Color Computers

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~~NOTOC~~
====== GETTING STARTED WITH COLOR BASIC ======

===== Front Cover =====
{{:gswcb-000.png|Getting Started With Color BASIC Front Cover}}

Radio Shack® Cat. No. 26-3191

GETTING \\
STARTED \\
WITH \\
COLOR \\
BASIC \\

TRS-80™ COLOR COMPUTER

===== Title Page =====

{{:gswcb-003.png|Getting Started With Color BASIC Title Page}}

GETTING \\
STARTED \\
WITH \\
COLOR \\ 
BASIC
===== Manual Copyright =====

//Getting Staried with COLOR BASIC: © 1980
Tandy Corporation, Fort Worth, Texas 76102
U.S.A. All Rights Reserved.//

Reproduction or use, without express written
permission from Tandy Corporation, of any
portion of this manual is prohibited. While reasonable
efforts have been taken in the preparation of
this manual to assure its accuracy, Tandy Corporation
assumes no liability resulting from any errors
or omissions in this manual or from the use of the
information obtained herein.

//TRS-80 Color Computer System Software: © 1980
Tandy Corporation and Microsoft. All Rights
Reserved.//

The system software in the Color Computer micro-
computer is retained in a read-only memory
(ROM) format. All portions of this system soft-
ware, whether in the ROM format or other source
code form format, and the ROM circuitry, are
copyrighted and are the proprietary and trade secret
information of Tandy Corporation and Microsoft.
Use, reproduction or publication of any portion of
this material without the prior written authorization
by Tandy Corporation is strictly prohibited.

10 9 8 7 6 5 4 3 2 1

===== Introduction =====

**INTRODUCTION**

This book is for those of you who don’t know anything about Computers, and would like to be
spared the long, technical explanations!

Using this as your guide, you'll be able to interact and enjoy your Computer right away. Later, you'll
probably want to read some of our thorough and detailed books. For now, though, the easiest way to
get started with your Computer is to use it and have fun doing it.

You'll find many of the things we have you do — especially in the first chapters — are games,.
songs, or other fun-type programs. This is not to say your TRS-80 can’t be used for practical
programs. It’s every bit as powerful as other computers its size. We start you off with the fun
programs because it’s the easiest way for you to feel at ease with your Computer. Once you feel it’s
truly an extension of yourself, you’ll find it much easier to write any kind of program you want.

So sit down and spend a couple of hours with it. Type away at it. Play with it. Try to make it do
strange things. In other words...get to feeling comfortable with it. There’s an infinite number of
things it can do for you.

===== To Get Started =====

//TO GET STARTED ...//


Connect your Computer by referring to the Chapters on “Installation” and “Operation”, and to
Figure 1 in your //[[TRS-80 Color Computer Operations Manual]]//((Corrected spelling of Operations Manual)).

Then power up your Computer:

  * Turn ON your television set
  * Select channel 3 or 4
  * Set the antenna switch to “COMPUTER”
  * Turn ON the Computer. The POWER button is on the left rear of your keyboard (when you’re facing the front).

This message should appear:

COLOR BASIC //v.r// \\
© 1980 TANDY \\
OK

(//v.r// is two numbers specifying which version and release you have).

If you don’t get this message, turn the computer on and off again. Adjust the
Brightness and Contrast on your T.V. set. Check all the connections. If you still
don’t get this message, refer to “Troubleshooting and Maintenance” in the
//[[TRS-80 Color Computer Operations Manual]]//.

Once you do get this message, you’re ready to begin.


===== How Do You Talk To A Computer =====

{{:gswcb-007.png|How Do You Talk To A Computer?}}

//HOW DO YOU TALK TO A COMPUTER?//

In this book, you'll learn how to talk to your Computer. That’s all programming is, by the way. Once
you learn how to communicate, you'll be able to get your Computer to do whatever you tell it. (well,
almost).
The Computer understands a language called COLOR BASIC. COLOR BASIC is form of BASIC —
Beginners All-purpose Symbolic Instruction Code. There are lots of computer languages. COLOR
BASIC just happens to be the language your Computer understands.

We'll introduce BASIC words in the order that it’s easiest to learn them. When you get mid-way in
the book, you might forget what one of the words means. If this happens, simply look up the word in
the back of the book or use your “[[Quick Reference Card]]” to find its meaning.

===== Table Of Contents =====

**TABLE OF CONTENTS**

**[[#CHAPTER 1]]: [[#MEET YOUR COMPUTER]]** \\
**[[#CHAPTER 2]]: [[#YOUR COMPUTER NEVER FORGETS (unless you turn it off...)]]** \\
**[[#CHAPTER 3]]: [[#SEE HOW EASY IT IS?]]** \\
**[[#CHAPTER 4]]: [[#COUNT THE BEAT]]** \\
**[[#CHAPTER 5]]: [[#SING OUT THE TIME]]** \\
**[[#CHAPTER 6]]: [[#DECISIONS, DECISIONS]]** \\
**[[#CHAPTER 7]]: [[#GAMES OF CHANCE]]** \\
**[[#CHAPTER 8]]: [[#SAVE IT ON TAPE]]** \\
**[[#CHAPTER 9]]: [[#COLOR YOUR SCREEN]]** \\
**[[#CHAPTER 10]]: [[#ONE FANTASTIC TEACHER]]** \\
**[[#CHAPTER 11]]: [[#HELP WITH MATH]]** \\
**[[#CHAPTER 12]]: [[#A GIFT WITH WORDS]]** \\
**[[#CHAPTER 13]]: [[#BEAT THE COMPUTER]]** \\
**[[#WHAT NOW?]]** \\

**[[#APPENDIXES]]** \\
**A** / //[[#MUSICAL TONES]]// \\
**B** / //[[#BASIC COLORS]]// \\
**C** / //[[#PRINT @ SCREEN LOCATIONS]]// \\
**D** / //[[#GRAPHICS SCREEN LOCATIONS]]// \\
**E** / //[[#ANSWERS TO EXERCISES]]// \\
**F** / //[[#SAMPLE PROGRAMS]]// \\
**G** / //[[#ERROR MESSAGES]]// \\
**H** / //[[#BASIC SUMMARY]]// \\


===== CHAPTER 1 =====

{{:gswcb-010.png|Introducing TRS 80 Meet Your Computer}}

INTRODUCING \\
TRS \\
80\\

**MEET YOUR COMPUTER **

===== Meet Your Computer =====

//MEET YOUR COMPUTER//

Is your Computer connected? Turned on? Ready to give it a first work-out?

In these first two Chapters, we’re going to introduce you to your Computer —
the way it thinks, some of its many talents, and even a couple of little quirks it
has. By the time you finish these chapters, you'll be ready to program ...
promise!

Type away on the keyboard and then press the (ENTER) key.

<box>
//All letters you type should be BLACK with a GREEN BACKGROUND. If they're reversed (green with a black background) press the (SHIFT) and (0) (zero) keys at the same time.//
</box>

Don’t worry about anything but the last line of type on your screen. It should
say:

  OK

OK is the Computer’s “prompt”. It’s telling you — “OK, enough foolishness ...
as soon as you are ready ...” (It patiently waits for your command.) //You// are
the Master — you can tell the Computer to do anything you wish.

Give it your first command. Type this exactly as it is below:

  PRINT "HI, I’M YOUR COLOR COMPUTER"

When you reach the end of the line on your screen, keep on typing. The last part
of the message will appear on the next line.

<box>
See the blinking light? You can type
something wherever you see it.
</box>
 
Now check your line. Did you put the quotation marks where we have them? If
you made a mistake, no problem. Simply press the (<-) key and the last
character you typed will disappear. Press it again and the next to the last will
disappear (...and so on and so on...).

