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Syndicate ZMagazine Issue 092
______________________________________
|Volume3|SYNDICATE ZMAGAZINE ISSUE #92
|Issue 6|_____________________________
|(c)1988|February 8, 1988
|_______|_____________________________
|EDITOR:|Ron Kovacs
|_______|_____________________________
|Asst Pb|Ken Kirchner
|_______|_____________________________
|Hdq BBS|XBN BBS 1-617-770-0026
|_______|_____________________________
|INDEX92|
|_______|_____________________________
| -=1=- |Oasis Under New Management
| -=2=- |Atari News Update from GEnie
| -=3=- |Guest Commentary--Dave Brehm
| -=4=- |Plents Page--NX1000 Review
| -=5=- |Review of SP408/808-NiteLite
| -=6=- |Best Of 1987 Survey Results
| -=7=- |From The Editors Desk
| -=8=- |**This Article Removed**
| -=9=- |Basic Programming--Part 6
|_______|_____________________________
| -=1=- |ZMag Newswire -=SPECIAL=-
|_______|_____________________________
...OASIS BBS Finds New Owner...
Reported by Zin Marie
Just before Christmas, 1987, a deal
was struck that transferred ownership
of OASIS BBS software from Leo Newman
to Z INNOVATORS Co. A few days later,
on Christmas day, OASIS III was
released to OASIS SysOps, and in
January, 1988, this new version of the
software was made available for
purchase by the general public.
OASIS 3 represents the last revision
of the BBS done my Mr. Newman and his
partner, Mr. Ralph Walden. In 1987,
Leo and Ralph put together four
updates to OASIS, in March, April,
May, and July. The 5/27/87 update to
OASIS, enabled the BBS to run separate
machine language modules. Toward the
latter half of 1987, OASIS became a
more popular BBS software for the
Atari 8-bits. The final update of
1987, was a revision that brought us
OASIS 3. Some of the features of OASIS
3 are:
- ARCVIEW function in the download
directories and in the message
bases.
- Change message subject when replying
to messages. Ends the long chains
of messages under one non-related
subject headings.
- Enabled modules to call other
modules automatically.
- Ratio restrictions on downloads.
The OASIS SysOp can set the user
level exempt from ratios.
When OASIS was enabled to run machine
language modules, a bright future
opened up for OASIS BBS software.
Under its new ownership, OASIS will
continue to be updated and revised. Z-
INNOVATORS Co. will employ the
programming skills of Miss Glenda
Stocks for this purpose. Miss Stocks
has been writing OASIS modules since
May, 1987. The first was the SURVEY
program, which conducts user surveys
from specially formatted text files,
created by anyone, even users
themselves. Other modules written by
Glenda include:
- EZMENU. Allows SysOps to create
sub-menus with a text editor. The
submenus allow downloading, reading
text files, displaying Atari
animation, and executing other
modules. EZMENUS can be linked
together to make adventure games and
maze games.
- TRIVIA. Conducts a trivia question
and multiple choice answer game,
with topten scorers list, where the
score on each correct answer is
based on how quickly the answer is
given. Users can write trivia text
files for this module also.
- ADD-BBS-NUM. Users add BBS numbers
to a list that they can view.
- STATS LISTERS. Various modules that
display user activity, including a
LAST 51 CALLERS log.
When asked about her plans for OASIS
in the future, Miss Stocks responds:
-In the long term, I expect to see a
version, not an update, but perhaps
even OASIS IV, to be compatible only
with a DOS like SpartaDos 3.x and
higher. In the short term, my plans
involve splitting XBN into two boards.
The split will allow for a more full
and fair support of OASIS/RELIGION,
and ZMAG/ATARI. I invite everyone to
give the boards a call.-
Z-INNOVATORS distributes OASIS 3
software for $20.00 from the following
address:
Z INNOVATORS 1344 Park St.
Stoughton, MA 02072 Dept. 187
Answering Service Phone: 617-586-3385
BBS Phone Numbers: 617-770-0026
617-770-0197
For OASIS Sysop support call:
XBN-MISSION 617-770-0026
(PC Pursuitable MABOS node)
HELP BBS 918-251-5450
OASIS SYSOPS!! BONUS !
The $5.00 update fee to upgrade to
OASIS 3, is hereby waived and done
away with as of February 8th, 1988.
