Epson MX-70 User Manual page 28

Chapter 2
There is a lot happening, so we'd better disect the program (like a frog) to learn
all about it. Type
L I S T
to LIST the program on paper.
Push the FEED button to roll the printout past the lid. Tear it off and keep it
handy so we can study the program as we go along.
SAVE the program on tape (or disk) to avoid having to type it in later.
Line by Line
We're going to type the last program back in, a line at a time, analyzing it as we
go.
An alternate strategy is to load the entire program back in from disk or tape,
then delete all the lines except the ones being studied. A second alternative is to
leave the program in, inserting a REM before each line, removing the REMs as
we progress. A third alternative is to leave the program intact and temporarily
insert an END at Line 15, shifting it down the program as we progress.
Take your pick!
Line 10 is straightforward. It PRINTed, the "greetings," starting 14 spaces
from the left. Type it in and RUN, watching the head action as it prints.
G R E E T I N G S F R O M T H E G R A P H I C
Well, that was rather "pedestrian."
Line 20 has 3 PRINT statements on the same line. They are separated by
semicolons, which are usually optional. The first PRINT statement TAB
the print head over 22 spaces, the second sends one of those special CHR$
(character string) codes we mentioned earlier, and the third prints
"MX-70."
CHR$ (14) stands for:
Appendix B contains all the special codes, often called CONTROL
CODES.
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(TRS-80 etc. use LLIST)
Figure 2-3
print DOUBLE WIDTH.
S