Ready? This should be on your screen:
  OK
  PRINT "HI, I'M YOUR COLOR COMPUT
  ER"

Press the (ENTER) key and watch. Your screen should look like this:

  OK
  PRINT "HI, I'M YOUR COLOR COMPUT
  ER"
  HI, I'M YOUR COLOR COMPUTER
  OK

{{:gswcb-012.png|"Hi, I'm Your Color Computer!"}} \\
//“Hi, I’m Your Color Computer!”//

Your Computer just obeyed you by printing the message you had in quotes.
Give it another message to print. Type:

  PRINT "2"

Press (ENTER)... The Computer again obeys you and prints your next
message:

  2
  
Try another one:

  PRINT "2 + 2" (ENTER)

The Computer obeys you by printing((removed incorrect period from example screen output)):

  2 + 2

You probably expect a lot more than just an electronic mimic... like maybe
some answers! Well, try it without the quotation marks. Type:

  PRINT 2 + 2 (ENTER)
  
Much better. This time the Computer prints the answer:

  4

These quotation marks obviously must mean something. Try experimenting
some more with them. Type each of these lines:

  PRINT 5+4 (ENTER)
  PRINT "5+4" (ENTER)
  PRINT "5+4 EQUALS" 5+4 (ENTER)
  PRINT 6/2 "IS 6/2" (ENTER)
  PRINT "8/2" (ENTER)
  PRINT 8/2 (ENTER)

Have you come up with any conclusions on what the quotes do?

<box>
**“ ”**

//The Computer thinks of quotes like a
journalist does. If the message is in
quotes, the Computer must PRINT it
exactly as it appears. If it’s not in
quotes, the Computer can interpret it
by adding, subtracting, multiplying
or dividing it.//
</box>

<box>
//RULES ON STRINGS VS NUMBERS//

The Computer sees everything you type as //STRINGS// or //NUMBERS//. If it’s in
quotes, it’s a STRING. The Computer sees it //EXACTLY// as it is. If it’s not in quotes
it’s a //NUMBER//. The Computer will figure it out like a numerical problem.
</box>

==== A Color Calculator, No Less! ====

**A COLOR CALCULATOR, NO LESS!**

Any arithmetic problem is a snap for your Computer. Let it do some long
division. Type:

  PRINT "3862 DIVIDED BY 13.2 IS" 3862/13.2 (ENTER)

Let’s do a multiplication problem:

  PRINT 1589 * 23 (ENTER)

Notice that the Computer’s multiplication sign is an asterisk, rather than the
X sign which you’ve always used in math. This is because the Computer is such
a precise and literal creature that it would get the X multiplication sign mixed
up with the X alphabetical character.

Try a few more problems:

  PRINT "15 * 2 = " 15*2 (ENTER)
  PRINT 18 * 18 "IS THE SQUARE OF 18" (ENTER)
  PRINT 33.3/22.82 (ENTER)

<box>
//Notice how the Computer hands parts in quotes vs. the parts not in quotes.//
</box>

Now it’s your turn. Write two command lines which will print these two
problems as well as their answers:

  157 /.13.2 =
  95 * 43 =

<box>
//DO-IT-YOURSELF COMMAND LINES// \\
________________________________ \\
________________________________ \\
</box>

If you used “correct” command lines, this is what the Computer should have
printed on your screen:

  157 / 13.2 = 11.8939394
  95 * 43 = 4085

Ready for the answers:

  PRINT "157 / 13.2 =" 157/13.2
  PRINT "95 * 43 =" 95*43

<box>
//Actually there is no “correct” Com-
mand line. For that matter, there is no
correct way of handling your
Computer. There are many ways of
getting it to do what you want. Re-
lieved ... Good!//
</box>

==== It Has Its Rules... ====

** IT HAS ITS RULES...**

By now, the Computer has probably printed some funny little messages on
your screen. If it hasn’t, type this line deliberately misspelling((corrected mispelling of misspelling)) the
word PRINT:

  PRIINT "HI"

The Computer prints:

  ?SN ERROR

SN ERROR stands for “syntax” error. This is the Computer’s way of saying
“The command ‘PRIINT’ is not in my vocabulary ...I have no earthly idea
what you want me to do”. Anytime you get a SN error, it’s probably because you
made some kind of typographical error.

{{:gswcb-015.png|The Computer Has Its Rules}}

The Computer will also give you error messages when it //does// understand what
you want it to do, but you’re asking it to do something that it feels is //illogical// or
//impossible//. For instance, try this:

  PRINT 5/0 (ENTER)

The Computer prints:

  ?/0 ERROR

Which means “Don’t ask me to divide by 0 — that’s impossible!!”

If you get a strange error message you don’t understand, flip back to the
[[#Appendixes|Appendix]]. We’ve listed all the error messages there and what probably caused
them.

==== It's A Show Off, Too ====

**IT'S A SHOW OFF, TOO**

So far, all you’ve seen your Computer do is silently print on a green screen. But
your color Computer enjoys showing off. Type:

  CLS(3) (ENTER)

Now your screen is a pretty shade of blue with a green stripe at the top. Your
typed command told the Computer to clear the screen and print color number 3
— blue.

<box>
//If you don’t get the right colors, refer
to the color test in your Owner’s
Manual.//
</box?>

But why the green stripe? The Computer cannot type on a blue background.
Anytime it types something on the screen, it must type it on a green
background. Try typing some more characters. Notice that the Computer gives
these characters a green background also.

Colors other than green are for printing graphics illustrations. We'll spend lots
more time with this color capability later.

Press (ENTER) so that you get the OK prompt on your screen. Type:

CLS(7)

Now you should have magenta (pinkish purple) on your screen with a green
stripe at the top. Try some more colors if you like. Use any number from 0 to 8.
Your color Computer has nine colors. Each color has a numeric code.

{{:gswcb-016.png|Bug}}

//BUG: If you get a message saying MICROSOFT or an ?FC
Error message, it’s because you are using a number other than 0
through 8.//

Type CLS without a number code:
  
  CLS (ENTER)

If you don’t use a number code, the Computer assumes you just want a clear
green screen.

==== Computer Sound Off - One, Two... ====

**COMPUTER SOUND OFF — ONE, TWO...**

{{:gswcb-017.png|"Sound Off!"}} \\
“Sound Off!”

Type this:

  SOUND 1, 100 (ENTER)

If you don’t hear anything, turn up the volume and try again.

What you are hearing is 6 seconds of the lowest tone the Computer can hum.
How about the highest tone? Type:

  SOUND 255, 100

OK, so it’s got quite a hum-range...hope you're suitably impressed. Try some
other numbers. Hope you like the Computer’s voice (it’s the only one it’s got).

You want to know what the other number is for? (Or maybe you've already
found out). The second number tells the Computer //how long// to hum the tone.
You can use any number from 1 to 255. Try 1:

  SOUND 128, 1 (ENTER)

and the Computer will hum the tone for about 6/100ths of a second. Try 10:

  SOUND 128, 10 (ENTER)

The Computer sounds the tone for 6/10ths of a second. Try variations of both
numbers, but stick to numbers between 1 and 255.

{{:gswcb-016.png|Bug}}

//BUG: Again, if you get an ?FC Error message, it’s because you
are using a number other than 1 through 255.//

==== One More Thing... ====

**ONE MORE THING...**

Press the (SHIFT) and (0) (zero) keys, holding both down at the same time. Now
type some letters. The letters you type should now be //green// on a //black
background//. If they’re not, try it again pressing (SHIFT) slightly before
pressing (0). Be sure to hold both keys down at the same time.

Now, with the colors “reversed”, press (ENTER) and then type this simple com-
mand line:

  PRINT "HI" (ENTER)

The Computer gives you an ?SN ERROR. It doesn’t understand the command.

Press the (SHIFT) and (0) characters again and type some letters. They should
be back to normal: //black// with the //green background//. Press (ENTER) and type
the same command line again. This time, it'll work.