TREAT !
The February 3rd, 1988 UPDATE is
posted on XBN-MISSION at 617-770-0026.
Call and download your NEW UPDATE!
______________________________________
| -=2=- |Atari News Update
|_______|_____________________________
ATARI PRODUCT NEWS UPDATE: 1/27/88
(C) 1988 by Atari Corp.
May be reprinted only with this
notice.
MICROSOFT WRITE
In mid-January, the first shipments of
Microsoft Write arrived at Atari's
warehouse and were shipped to Atari
dealers.
This advanced word processor, with a
list price of $129.95, is a direct
port of Microsoft Word 1.05 from the
Macintosh. It features true
footnoting, a sophisticated variety of
page setup features, and the cleanest
mouse interface of any ST word
processor.
Microsoft Write fully supports GDOS.
Included with the program is GDOS
version 1.8, along with a variety of
proportional fonts. The fonts are
supported on the screen for a WYSIWYG
performance.
In addition to GDOS output, Microsoft
Write supports a wide variety of
common printers in their own text
fonts. Printer drivers can be edited
by the user to support virtually any
printer on the market.
Microsoft Write includes extras such
as Mail Merge, Glossary, Undo,
Clipboard, Ruler, and page format
changes throughout the document.
ATARI LASER PRINTER
The Atari SLM804 Laser Printer arrived
to authorized dealers beginning before
the new year. This 8-page-per-minute
system uses the TEC engine, a write-
white device which provides the
sharpest possible blacks. Dot density
is 300 dots per inch.
The SLM804 connects directly to any ST
or Mega computer via the DMA port.
Included is the SLMC804, which allows
additional DMA devices (such as hard
disk drives) to be plugged into the
DMA while the laser is attached.
The Atari Laser Printer's unique
design has the ST or Mega driving the
engine directly, without mandating
costly and slow electronics within the
laser. Even with only 512K of system
RAM, an ST can drive the engine in
Diablo emulation mode and for screen
dumps. The Diablo emulator supports
up to 8 type styles using GDOS fonts
(GDOS itself is not required).
Also included with the printer are 2
disks of GDOS fonts. These laser fonts
correspont to the screen fonts
provided with Microsoft Write. Various
point sizes are supported, from 6
point up to 48 point.
Existing software that takes advantage
of GDOS includes MS Write and Easy
Draw. Using Easy Draw, outputs make
full use of the 300 dpi resolution of
the printer for fine lines at any
angle, smooth fonts, and bit images
from scanners. Easy Draw with
Supercharger can output full pages of
text and graphics in well under a
minute -- recent tests averaged 20-30
seconds per page. Multiple copies of a
page take less time than the original
page.
The Atari Laser Printer has a list
price of $1999. Replacement toner
cartridges sell for $59.95, and
replacement drums list for $199.95. By
separating toner from drum,
replacement costs and price per page
come in lower than other laser
printing systems.
______________________________________
| -=3=- |Guest Commentary on Atari
|_______|_____________________________
by Dave Brehm
Being a great fan of Zmag, I read with
interest an article from a
conversation with the folks at Analog
on the recent Buy-out.
Being an avid 8-Bit'er, I was
understandably concerned over a
statement that Analog MAY drop the
Analog Magazine if the interest in 8
Bit drops.
As far as I am concerned, the Atari 16
Bit ST's are super fine machine, Don't
get me wrong, However people who still
slave away over the good old 800XL and
130XE's are either not interested in
the ST LIne at the moment or can't
afford one.
I for one am in the catagory of not
interested right now, as I feel the 8
BIT still has alot of potential. The
problem seems to be a lack of interest
by the Softwear companies NOT the
users.
Some of us use the machines for MORE
than Games and that is the area we are
hurting in.
Some examples, SYNFILE+ is a Real good
database, HOWEVER, why has it not been
updated to make use of the additional
memory..too lazy? I would love to be
able to load the Data into Ram disk
and manipulate it at a much faster
rate...impossible??..I don't think so.
That is just one example of many, of
ways to keep 8 bit alive.
Take people like DATAQUE and their
MTOS, here are people who must still
believe in 8 bit to write a dos that
will Multi-task...right on an 8 bit.
