see how a flowchart is drawn linearly, from the top of the
page to the bottom. This represents the general flow of the program,
from beginning to end. Although flowcharting symbols sometimes
vary, throughout this handbook and in the Standard Pac, we have held
to the convention of circles for the beginning and end of a program or
routine, and rectangles to represent groups of functions that take an
input, process it, and yield a single output. We have used a diamond to
represent a decision, where a single input can yield either of two
outputs.