We just wanted to show you this in case you ever press (SHIFT) and (0) by a
mistake. The computer can’t understand any commands you type with re-
versed colors. If you ever find you’re typing with these reversed colors, press
the (SHIFT) and (0) keys to get the colors back to normal.

<box> 
//Curious about the reversed colors?
They're for people with a printer. The
printer will print everything typed in
reversed colors as lower case letters.//
</box>


**LEARNED IN CHAPTER 1**

^ BASIC WORDS ^ KEYBOARD CHARACTERS ^ CONCEPTS ^
| PRINT | (<-) | string vs. numbers |
| SOUND | (ENTER) | error messages|
| CLS | | |

We'll put a list like this at the end of each chapter. It'll help you make sure you
didn’t miss anything.

NOTES:

===== CHAPTER 2 =====

{{:gswcb-019.png|Your Computer Never Forgets}}

//CHAPTER 2//

**YOUR COMPUTER NEVER FORGETS** \\
**(...unless you turn it off... )**

===== Your Computer Never Forgets =====

//YOUR COMPUTER NEVER FORGETS// \\
//(. . . unless you turn if off . . .)//

One of the things that makes your Computer so powerful is its ability to
remember anything you ask it to. To make the Computer remember the
number 13, type this:

  A = 13 (ENTER)

Now type anything you want to confuse the Computer. When you’re done,
press (ENTER). To see if the Computer remembers what A stands for, type:

  PRINT A (ENTER)

Your Computer will remember 13 as long as you have it //on// ... or until you do
what we’re going to do next. Type:

  A = 17.2 (ENTER)

Now if you ask it to PRINT A, it will print the number 17.2.

This is what just happened in your Computer’s memory:

{{:gswcb-021.png|Your Computer's Memory}}

You don’t have to use the letter A. You may use any letters from A to Z. (Asa
matter of fact, you can use any //two// letters). Try typing this:

  B = 15 (ENTER)
  C = 20 (ENTER)
  BC = 25 (ENTER)

Have it print all your numbers. Type:
  PRINT A, B, C, BC

To get it to remember a //string// of letters or numbers, put a dollar sign next to the
letter. Type:

  A$ = "TRY TO:"
  B$ = "REMEMBER"
  C$ = "THIS YOU"
  BC$ = "GREAT COMPUTER"

Let’s see how sharp your Computer is. Type:
PRINT A$, B$, C$, BC$

<box>
{{:gswcb-022-01.png|Dollar Sign}} \\
//To the Computer, a dollar sign means
it’s a string.//
</box>

Computer types call all these letters //variables//. So far, we’ve used these
variables:

{{:gswcb-022-02.png|Your Computer's Memory}}

YOUR COMPUTER'S MEMORY

NUMBERS \\
A -> 17.2 \\
B -> 15 \\
C -> 20 \\
BC  -> 25

CHARACTERS \\
A$ -> "TRY TO" \\
B$ -> "REMEMBER" \\
C$ -> "THIS YOU" \\
BC$ -> "GREAT COMPUTER"

Try spot checking these variables to see if the Computer has remembered your
information properly. For instance, type:

  PRINT BC (ENTER)

To see if BC still contains 25.

<box>
//Try to set the computer to remember a
letter we haven’t used yet. What hap-
pens ... interesting...//
</box>

You can think of these variables as little boxes where you can store your
information. One set of boxes is for //strings//; the other set’s for //numbers//. You use
these variables to label each box.

==== THE COMPUTER IS FUSSY ABOUT ITS RULES ====

<box>
//Like we said before, the Computer has
it’s rules and might get a little fussy
with you if you don’t play by them.//
</box>

Do you think the Computer will accept these lines:

  D = "6" (ENTER)
  Z = "THIS IS STRING DATA" (ENTER)

With both of these lines, the Computer responds with ?TM ERROR. It’s telling
you you've got to play according to its rules.

<box>
//TM stands for Type MisMatch error.
It means you didn’t go by the rules.//
</box>

These are the rules you ignored:

<box>
//RULES ON STRING DATA//

(1) Any data in quotes is //STRING DATA//

(2) //STRING DATA// may only be assigned to variables
//WITH A $ SIGN//
</box>

To obey the Computer’s rules, we have to put a dollar sign after D and Z. Type:

  D$ = "6" (ENTER)
  Z$ = "THIS IS STRING DATA" (ENTER)

which the Computer accepts.
Do you think the Computer will accept this?

  D$ = 6 (ENTER)

These are the rules that this command ignored:

<box>
//RULES ON NUMERIC DATA//

(1) Numbers not in quotes are //NUMERIC DATA//

(2) Numeric data can only be assigned to
variables //WITHOUT A $ SIGN//
</box>

Type this, which the Computer will accept:

  D = 6 (ENTER)
  Z = 12 (ENTER)

You have now added this to your Computer’s memory.

{{:gswcb-024.png|Your Computer's Memory}}
 
YOUR COMPUTER’S MEMORY

NUMBERS \\
D -> 6 \\
Z -> 12

STRINGS \\
D$ -> "6" \\
Z$ -> "THIS IS STRING DATA"

Now you can do something interesting with these letters. Type:

PRINT D * 2 (ENTER)

The Computer prints the product of D times 2.

<box>
//The computer remembers that D = 6.//
</box>

Try this line:

 PRINT Z/D

The Computer prints the quotient of Z divided by D.

Would this work:

  PRINT D$ * 2 (ENTER)

Did you try it? This makes the Computer print the same ?TM ERROR. It
//cannot multiply string data//.

Cross out the commands that the Computer will reject:

<box>
//EXERCISE WITH VARIABLES//

F = 22.9999999 \\
M = "19.2" \\
DZ$ = "REMEMBER THIS FOR ME" \\
M$ = 15 \\
Z = F + F \\
</box>

Finished? This is what the Computer will accept.

  F = 22,9999999
  DZ$ = “REMEMBER THIS FOR ME”
  Z=F+F

<box>
//RULES ON VARIABLES//

You may use any two characters from A-Z for a variable.
If you want to assign it string data, put a dollar
sign after it. Otherwise, it can only hold numeric data.
</box>

**LEARNED IN CHAPTER 2**

^ CONCEPTS ^
| Variables |
| String vs. Numeric Variables |

Now that you’ve learned how the Computer thinks it will be easy to write some
programs. But before going to the next chapter, how about a break?

NOTES:

===== CHAPTER 3 =====

{{:gswcb-028.png?direct|SEE HOW EASY IT IS?}}
 
 
==== SEE HOW EASY IT IS? ====

Type:
  NEW (ENTER)

This is just to erase anything that might be in the Computer’s “memory”.

Now type this line: Be sure you type the number 10 first — that’s pretty
important.

  10 PRINT “HI, I’M YOUR COLOR COMPUTER”

Did you press (ENTER)? Nothing happened, did it? Nothing that you can see, that
is. What you just did is type your first program. Type:

  RUN

The Computer obediently runs your program. Type RUN again and again to
your heart’s content. The magic machine will run your program anytime you
wish, as many times as you wish.

Since that worked so well, let’s add another line to the program. Type:

  20 PRINT “WHAT IS YOUR NAME?”

<box>
//If you make a mistake after press-
ing// (ENTER)//, simply type the line
over again.//
</box>

Now type:

  LIST

Your Computer obediently LISTs your entire program. Your screen should
look //exactly// like this:

  10 PRINT “HI, I’M YOUR COLOR COM
  PUTER”
  20 PRINT “WHAT IS YOUR NAME?”

What do you think will happen when you RUN this? Try it. Type:
  RUN

The Computer prints:

  HI, I'M YOUR COLOR COMPUTER
  WHAT IS YOUR NAME?