How about IMP Softwear and their SUPER
DATABASE 1-2-3. Excellent program that
write programs for you. I use it all
the time and have had conversation
with the folks who are taking some
suggestions and putting it in the
softwear, and told me that is there
was enough interest they would write
it to support the XE and XL Expanded
memory...
These are the kind of people we need
more of to keep the 8 bit alive, and
the users to support them. With the 8
Bit survival at stake...I for one
would like to go on record and ask all
user's to start talking up these
dependable machine again, get the User
groups Hyped up again...Get uploading
to your favorite BBS the exceptional
software in the public domain that is
out there and distribute it..Take the
time..we need the support. To the
third party programmers, keep working
up the GOOD stuff..I think the
potential of the 8 BIT hasn't even
been tapped yet. and Thanks to Ron and
Zmag for getting the word out.
I would be interested in hearing any
comments on the subject. I can be
reached on the MOUSE BBS at
219-674-9288.
______________________________________
| -=4=- |Plents Page
|_______|_____________________________
...NX-1000 Review...
by Eric Plent
The Star Micronics NX-1000 printer is
the next generation of fast,
affordable dot matrix printers from
Star. It is the successor to the Star
NX-10 printer (which was
discontinued), but still carries on
the quality I have come to expect from
Star.
There are four (4) different versions
of this printer. The most used version
(as far as I know) is the 1000 model.
It is also available as the 1000c
(with a direct connection to the
Commodore 64 computer), the 1000
Rainbow, and the 1000c Rainbow. The
Rainbow models are color printers that
offer multicolor printing for almost
every application.
FEATURES:
Starting with the front control panel,
there are four buttons and 10
indicator lights. The buttons are as
follows:
(from left to right)
NLQ Type Font Selection
Print Pitch Selection
Paper Feed
On/Off line
The NLQ font selection button controls
which of the four built-in fonts are
available while printing. They are
-Courier-, -Sanserif-, -Orator- and
-Italic-. You can also use any of the
above fonts in Pica, Elite, Condensed
and Proportional pitches (which are
selected from the next button over).
In total, it gives you a great
flexability in your printing. In
addition, you can change the font
style you are using WHILE PRINTING A
DOCUMENT! Simply press the On/Off line
button, select the font style and
print pitch you want with the other
selection buttons, and press the
On/Off line button again. It will
continue right were it left off
without missing a character.
Print speed is 144 characters per
second in Draft (default) mode, and 36
characters per second in any Near
Letter Quality mode.
I found the print very readable in all
modes, but I particularly liked the
Orator font for printing letters and
other documents. It is very difficult
to tell the Orator from the output of
a letter quality printer or a
typewriter, is so good.
The Star NX-1000 operates with full
IBM emulation mode, as well as Epson
LX800 emulation. This is selected with
the dip switches located under the
print ribbon.
I am currently using the NX-1000 with
my Atari 800XL and a 256K MIO from
ICD, Inc. Since the MIO has a printer
interface built in, I do not need an
Atari 850 or ICD P:R: Connection to
use it. However, I tested it with a
Graphix AT interface and it worked
flawlessly.
Both pin feed and single sheet
operation is supported. To save space,
the pin feeder is located in the back
of the machine under a lock-down
cover. Pin feed paper can be fed in
through the back, and single sheets
can be fed in through the top. In
fact, by moving a switch, you can
disable the pin feed operation and use
single sheets, without having to
remove the pin feed paper. I was very
impressed with that.
I hope I have given you some food for
thought if you are in the market for a
new printer. The NX-1000 is an
excellent printer, and I highly
recommend it.
Approximate Retail Price: $179-$200.
Eric Plent
StarBase I BBS (201)/938-6906
300/1200/2400 Zmag carrier!
______________________________________
| -=5=- |SP408/808 Review
|_______|_____________________________
As many of you know. There aren't any
cheap ways to do MultiLine stuff for
the Atari, or any other computer for
that matter. I mean, there are ways.
But, how good are they??
Well, the SP series, by NiteLite
system. Is one anwser to the question
-How am I gonna do this?-. It is a
serial modem interface. That has
everything you need built in. All you
need to do, is make up 4-8 cables. The
SP408, is 4 lines (That's 3 RS232
ports, plus 0). The names, SP stands
for. Serial Programmable.
The 408 is similair to the 808. The
only differance between the two, is
the 808 has more lines. The price for
the 408 is also less then the 808
($199/$349 respectfully).
It is also and intellegent interface.
It's not a multi-plexer, as Paul
Swanson has told me many times. It has
a 65C02 Microprocessor built in. So if
you know 65C02, you can do many things
inside the SP itself. And the only
thing you need your computer for (if
you are using code inside the SP) is
to load up the SP with your code.
There is 8K of RAM inside of it. So
there is lots of room for a simple
chat board. Also, you can write code
inside of it, to take some stress of
your main system.
I have worked with the SP. There are
no bugs in the OS from what I could
tell. However, there is no error
checking. So you can crash the SP by
sending it wrong commands. Oh yah,
commands.
The SP has about a dozen or so special
commands that it uses in what I like
to call 'SP Immediate mode', so you
don't need to have to actually go out
and scan the ports yourself. It does
it for you. It can run at all baud
rates from 50-19,200 BPS, with no
trouble at all, from what I have seen.
Currently he is change the ROM around.
So it's not 100% complete yet.
Although runable. I still see some
ideas for some good upgrades to the
OS, and am now giving Paul Swanson
some of my ideas. He is on REV 3.1 of
the ROM. And with the needs of some of
the boards, who knows where it will
stop. I have written several programs
for the SP (OmniChat 8-Bit and
OmniChat ST). So far, I haven't
encountered any problems with the SP
itself. Although somethings in it
could do for some changes.
But all in all, it's the best (and
ONLY) salution to the MultiLine needs
arising. I give the SP 4 Stars.
NiteLite Systems
PO BOX R
Billerica,Ma 01862
Imager, AfterImage NiteLite
617-273-3065
PS: There is a good example of the SP
at that Number running MultiLine
NiteLite for the ST.
______________________________________
| -=6=- |Best Of 1987 Survey Results
|_______|_____________________________
Compiled by Ron Kovacs
The following survey results were
captured from a few Oasis BBS systems
running the Best of 1987 Survey.
The survey was created from the
Best of 1987 Poll created in December
1986. All the nominees were listed
by system users. Then I compiled the
survey from the entries and created
the survey.
The highest amount of entries were
listed in the survey for the users
to vote on. The accumulations of
the systems captured, are included
here. A few of the questions have been
deleted because they contained
regional and local information which
is not of use in other areas.
Total amount of votes per question:
272
ZMAGAZINE BEST OF 1987 SURVEY
| Question Number 1 |
Choose Your Favorite Atari 8 Bit BBS.
0> Express BBS (not pro)
1> Oasis (all versions)
2> Carina I (not II)
3> FoReM 8 Bit
4> NiteLite
5> AMIS
6> BBCS
[#0] 47 [#1] 167 [#2] 38 [#5] 13
[#6] 07
Best BBS Program of 1987> Oasis BBS
| Question Number 2 |
Choose Your Favorite Atari 16 Bit BBS.
0> FoReM ST
1> Express ST
2> Michtron
3> BB/ST
[#0] 202 [#1] 56 [#2] 11 [#3] 03
Best 16 Bit BBS Program of 1987
>FoReM ST
| Question Number 3 |
Choose Your Favorite Printer.
0> Star Series
1> Epson Series
2> Atari Series
3> OkiData (not Okimate)
4> NEC Series
5> Juki
6> Okimate 20
7> Texas Instruments
8> Kiss Lazer Printer
9> Panasonic Series
[#0] 66 [#1] 89 [#2] 31 [#3] 12
[#9] 74
Best Printer of 1987> Epson Series
| Question Number 4 |
Choose Your Favorite Atari Corp
Product. Atari only!
0> Mega ST
1> XEP80
2> 130XE
3> 1040ST
4> 1050 Disk Drive
5> 520ST
6> SC1224
7> XF551
8> XMM801
9> SX212
[#0] 35 [#1] 11 [#2] 95 [#3] 13
[#4] 30 [#5] 88
Best Atari Corp Product of 1987> 130XE
| Question Number 5 |
Choose Your Favorite 8 Bit Game, PD or
Other.