Answer the Computer’s question and then press (ENTER) ........ What?
There’s that SN Error. The Computer didn’t understand what you meant when
you typed your name. In fact, the Computer can’t understand anything unless
you talk to it in its own way.

So let’s use a word the Computer understands — INPUT. Type this line:

  30 INPUT A$

This tells the Computer to stop and wait for you to type something, which it
will label as A$. Add one more line to the program:

   40 PRINT “HI, ” A$

Now list the program again to see if yours looks like mine. Type:

  LIST (ENTER)

Your program should look like this:

  10 PRINT “HI, I'M YOUR COLOR COM
  PUTER”
  20 PRINT “WHAT IS YOUR NAME”
  30 INPUT A$
  40 PRINT “HI, ” AS

Can you guess what will happen when you RUN it? Try it:
  RUN

That worked well, didn’t it? This is probably what happened when you ran the
program (depending on what you typed as your name):

  HI, I'M YOUR COLOR COMPUTER
  WHAT IS YOUR NAME?
  ? JANE
  HI, JANE

RUN the program again using different names:

{{:gswcb-031.png?direct|Running with different names}} 

The Computer doesn’t care what you want to call yourself. Here’s what line 30
did to your Computer’s memory each time you ran the program. (Assuming you
gave it the same names we did):

{{:gswcb-032-01.png?direct|Your computer's memory}}

{{:gswcb-032-02.png?direct|Name in lights}}

<box>
To delete a program line, simply type
and (ENTER) the line number. For
example:

50 (ENTER)

erases line 50 from the program.
</box>

There’s an easier way to run your program over and over without having to
type the RUN command. Type this line:

  50 GOTO 10

Now RUN it....... the program runs over and over again without stopping.
GOTO told the Computer to go back up to line 10:

  10 PRINT “HI, I'M YOUR COLOR COMPUTER™
  20 PRINT “WHAT IS YOUR NAME”
  30 INPUT A$
  40 PRINT “HI, ” A$
  50 GOTO 10

Your program will now run perpetually, because every time it hits line 50, the
Computer goes up to line 10 again. We call this a “loop”. The only way you can
stop this endless ioop is by pressing the (BREAK) key.

==== SPOTLIGHT YOUR NAME ====

Change line 50 so we can give your name the kind of attention it deserves. How
do we change a program line? Simply by typing it over again, using the same
line number. Type:

  50 GOTO 40

This is what the program looks like now:

  10 PRINT “HI, I'M YOUR COLOR COMPUTER”
  20 PRINT “WHAT IS YOUR NAME”
  30 INPUT A$
  40 PRINT “HI, ” A$
  50 GOTO 40

Type RUN and watch what this loop does. Press the (BREAK) key when you’ve
seen enough.

There’s a big change we can make simply by adding a comma or a semicolon.
Try the comma first. Type line 40 again, but with a comma at the end:

  40 PRINT A$,

<box>
//We're leaving out the "HI, " part this time.//
</box>

RUN the program ..... The comma seems to print everything in two
columns.

Press (BREAK) and try the semicolon. Type:

  40 PRINT A$;

<box>
//Remember, if you make a mistake on one ofd the lines, simply type the line over again.//
</box>

and RUN... . You probably won’t be able to tell what it’s doing until you press
BREAK). See how the semicolon crams everything together?

<box>
//RULES ON PRINT PUNCTUATION//

This is how punctuation at the end of a PRINT line makes the Computer PRINT:
(1) a //COMMA// makes the Computer //PRINT// in columns. \\
(2) a //SEMICOLON// makes the Computer cram the //PRINTing// together. \\
(3) //NO PUNCTUATION// makes the Computer //PRINT// in rows.
</box>


==== COLOR/SOUND DEMONSTRATION ====

Let’s play around some more with your Computer’s sound and color abilities.
First clean out its memory. Remember how?

<box>
//NEW (ENTER) ... wish mine worked that easily!//
</box>
   

Now enter this program:

  10 PRINT “TO MAKE ME CHANGE MY TONE”
  20 PRINT “TYPE IN A NUMBER FROM 1 TO 255”
  30 INPUT T
  40 SOUND T, 50
  50 GOTO 10

RUN through this program to get a sampling of some of the Computer’s tones.

{{:gswcb-016.png?nolink&200|BUG}}

//BUG: If you get a ?FC Error when you run this program, it’s
because you used a number other than 1 through 255. This error,
like all errors, will make the Computer stop RUNning the program.//
 

What would happen if we changed line 40 to:

  40 SOUND 50, T

//HINT: Look back in Chapter 1 where we talk about SOUND.//

---

Did you figure it out? By making this change, the Computer hums the same
tone every time, but hums it for a different length of time, depending on the
number you type in.

Press (BREAK) first and then erase this program by typing NEW. Now see if you
can write a program, similar to the one above, to make the Computer show a
color you ask for. Remember, there are 9 colors, 0 through 8.

<box>
//DO-IT-YOURSELF PROGRAM//

</box>

//HINT: Line 40 could be://
  40 CLS(T)

This is our program:

  10 PRINT “TO MAKE ME CHANGE MY COLOR”
  20 PRINT “TYPE A NUMBER BETWEEN 0 AND 8
  30 INPUT T
  40 CLS(T)
  50 GOTO 10

==== ADD POLISH TO THE PROGRAM ====

Professional programmers would think that pressing the key was a
rather sloppy way of getting the program to stop running. Why not get the
Computer to politely ask us if we are ready to end it? Change Line 50 in the
above program to:
   

  50 PRINT “DO YOU WANT TO SEE ANOTHER COLOR”

<box>
//Press (BREAK) before typing the line.//
</box> 

and add these lines:

  60 INPUT R$
  70 IF R$ = “YES” THEN 20

and RUN the program ... Type YES and the program will keep on running.
Type anything else and the program will stop.

This is what the program looks like:


{{:gswcb-036.png?direct|R$=yes}}

Let’s look at what these new lines did:

Line 50 simply printed a question.

Line 60 told the Computer to stop and wait for our answer -- R$.

Line 70 told the Computer to go back to line 20 //IF// (and only //IF//) your answer
(R$) was //YES//. If not, the program simply ended since there are no more lines in
the program.

<box>
//Don't worry about this IF/THEN right now. We'll be devoting a whole chapter to it later.//
</box>

You’ve covered a lot of ground in this chapter. Hope we’re just whetting your
appetite for more to come.

Don’t worry if you don’t understand everything perfectly yet. Just enjoy using
your Computer.

^ LEARNED IN CHAPTER 3 ^^^
| BASIC WORDS | CONCEPTS | KEYBOARD |
| Characters | How to Change and Delete a Program Line | (BREAK) |
| NEW | | |
| INPUT | | |
| GOTO | | |
| RUN | | |
| PRINT, | | |
| PRINT; | | |
| LIST | | |
| IF/THEN | | |


NOTES:

===== CHAPTER 4 =====

{{:gswcb-038.png|Count The Beat}}
 
==== COUNT THE BEAT ====

In this Chapter we are going to do some experimenting with Computer sound
effects. To do this, we have to first teach the Computer how to count.

<box>
//The logic of this will become clear later.//
</box>

Type this:

<box>
//Remember to type NEW (ENTER) before typing a new program.//
</box>

  10 FOR X = 1 TO 10
  20 PRINT "X = " X
  30 NEXT X
  40 PRINT "I HAVE FINISHED COUNTING"

RUN the program.

RUN the program several times, each time replacing line 10 with one of these
lines:

  10 FOR X = 1 TO 100
  10 FOR X = 5 T0 15
  10 FOR X = -2 T0 2
  10 FOR X = 20 TO 24

Do you see what FOR and NEXT are making the Computer do? They are
making it count. Let’s study the last program we suggested you try:

  10 FOR X = 20 TO 24
  20 PRINT "X = " X
  30 NEXT X
  40 PRINT "I HAVE FINISHED COUNTING"

Line 10 tells the Computer that the first number should be 20 and the last
number should be 24. It uses X to label these numbers.