0> Alternate Reality
1> Arkanoid
2> HardBall
3> Gauntlet
4> Superman
5> World Championship Karate
6> Ultima 4
7> Gemstone Warrior
8> Flight Simulator II
9> Fooblitzsky
[#0] 59 [#1] 23 [#2] 27 [#3] 54
[#5] 31 [#6] 54 [#8] 24
Best 8 Bit Game of 1987>Alternate
Reality
| Question Number 6 |
Choose Your Favorite 16 Bit Game, PD
or Other.
0> Pro Wrestling
1> Shanghai
2> Gauntlet
3> StarGlider
4> Flight Simulator II
5> Alternate Reality
6> Wizardy
7> The Bards Tale
8> Mercenary
9> Gridiron
[#0] 40 [#2] 29 [#3] 39 [#4] 28
[#5] 32 [#6] 26 [#7] 55 [#8] 23
Best 16 Bit Game of 1987>Bards Tale
| Question Number 7 |
Choose Your Favorite Bulletin Board
Service.
This question omitted because contents
were targeted at local area systems.
| Question Number 8 |
Choose Your Favorite Online Service.
0> GEnie
1> CompuServe
2> PC Pursuit
3> Delphi
4> Games Computers Play (Off Line)
5> The Source
6> Dow Jones
[#0] 64 [#1] 98 [#2] 54 [#4] 33
[#5] 11 [#6] 12
Best Online Service of 1987>CompuServe
| Question Number 9 |
Choose Your Favorite SysOp.
| Question Number 10 |
Choose Your Favorite Co-SysOp.
These 2 questions were targeted at
local area sysops and co-sysops so
they were deleted from the survey.
| Question Number 11 |
Choose Your Favorite Magazine, Online
or Printed media.
0> Analog Magazine
1> ZMagazine
2> Antic
3> Atari Explorer
4> ST-Log
5> STart
6> ST-World
7> Compute
8> ST-Express
9> TeleTalk
[#0] 19 [#1] 84 [#2] 109 [#3] 17
[#4] 18 [#5] 07 [#7] 14 [#9] 04
Best Magazine of 1987>Antic Magazine
| Question Number 12 |
Choose Your Favorite Programmer.
0> Keith Ledbetter
1> Tom Hudson
2> Ralph Walden
3> David Small
4> Matt Singer
5> Bill Teal
6> Phillip Price
7> Matthew Ratcliff
8> Jerry Horanoff
9> Bill Wilkinson
[#0] 65 [#1] 23 [#2] 26 [#3] 29
[#5] 19 [#6] 49 [#7] 12 [#8] 25
[#9] 24
Best Programmer of 1987>Keith
Ledbetter
| Question Number 13 |
Choose ICD's Best Product.
0> Multi I/O
1> P:R: Connection
2> SpartaDos Consrtruction Set
3> R-Time Cartridge
4> US Doubler
5> Rambo XL
[#0] 94 [#1] 27 [#2] 86 [#4] 49
[#5] 16
Best ICD Product of 1987> Multi I/O
| Question Number 14 |
Choose Your Favorite Modem.
0> Avatex 1200HC
1> Avatex 2400
2> XM301
3> Supra 2400
4> USR Courier 2400
5> SX212
6> Everex 2400
7> Hayes 1200
8> Capetronic 1200
9> SmartTeam 2400
[#0] 47 [#1] 67 [#2] 32 [#4] 38
[#5] 29 [#7] 40 [#9] 19
Best Modem of 1987>Avatex 2400
| Question Number 15 |
Choose Your Favorite Hard Disk System
or Drive.
0> Seagate ST213
1> Supra 8 Bit 20 Meg
2> Supra 16 Bit 20 Meg
3> Atari SH204
4> NEC
5> Control Data
6> Seagate ST225
7> Seagate ST251
8> Seagate ST138
9> Seagate ST125
[#0] 11 [#1] 109 [#2] 71 [#3] 09
[#4] 57 [#9] 15
Best HD System of 1987> Supra 8 Bit
20 Meg HD
______________________________________
| -=7=- |Editors Desk
|_______|_____________________________
As you can tell we have changed ZMag
once again. I hope you find this new
style a bit more pleasant to the eye-
balls. Leave me feeback should have
any questions.
The Kovacs Baby update still has us
waiting! The due date has been placed
at February 15, 1988.
The Syndicate BBS will be returning
March 1, 1988 or before. Already
scheduled to make a return to the
system is our old friend Rum-Runner.