Line 30 tells the Computer to keep going back up to line 10 for the next
Number—the NEXT X—until it reaches the last number (24).

Look at line 20. Since line 20 is between the FOR and NEXT lines, the
Computer must PRINT the value of X every time it counts:

  X = 20
  X = 21
  X = 22
  X = 23
  X = 24

{{:gswcb-040.png|Numbers}}

Add another line between FOR and NEXT:

  15 PRINT "... COUNTING ..." 

and RUN it. With every count, your Computer executes any lines you choose to
insert between FOR and NEXT.

Write a program which will make the Computer print your name 10 times.


//HINT: The program must count to 10.//

<box>
//DO-IT-YOURSELF PROGRAM 4/A //

</box>

Write a program which will print the multiplication tables for 9 (9*1 through
9*10).

<box>
//DO-IT-YOURSELF PROGRAM 4/B //

</box> 

//HINT: PRINT 9*X is a perfectly legitimate program line.//


Write a program which will print the multiplication tables for 9*1 through
9*25.

<box>
//DO-IT-YOURSELF PROGRAM 4/B //

</box> 

//HINT: By adding a comma in the PRINT line, you can get all the problems and results
on your screen at once.//

FIXME everything after this point


"2, 4, 6, 8...”

Finished? These are our programs:

Program 4/A Program 4/B Program 4/C
10 FOR X = 17010 10 FOR X = 17010 10 FOR X = 1: T0.25
20 PRINT “THOMAS” 20 PRINT “9*”X“="9*X = 20 PRINT “9*”X“=”9*X,
30 NEXT X 30 NEXT X 30 NEXT X

COUNTING BY TWOS

Now we'll make it count a little differently. Erase your program by typing
NEW and then type our original program, using a new line 10:

10 FOR X = 2 TO 10 STEP 2

20 PRINT “X= “ X

30 NEXT X

40 PRINT “I HAVE FINISHED COUNTING”

RUN the program. . . Do you see what the STEP 2 did? It makes the Computer
count by 2’s. Line 10 tells the Computer that:

@ the first X is 2

@ the last X is 10
oo AND STEP 2... .

@ all the Xs between 2 and 10 are 2 apart... that is 2, 4, 6, 8, and 10.
(STEP 2 tells the Computer to add 2 to get each NEXT X.) '

To make the Computer count by 3’s, make all the Xs 3 apart. Try this for line
10:

10 FOR X = 3TO 10 STEP 3

RUN the program. It should print this on your screen:

X = 3
X = 6
Xx =9
 

It passed up the last X (10) because 9 + 3 = 12. Try afew more FOR... STEP
lines so you can see more clearly how this works:

10 FOR X = 5 TO 50 STEP 5
10 FOR X = 10 TO 1 STEP-1
10 FOR X = 1 TO 20 STEP 4

COUNTING THE SOUNDS

Now that you've taught the Computer to count, you can add some sound. Erase
your old program and type this:

10 FOR X = 1 TO 255
20 PRINT “TONE ” X
30 SOUND X, 1

40 NEXT X

This program is making the Computer count from 1 to 255 (by ones). Each time
it counts it does what lines 20 and 30 tell it to do:

e It PRINTs X, the current count (Line 20)
@ It SOUNDs X’s particular tone (Line 30)

For example:

@ the first time the Computer got to FOR, in line 10, it made X equal to 1.
@ then it went to line 20 and printed 1, the value of X.

@ then, line 30 had it SOUND tone #1.

@ then it went back up to line 10 and made X equal to 2

® etc.

What do you think the Computer will do if you make this change to line 10:

TO POR. X =. 255: TO 2 STEP —s

Did you try it? Using STEP, change line 10 so the Computer will sound tones
from:

 

 

39
 

40

 

(1) the bottom of its range to the top, humming every tenth note.
(2) the top of its range to the bottom, humming every tenth note.
(3) the middle of its range to the top, humming every fifth note.

 

Ready for the answers?

1° '255- STEP 10

10 FOR X =
10 FOR X = 255 TO 1 STEP —10
10 FOR X = 128 TO 255 STEP 5

Now see if you can write a program which makes the Computer hum:

-(1)_ from the bottom of its range to the top, and then
(2) from the top of its range back to the bottom

 

The answer is in the back of this book.
 

BUT CAN IT SING?

Yes. Although your Computer is slightly off pitch, it can warble out most
songs. The next chapter will show you how to teach it some of your favorite

songs.

FOR) c:') F045 STER
NEXT

NOTES:

 

 

 

 

 

 

 

 

 


===== CHAPTER 5 =====

 

 

 

SING OUT THE TIME

 
SING OUT THE TIME

You’re now ready to show your Computer how to do two things: tell time and
sing (... well, as good as the Computer can sing. . .). Since they are actually
closely related — especially to your Computer! — we're covering them both in
the same Chapter.

Begin by typing this:

10 FOR Z = 1 TO 460 * 2
20 NEXT Z
30 PRINT “I COUNTED TO 920”

RUN the program. Be patient and wait a couple of seconds. Two seconds, to be
precise. It takes your computer 2 seconds to count to 920.

Lines 10 and 20 set a timer pause in your program. By making the Computer
count to 920, it keeps the Computer busy for 2 seconds.

As you can see, this gives us the makings of a stopwatch. Erase the program,
and type this:

10 PRINT “HOW MANY SECONDS”
20 INPUT S

30 FOR Z = 1 TO 460*S

40 NEXT Z

50 PRINT S “ SECONDS ARE UP!!!”

43
 

RUN it, inputting the number of seconds you want timed on your stopwatch.

It would be nice if the stopwatch could sound some kind of alarm. Add some
lines to the end of the program to make it sound an alarm.

 

Here’s the program we wrote:

10 PRINT “HOW MANY SECONDS”
20 INPUT S

30 FOR Z = 1 TO 460 * S$
40 NEXT Z

i ee Le 50 PRINT S “ SECONDS ARE UP!!!”
This is how computerized timers — i‘< FOR T = 120 TO 180

  

Revie et eens 70 SOUND T, 1
80 NEXT T

>90 FOR T = 150 TO 140 STEP -]
100 SOUND T, 1
110 NEXT T

120 GOTO 50
44
 

Notice the GOTO line we added at the end of the program. This is so the
message would print and the alarm would keep ringing over and over again

until the nervous programmer must press the (BREAK) or (SHIFT keys to turn
it off.

COUNTING WITHIN THE TIME

Before we go any further on the clock, we’re going to have the Computer keep
count within the time. This concept will become very clear to you shortly.

Type this new program:

10 FORX = 1T03
20!) PRINT “Xam 1K

30 FORY = 1T02
40 (PRINT, VS 40-¥
50 NEXT Y

60 NEXT X

RUN it ... This should be on your screen:

X=1
Y=1
Y=2
X= 2
y 1
Y 2
X = 3
Y=1
Y=2

Call it a count within a count or a loop within a loop — whatever you prefer.
Programmers call this a “nested loop”. This is what the program does:

I. It counts X from 1 to 3. Every time it counts
X, it does these things:

A. It PRINTs the value of X

Notice the comma in line 40. Try it
without the comma. The comma

makes “Y = ” Y PRINT on the next
column.