A mailing is being put together to
those who left me their addresses on
the ZMag BBS. Look for it soon after
the arrival of the baby.
Thank you for supporting ZMag. Since
the BBS will be returning to the phone
lines in a few weeks, look for an
update next week. XBN will REMAIN the
headquarters for ZMagazine and will
be joined by the Syndicate as the
exclusive places to get ZMag FIRST.
Regional headquarters are being
established also.
Till next week will hopefully news of
the arrival....
______________________________________
|..<9>..>|Atari Basic Programming
|________|____________________________
...Part 6 of a continuing series...
LESSON 3 Version 1.13
(C) COPYRIGHT 1987 by Jackson Beebe
CONTENTS:
LOOPING, GOTO Statement, ON-GOTO
Statement, FOR-NEXT Statement.
This is Part 6 Lesson 3 of Learning to
program in Atari BASIC, brought to you
by Jackson Beebe. Contact me at the
address at the end of this lesson.
LOOPING:
Up to this point, our programs have
executed -straight down- when RUN.
This means execution began at the
lowest numbered line, and proceeded
sequentially until the last line was
executed. Straight down program logic
is very limiting, as each line may
only be used once, and no decisions or
branching may occur. Most importantly,
the program cannot -loop.- Looping,
or sending program control back
through earlier lines, is one of the
most powerful features of a computer.
It's what separates computers from
calculators.
For example, we could write a program
that converts Fahrenheit temperatures
to Centigrade, prints the output, then
-loops- back to the beginning of the
program to convert more data. This
would use the code over and over
again. Very handy. Try this program:
10 REM * TEMP CONVERSION *
20 ? -INPUT Centigrade temp -;
30 INPUT CTEMP
40 FTEMP=CTEMP*1.8+32
50 ? CTEMP;-=-;FTEMP;- Fahrenheit-
60 ?:?
70 GOTO 20
This lesson will present an
introduction to the concept of
looping, and covers the GOTO and the
FOR-NEXT statement.
GOTO Statement:
This is the simplest of all
UNCONDITIONAL TRANSFER statements.
It's format is:
80 GOTO 20
A line number, followed by the word
GOTO (some BASIC'S allow GO TO)
followed by the destination line
number. When encountered in a program,
control goes immediately to the
specified line number. (You'll receive
an error message if there is no such
number.)
An example of the GOTO is:
10 PRINT
20 PRINT -TYPE YOUR NAME-
30 DIM NAME$(15)
40 INPUT NAME$
50 PRINT:PRINT NAME$
60 GOTO 10
This program will loop forever,
prompting, printing your name,
prompting, etc. This is an INFINITE
LOOP, as was the temperature
conversion program earlier.
The GOTO statement is the subject of
much controversy in BASIC. Many
programmers feel it should NEVER be
used, as it allows terrible sloppy
programming, that defies tracing. For
example:
10 GOTO 60
20 PRINT -HI-
30 GOTO 50
40 END
50 GOTO 40
60 GOTO 20
BASIC doesn't -protect you from
yourself.- It will allow your programs
to wander aimlessly, and/or take wild
leaps, that are nearly impossible to
figure out. More structured languages
don't permit this. This feature of
BASIC is a mixed blessing. There are
times I find a GOTO pretty handy, e.g.
at the end of a menu. When you've
tested for every possible correct
input, and haven't found one, then it
must be an error, so you erase the
invalid entry from the screen and send
control back to the input to try
again, with a GOTO. It's clear enough
there.
Go easy on these, and don't use them
to fix a sloppy kludge that you've got
going, that REALLY needs to be
re-written into cleaner code. Please
don't give BASIC a bad name !!
ON GOTO Statement:
This is like the GOTO, in that it is
an UNCONDITIONAL transfer statement.
This has a built-in feature of sending
the program to one of several places,
depending on the value of some
variable. It has the syntax:
25 ON (variable) GOTO XX,YY,ZZ
If the variable named, has the value
1, control goes to line XX. If
variable = 2, control goes to line YY,
and to ZZ if variable = 3, etc.
For example, let's say we have a menu
like the one below, and we use a
variable named CHOICE to bring in our
input.
<1> Load a file
<2> Save a file
<3> Directory
<4> Quit to DOS
CHOICE > ?