 

45
 

With this groundwork, it is easy to make a full fledged clock:

10

20

30

~

40

60

70

 

a

80

 

90

 

(((

0 TO 23

FOR H

FOR M

0 10 59

FORS = 07059

CLS

PRINT H""M":"S

SOUND 150, 2

FOR T = 1 TO 375

NEXT T

NEXT S

100 NEXT M

110 NEXT H

Here’s an outline of what the Computer does in this program:

48
 

L It counts the hours from 0 to 23. (Line 10)
Every time it counts a new hour:

A. It counts the minutes from 0 to 59. (Line 20) |
Every time it counts a new minute:

1. It counts the seconds from 0 to 59. (Lines 30 and 90)
Every time it counts a new second:

a. It CLears the Screen. (Line 40)
b. It PRINTs the hour, minute, and second. (Line 50)

c. It SOUNDs a tone. (Line 60)
d. It pauses long enough for one second to pass. (Lines 70 and 80)

 

2. When it finishes counting all the 59 seconds,
it goes back up to line 20 for the next minute. (Line 100)

B. When it finishes counting all the 59 minutes,
it goes back up to line 10 for the next hour. (Line 110)

 

Il. When it finishes counting all hours (0-23), the program ends.

Between lines 90 and 100 you can add some tones which will sound every
minute. Write a program which does this.

49

 
50

 

Write a program which makes your Computer show each of its nine colors for 1
second each:

 

But who said this Computer could
make the Opera?

If you’re a real music lover, you will
probably want to purchase RADIO
SHACK’s “MUSIC” — Catalog num-

_ ber 26-3151. Then you will be able to
_ compose songs on your Computer
_ with perfect pitch.

The answers to both of these programs are in the back.

FOR A COMPUTER, IT SINGS GREAT!

Now back to teaching your Computer how to sing. Flip back to the Appendix.
We have a table, “Musical Tones”, which shows the Computer’s tone number
for each note on the musical keyboard. For example, the Computer’s tone
number 89 corresponds to “middle C”.

Unfortunately, your Computer can’t exactly match most of the musical tones.
That’s why the Computer sings a little off key. . . But to those without perfect
pitch, it can still sound very close to music.
 

Type this:

20 SOUND 125, 8
30 SOUND 108, 8
40 SOUND 89, 8

RUN the program. It is the first three notes of . . .well you know that, great

piece!

To get these first three notes to play over again, we can put a FOR/NEXT loop

in the program:

10
20
30
40
50

FOR X = 11702
SOUND 125, 8
SOUND 108, 8
SOUND 89, 8
NEXT X

Now RUN the program again. It’s missing a pause, isn’t it? It’s easy enough to
put a timer pause in the program. Add these lines:

44
46

FOR Y = 1 TO 230
NEXT Y

and RUN it again. Now it’s beginning to sound like the real thing!

 

51
 

Here is a program that gets through the first two phrases:

 

52

Three blind mice

See

how they

 

run

i

eB

 

30

40

44
46

\ 50

fia
70
80
90
100

Co

 

130

THREE BLIND MICE

FOR X = 1170 2
SOUND 125, 8
SOUND 108, 8
SOUND 89, 8

FOR Y = 1 TO 230
NEXT Y

NEXT X

FOR X = 1T0 2
SOUND 147, 8
SOUND 133, 4
SOUND 133, 4
SOUND 125, 8

FOR Y = 1 TO 230
NEXT Y

NEXT X

“Three”
blind’
‘“mice”’

(pause)

“See”
“how”
“they”
Yeun”!

(pause)

Finish the song, if you like. Or write a better one. Your Computer songs can
certainly jazz up any program.
 

 

 

 

 

 

 

 

 

 

NOTES:

Nested Loops

 

 

 

 

 

 

 

 

 

 


===== CHAPTER 6 =====

      
  
  

A DOES NOT
EQUAL 5S

—~aeees

~—

ae

 

DECISIONS, DECISIONS. ..

 
ote.
$%~
eo

DECISIONS, DECISIONS. . .

Here’s an easy decision for the Computer:
(1) IF you type RED ... THEN make the screen red
.or
(2) IF you type BLUE ... THEN make the screen blue
Easy enough? Let’s make the Computer do it. Type this program:

10 PRINT “DO YOU WANT THE SCREEN RED OR BLUE?”

 

 

20 INPUT C$

30 IF C$ = “RED” THEN 100 es Don’t be confused by the arrows or the

40 IF C$ = “BLUE” THEN 200 Rewecs between Ree lines. We
y % Just put them in to illustrate the flow

100 CLS(4) <@ ~ of the program.

110 END . tee

200 CLS(3) <

RUN the program several times, typing both RED and as

Let’s see what the program is doing:
56

 

A

IF you type RED... THEN ...

Line 30 sends your program down to line 100. Line 100 makes your screen red.
At this point, we have to stop the Computer from going on to line 200.

Line 110 does just that. It ends your program right there... Once the
Computer gets to line 110, it will never make it to 200.

...On the other hand...
IF you type BLUE... THEN...

Line 40 sends your Computer down to line 200, which makes your screen blue.
We do not have to put END on the next line. Since line 200 is the last line in the
program, the Computer will end there anyway.

What happens if you type something other than RED or BLUE? Try running
the program, typing GREEN in response to the Computer’s question.

It makes the screen RED, right? Do you know why?

HINT: IF the condition is not true, the THEN part of the line is
ignored and the Computer proceeds to the next program line.

There are two lines you could add to make the Computer ask you to type your
answer again if you don’t type RED or BLUE. We will give you the two lines,

and let you figure out where to put them in the program:
them in the program:

 

insert the line numbers

 
 

HINT: The lines must come AFTER the Computer has had a
chance to test your answer for RED or BLUE.

HINT: The lines must come BEFORE the Computer makes
your screen RED.

Did you figure out where the two lines should go in the program? They must
come after line 40 and before line 100:

50 PRINT “YOU MUST TYPE EITHER RED OR BLUE”
60 GOTO 20
See if you can make one more change to the program:

Instead of having the Computer end the program after it makes the screen red
or blue, have it go back and ask you to type RED or BLUE again.

 

HINT: You will need to change line 110 and add line 210.

Have you got a program written? Look on the next page for a diagram of ours.

57
58

 

10 PRINT “DO YOU WANT THE SCREEN RED OR BLUE?”
20 INPUT C$ (Ss
aoe

30 IF C$ = “RED” THEN 100
3 40 IF C$ = “BLUE” THEN 200 S t
: 3 50 PRINT “YOU MUST TYPE EITHER RED OR BLUE” 8

Xe x 460 GOTO 20
-

100 CLS(4) <
110 GOTO 10

200 CLS(3) < S
210 GOTO 10

 

 

 

 

To trace the path the Computer takes down this program, simply go down, from
one line to the next, following the arrows when told to. Notice the difference
between the arrows going from the IF/THEN and the GOTO lines:

gd SES ARBENE RNR R NERS

RULES ON IF/THEN AND GOTO

Baa a

(C$ = “RED” or C$ = “BLUE?”) is true.

GOTO is unconditional.
You follow these arrows whenever

you arrive at a GOTO line. \

AAXNARAARARRRARAAAARS

Although this chapter was short, you’ve learned one of the most important
programming concepts. We will be getting the Computer to make decisions all
through the rest of this book.

é IF/THEN is conditional.
é You only follow these arrows if the condition
 

 

 

 

IF/THEN
END

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


===== CHAPTER 7 =====

 

GAMES OF CHANCE

 

 
i

GAMES OF CHANCE

Thanks to a BASIC word called RND, your Computer can play almost any kind
of game involving chance or luck. Even if you don’t plan to play games with
your Computer, you’ll want to know how to use RND and PRINT @ — the
words we’re introducing in this Chapter. We'll also show you some more uses
for IF/THEN.

Type this:
10 PRINT RND(10)

RUN it. The Computer just picked a random number from 1 to 10. RUN it some
more times...