Code would look like this:
5 REM ** MENU DEMO **
10 ? CHR$(125)
20 ? :? :? - <1> Load a file-
30 ? :? - <2> Save a file-
40 ? :? - <3> Directory-
50 ? :? - <4> Quit to DOS-
60 ? :? :- CHOICE > -;
70 INPUT CHOICE
80 ON CHOICE GOTO 150,200,250,300
90 etc
100 GOTO 70
110 etc
120 etc - -
900 END
This uses an INPUT statement to bring
in a value in CHOICE, either a 1, 2,
3, or 4. Depending on the value, it
sends the program to 4 different
places, line 150,200,250,or 300.
If CHOICE is 1, control will go to
line 150. If 2, then line 200. If 3,
then line 250, and if 4 then line 300.
If the value of the variable is 1,
then it goes to the first line #, if
2, it goes to the second, and so on.
These can string out to more choices
that you or I will probably ever need.
The destination line numbers don't
need to be in any order. For instance,
this is okay:
120 ON CHOICE GOTO 15,150,25,95,450
Very handy for menus, and small
numbers 1-6 or so. If CHOICE is not
exactly equal to one of these
integers, the program will -fall
through- the line. Sometimes you can
force large numbers down to low
integers by dividing, and taking the
INTEGER value, etc.
FOR-NEXT Statement:
This is used when you know you want to
-crank- a loop a certain NUMBER OF
TIMES (like looping 6 times to guess
the LOTTO number (6 digits) or by
using a variable to determine how many
times to loop.
We usually put a FOR and a NEXT
-around- code that we want to execute
a set number of times. For example:
50 FOR X = 1 TO 10
60 PRINT -SUPER-
70 NEXT X
80 END
This would -loop- from line 50 to 70,
10 times, printing SUPER each time.
The syntax is:
10 FOR (variable) = start# to finish#
...then our routines in here...
20 NEXT (variable)
FOR-NEXT loops count from the starting
number specified, to the ending
number. When you reach the ending
number, it will not loop back to the
FOR statement again, but will -fall
through- the NEXT statement to the
next lines of the program. The loop is
-finished.- For example:
25 FOR NUMBER = 1 TO 5
. . . . code. . . . .
55 NEXT NUMBER
or
25 FOR COUNT = -3 to 27
. . . . code. . . . .
95 NEXT COUNT
There's also an optional ending called
STEP, to specify how many numbers to
step each time you count. If you leave
it out, it steps 1 at a time by
default. It looks like this.
10 FOR X=1 TO 6 STEP 2
.......
90 NEXT X
This steps 2 at a time. This loop
would only run a total of 3 times
(X=1,X=3,X=5). X starts at 1, then is
3, then 5. (The next value would be 7,
and be greater than 6.) When the value
of the variable is greater than the
ending number, it DOESN'T execute the
code in the loop (between FOR and
NEXT), but goes to the next line AFTER
the NEXT statement. It -falls thru-
the FOR-NEXT loop.
FOR-NEXT loops may step from a higher
to a lower or negative number, by
specifying a larger starting than
ending number, and using a negative
STEP value. For example:
10 FOR NUM = 3 to 1 STEP -1
20 ? NUM
30 NEXT NUM
40 END
This would print a list of numbers
from 3 to 1. You may even step by
decimal values. We will use FOR-NEXT
in MOST programs we write for one
purpose or another.
EVERY FOR NEEDS A NEXT. They must
match up in number (3 of each, etc.)
Atari BASIC allows more NEXT than
FOR statements like:
125 FOR NUM = 1 to 50
130 IF NUM = 27 THEN NEXT NUM
135 IF NUM = 28 THEN NEXT NUM
140 IF NUM = 29 THEN NEXT NUM
145 PRINT NUM
150 NEXT NUM
160 END
This program just loops 50 times, and
prints the value of the loop variable
NUM each time, except when NUM equals
27, 28, or 29. For those values, the
NEXT NUM statements in lines 130-140
send control immediately back to the
FOR statement in line 125, not passing
through line 145's PRINT statement.