It’s as if the Computer is drawing a number from 1 to 10 out of a hat. The
number the Computer picks is unpredictable. Type and RUN this program.
Press (BREAK) when you satisfy yourself that the Computer is printing random
numbers:

   
 
 

10 PRINT RND(10);
20 GOTO 10

To have the Computer pick random numbers from 1 to 100, change line 10 to
this:

10 PRINT RND(100); 61
62

 

and RUN. How would you change this program to have the Computer pick a
random number from 1 to 255?

6 ie) 6 6 6) 8) @ 6 1% (0 m6 6, Hl 6S 16S 1; 1S! 6S [e fe. Ol Sie -e ] (OO © W! SONS IS 6 0! we & 6 le 16'S WO ©) Si 6 [e) 5S; SO) WE [0 'O: 0: 6! 6 & 2 eo le 16, 6 16 ©). 6 O'S le 1S © 6 WG: a 8 i 56 Oe

The answer is:

10 PRINT RND(255);

A COMPLETELY RANDOM SHOW

Just for the fun of it, let’s have the Computer compose a song made up of
random tones. Type this:

10 T = RND(255)
20 SOUND T, 1
30 GOTO 10

RUN it. Great music, eh? Press (BREAK) when you’ve heard enough.

To add a random visual presentation to this program, add a couple of lines to
make the Computer show a random color (1-8) just before it sounds each
random tone.

 
 

Here’s our program:

A, RND(255)
14 ¢C RND(8)
16 CLS(C)

20 SOUND T, 1
30 GOTO 10

We'll show you a couple of simple games in this Chapter. Feel free to use your
imagination to add interest to them — or invent your own games.

RUSSIAN ROULETTE

In our “Russian Roulette” game, the gun has 10 chambers. The Computer
picks, at random, which of the 10 chambers will have the fatal bullet. Type:

10 PRINT “CHOOSE YOUR CHAMBER(1-10)”
20 INPUT X

30 IF X = RND(10) THEN 100

40 SOUND 200, 1

50 PRINT “--CLICK--”’

60 GOTO 10

100 PRINT “BANG — YOU'RE DEAD”

First, in line 20, the player INPUTs X — a number from 1 to 10. Then the
Computer compares X with RND(10) — a random number from 1 to 10.

Now look at the arrows we drew:

IF X is equal to RND(10), THEN the Computer goes down to 100.

IF X is not equal to RND(10), THEN the Computer “clicks” and goes back up to
line 10 where you get another chance. . .

Let’s make the dead routine in line 100 better. Type:

 

63
 

 

100 FOR T = 133 TO 1 STEP -5

110 PRINT “ BANG!!!I!”"

120 SOUND T, 1

130 NEXT T

140 CLS

150 PRINT @ 230, “SORRY, YOU’RE DEAD”
160 SOUND 1, 50

170 PRINT @ 390, “NEXT VICTIM, PLEASE”

RUN the program. Here’s what happens in this program:
Lines 100 through 130 makes the Computer produce a sound of descending

Line 140 CLears the Screen. Since we did not choose a color number code, the
Computer assumes we want the screen green.

Look at lines 150 and 170. Both of these lines use PRINT @. Here’s the way
PRINT @ works:

Notice the grid we have below, showing each of the 511 positions on your video
screen. When writing the program, we wrote the two messages “SORRY,
YOU’RE DEAD” and “NEXT VICTIM PLEASE” on this grid, positioning
them where we wanted them on the screen.

SORRY, YOU’RE DEAD begins at location 230 (224 + 6). NEXT VICTIM
PLEASE begins at location 390 (384 + 6). Using these numbers in the PRINT
@ line, simply tells the Computer where we want the message printed.
 

 

011123 )4 [516171 {8 PTT TTT tt ms  “
t
aa | | | 1 | Lt
} | TE
|

Prt

|
+
|

  
      

aa | | | SORRY, YOU'RE DEAD | |

 

CL Ie ielelr| ef CPbensel TTT

4
++ +
| | |

  

 

 

Cc aa Ee eee ee BEE 4

 

Change this program, so that if the player DOES manage to stay alive for 10

clicks, the Computer pronounces the player the winner, printing this message \
on the screen:

 

f (01/2 3 4/516 | 7/8) 9110111213141516171819202122232425262728293031 \
1] | | | | | ] j | |

  

256 | HH Wott I WAGED HEHE
288 TO STAY Pelriviel TTT | Be

Hh \

 

 

le st eT)

65
 

 

HINT: You can use the FOR/NEXT loop, so that the Computer can keep count of the
number of clicks.

Our answer is to this is in the book.

ROLLING THE DICE

ee

>
N

’

For our next game, we'll first have to teach the Computer to roll the dice. To do
this, the Computer must roll two dice; that is, it must come up with two random
' numbers. Type:

/ 10 CLS

20 X = RND()

30 Y = RND()

40 R=X+Y

50 PRINT @ 200, X

60 PRINT @ 214, Y

70 PRINT @ 394, “YOU ROLLED A” R

80 PRINT @ 454, “DO YOU WANT ANOTHER ROLL?”
90 INPUT A$

100 IF A$ = “YES” THEN 10 |

 

“Loser!”

Aw = "Yes"
 

RUN the program. Let’s look at it:
Line 10 tells the Computer to CLear the Screen.

Line 20 has the Computer pick a random number from 1 to 6 for one of the die.
Line 30 has the Computer pick a random number for the other die.

Line 40 simply adds the two dice to get the total roll.
Lines 50-70 PRINT the results of the roll on the screen.

In line 90, you are able to INPUT whether you want the program to RUN
again. IF you type YES, the Computer goes back to line 10 and runs the
program again. Otherwise, since this is the last line in the program, the
program ends.

CRAPS

Now that you know how to get the Computer to roll the dice, it should be fairly
easy for you to write a Craps program. These are the rules of the game (in its
simplest form):

1. The player rolls the two dice. If he rolls a sum of 2 (“snake eyes”), a 3
(“cock-eyes”), or a 12 (“boxcars”) on the first roll, the player loses and the
game is over.

2. Ifthe player rolls a 7 or 11 on the first throw, (“a natural”), the player wins
and the game is over.

3. Ifany other number is rolled on the first roll, it becomes the player’s “point”.
He must keep rolling until he either “makes his point” by getting the same
number again to win, or rolls a 7, and loses.

You already know more than enough to write this program. Do it. Make the
Computer print it in an attractive format on your screen and keep the player
informed on what is happening. It may take you awhile to finish, but give it
your best. Good luck!

pr
‘ SS.

“Winner!”

67
 

 

Our answer to this is in the back.

RND
PRINT @

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


===== CHAPTER 8 =====

    
   

{

 
  

10 T= RND (255)
20 Sovowhs T, |

  
   

lo Peiwr " ——
20 INPoT AS Ol - GG

SAVE IT ON TAPE

 

 
SAVE IT ON TAPE

You'll soon be writing longer and more powerful programs. Perhaps you
already are. It certainly cramps your style to have the program disappear
everytime you turn the Computer off!

You can “save” (make a copy of) any of your programs on cassette tape. Once
the program’s on tape, you'll be able te “load” the program back into your
Computer’s memory anytime you want. We recommend that you use Radio
Shack’s CTR-80A cassette recorder (catalog number 26-1206) along with Radio
Shack’s Computer Tapes (catalog number 26-301).

This chapter is only for those of you that have this type of cassette recorder and
want to use it. If you don’t, you'll probably want to skip this chapter for now,
remembering that the information’s here whenever you need it.

Once you're used to it, you’ll find cassette tape easy to use. Simply follow these
steps:

A. Connect the Tape Recorder

1. Locate the CTR-80A Cassette Recorder, Interconnecting Cable and Radio
Shack Computer Recording Tape cassette.

2. Connect the short cable between the TAPE jack on the back of the TRS-80
and your Cassette Tape Recorder

 

71
72

 

You may substitute any name for
NAME.

e The small grey plug goes into the REM jack on the Recorder.

e@ The large grey plug goes into the AUX jack.
@ The black plug goes into the EAR jack.