If you have a BASIC compiler, and try
to compile the above program (more on
compilers in much later lessons), it
probably will blow the compile, seeing
too many NEXT statements. This could
be fixed by changing lines 130-140
from saying NEXT NUM to saying GOTO
150. Just a handy household hack!
We usually put a FOR-NEXT loop
-AROUND- other code, to get the
program to do that code, a certain
number of times. The true power of the
FOR-NEXT loop comes from the fact that
it can use VARIABLES for the starting
and finishing number, as well as
numbers. This allows it to do
something like -check every letter in
a word.- To do that, we could write a
FOR-NEXT loop from 1 to the length of
the word. Lets assume we INPUT a word,
using the variable WORD$. Like this:
15 REM * DEMO *
20 DIM WORD$(20)
25 PRINT -Type in an uppercase word.-;
30 INPUT WORD$
35 FOR X = 1 TO LEN(WORD$)
40 IF ASC(WORD$(X,X)) < 65 OR ASC
(WORD$ (X,X)) > 90 THEN PRINT -**ERROR**-:END
45 NEXT X
50 PRINT -THIS WORD IS UPPERCASE-
55 GOTO 25
60 END
This program INPUTs a word to the
variable WORD$, and checks the ATASCII
code to see if it's right for
uppercase letters. More on ATASCII
later. Look in your manuals. All the
letters, numbers, punctuation, etc are
assigned numbers, i.e. A = 65. Type in
the program above, and try it. Type in
short words in uppercase, then in
mixed upper/lower case.
Now to be technical! (I know it's a
pain, but you need this one.) The
value of the loop variable (the one
specified in the FOR and the NEXT
statement) increments each time it
LEAVES the NEXT statement, and zooms
back up to the FOR. Again, the place
that the loop variable or counter, is
incremented, is as it leaves the NEXT
statement (line 45) and returns to the
FOR statement (line 35.)
A small programming trivia thing to
remember, is that the value of a
FOR-NEXT variable is always ONE
greater than the value of the loop,
after it finishes. See, it drops
though one last time when it's done,
and gets incremented a final time,
even though it's done looping.
Programs begin execution at the next
line after the NEXT, when the loop is
finished. Again, think of the FOR-NEXT
loop as -falling through- when
finished.
FOR-NEXT is frequently used for a
timer, to make the program sit there
and wait for a moment. For instance,
when printing an intro screen like
this:
10 ? CHR$(125)
20 ?:?:?:? -* * WELCOME TO * *-
30 ?:?:?:? - SNAZZO-
40 ?:?:? - by B. Mudflap-
50 FOR X = 1 TO 400:NEXT X
60 ? CHR$(125)
100 main body of program etc.
This would clear the screen, print
your introduction, wait there aprox.
10 seconds, then clear the screen and
begin the program. A larger value in
the FOR-NEXT loop will take longer to
count up to. Try these timers
yourself.
SUMMARY:
Up to this point, we know:
TWO WAYS TO LOOP:
1) GOTO statement
2) FOR-NEXT statement
Next lesson we'll learn the basic 3rd,
the IF-THEN statement, that tests and
loops or branches.
BLAST FROM THE PAST:
Do you know three ways to get data
into a program?
ANSWER: 1) the LET statement
2) the READ-DATA statement
3) the INPUT statement
------------------------------------
SAMPLE Problems:
PROBLEM 3
Write a program that prompts for input
in inches, and shows labeled output in
centimeters, using the formula 1 inch
= 2.54 centimeters.
When it finishes, it should loop back
and prompt for input to run again and
again. (Quit using BREAK key.)
PROBLEM 3A
Write a FOR-NEXT program that produces
the printout:
6 5 4 3 2 1 ZERO
PROBLEM 3B
Write a program that prints out all
the even numbers between 0 and 50.
PROBLEM 3C
Write a program that produces a table
of numbers, their squares, and their
square roots, using the format below.
The table MUST start at 10, and finish
at 1.
NUMBER SQUARED SQ. ROOT
10 100 3.3XXXX
9 81 3
8 64 2.XXXXX
. . .
. . .
1 1 1
This concludes Part 6 and lesson 3 of
Learning to Program in Atari BASIC. Be
sure to catch Part 7 Lesson 4 next
week.
Contact me at: Jackson Beebe
Prairie Data Fields 807 W. Hill St.
Urbana, IL 61801 or CompuServe
72550,317
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Syndicate Zmagazine Issue #92
(c)1988 Syndicate Publishing Company
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