3. Plug the Recorder into the wall outlet

B. Save a Program

1. Type any program into your Computer. RUN it to make sure it works.

2. Load the cassette tape, positioning it to the beginning of the tape. Press the
PLAY and RECORD buttons at the same time until they lock.

3. Name the program you want to SAVE. You may use any name with 8 or
fewer letters. For our example, we’ll use “NAME”.

4. SAVE on tape by typing this command:

CSAVE “NAME”

The motor on the Recorder will start and you'll be recording the Computer’s
program on tape. Watch the screen. When:

OK

returns and the motor stops, your program is recorded on tape. It is also still in
the Computer’s memory. It has only been copied.

LOADING

Reversing the process and loading (copying) the program from tape into the
Computer is just as easy:

1. Be sure the tape is fully rewound and the plugs are all in place.
 

2. Push the PLAY button down until it locks. Set the Volume Control to your
CTR-80A’s “Recommended Volume Level”. Your CTR-80A Manual gives
this recommended volume.

3. Type NEW to clear out any existing program.
4. Type the CLOAD command with the name of your program. For example:

CLOAD “NAME”

The Tape Recorder’s motor will start. Watch your screen. The letter:

Ss

    
 
 
 
 

will appear at the top left hand corner. This means the Computer is
Searching for your program. When the Computer has Found your program,
it will print the letter F and the name of your program. For example, if your
program name is NAME:

F NAME
will appear at the top of your screen. When the Computer prints:

OK

and the recorder motor stops, the program is “loaded” in memory. You may
now RUN the program.

SAVING MORE THAN ONE PROGRAM

To SAVE more than one program on the same tape, you must make sure you
are not recording on top of another program. This is an easy way to position the
tape to the end of your last program:

1. Rewind the tape to the beginning.
2. Press the PLAY button until it locks

73
74

 

_ You may replace the name X with any
name you know is NOT on the tape.

3. Type SKIPF and the name of the last program on your tape. For example, if
your last program is named “NAME”, type:

SKIPF “NAME”

The Computer will notify you when if Finds your program called NAME.
When it reaches the end of NAME, the recorder’s motor will stop and:

OK

will appear on your screen.

4. Once you've positioned the tape to the end of the last program, press the
RECORD and PLAY buttons, name your program, and CSAVE it.

If you can’t remember the name of your last program, type:

SKIPF “X”’

and watch the screen. The Computer will give you the name of each program it
encounters on the tape. It will print an I/O ERROR when it reaches the end of
the tape, but don’t worry about it. You’ve found what you were looking for —
the name of the last program on the tape.

Now you can type the SKIPF command with the name of this last program.
(Don’t forget to rewind the tape first).

TIPS ON MAKING GOOD RECORDINGS

Here are some tips for making good recordings:

@ When you're not using the Recorder for saving or loading, do not leave the
RECORD or PLAY keys down. Press STOP.

© Don’t attempt to re-record on a pre-recorded Computer tape. Even though
the recording process erases the old recording, just enough information may
 

be left to confuse the new recording. If you want to use the same tape a
second or third time, use a high-quality bulk tape eraser to be sure you erase

everything.

e If you want to save a taped program permanently, break off the Erase
Protect tab on the Cassette (see Tape Recorder’s Manual). When the tab(s)
has been broken off, you can’t press the RECORD key on your Recorder. This

will keep you from accidentally erasing that tape.

Now type as long of programs as you want, knowing you can make a permanent
copy of them on tape. Happy recording!

 

75

===== CHAPTER 9 =====

 

\
COLOR THE SCREEN

 

 
COLOR THE SCREEN

You've learned enough now to really start using the colors. Since color graphics
ideas usually come very quickly to people — and the good graphics programs
usually end up long — this Chapter just shows you how to get started. While going
through this Chapter, you'll probably want to stop from time to time and add on to
our programs or build your own. We hope you do. That’s a fast way to learn.

To get started, type:
10 CLS(0)

to make the screen black. Add these two lines and RUN the program: Be sure to type line 30. We'll explain
why later.

20 SET(0,0,3)
30 GOTO 30

Do you see the blue dot? It’s at the top left-hand corner of your screen. To put
the dot at the bottom right-hand corner, change line 20 and RUN the program:

20 SET(63,31,3)

Want to put it in the middle of the screen? RUN the program using this for line
20:

77
 

78

 

20 SET(31,14,3)

SET tells the Computer to SET a dot on your screen at a certain horizontal and
vertical location.

e@ The first number you type is the horizontal location. This may be a number
from 0 to 63.

@ The second number is the vertical location. It may be a number between 0
and 31.

In the Appendix, there’s a grid on your screen, “Graphics Screen Locations”.
The grid divides your screen into the 64 (0 to 63) horizontal locations and 32 (0
to 31) vertical locations. Use this grid in planning your graphics illustrations.

All of this explains what the first two numbers are for, but what about 3, the
third number? Try using some numbers other than 3 for the third number.
Type each of these lines and RUN the program:

20 SET(31,14,4)
20 SET(31,14,1)

Got it figured out? With number 4, you get a red dot, and with number 1 you get
a green dot. The number codes are the same as the CLS number codes — 0 to 8.
These are listed in your Appendix, “BASIC Colors”.

Now, what’s the GOTO line for? Try deleting the GOTO line from your
program and RUN it:

10 CLS(0)
20 SET(31,14,1)

It looks like no dot was SET this time. Actually the dot was SET, but when the
program ended, the Computer printed its OK message on top of the dot.

To avoid this, type the GOTO line at the end of the program. It sets up an
infinite loop (going to itself over and over again) so that the program will never end.
 

SETTING TWO DOTS

To SET more than one dot, you need to do a little planning. Erase your program
and RUN this program:

10 CLS(0)

20 SET(32,14,3)
30 SET(33,14,3)
40 GOTO 40

You should now have two blue dots—side by side—in the middle of your
screen.

Now change the color of the right dot so you'll have one blue and one red dot.
Type:
30 SET(33,14,4)

and RUN the program. . . Both dots are red.

Look again at the “Graphics Screen Locations” grid in your Appendix.
Notice the darker lines group the dots together into blocks of four. For
instance, the block in the middle of the grid contains these 4 dots:

Horizontal Vertical
Location 32 14
Location 33 14
Location 32 15
Location 33 15

Each dot within the block must either be:

1. the same color (colors 1-8)
or

2. black

In our program, we tried to get the Computer to SET two dots with different
colors — blue and red — within the same block. Since the Computer can’t do
that, it SETs both dots the second color — red.

Type this and RUN the program:

(/

\)

“Set Dot!”

79
80

 

 

 

 

“Funny Face!”

30 SET(34,14,4)

Since the dot in location 34, 14 is in a different block, the Computer can SET
the two dots in different colors.

THE COMPUTER’S FACE

With this groundwork, you can draw whatever you want. We'll draw a simple
picture of a Computer. First draw the top and the bottom of the head. We'll
make it buff. Type:

5 CLS(0)

10
20
30
40
50

and RUN.

FOR H = 15 TO 48
SET (H,5,5)

SET (H,20,5)
NEXT H

GOTO 50

This is what you should have on your screen. (The lines should be buff rather
than white, like we have them):

 
 

Notice we’ve changed line 50 — the
GOTO line.

/

Lines 10 and 40 set up a FOR/NEXT loop for H — making the horizontal
locations 15 through 48 for the top and the bottom lines.

Line 20 SETs the top line. The horizontal location is 15 through 48 and the
vertical location is 5.

Line 30 SETs the bottom line. The horizontal location, again, is 15 through 48
and the vertical location is 20.

To SET the left and right sides of the head type these lines:

50 FOR V = 57020
60 SET(15,V,5)

70 SET(48,V,5)

80 NEXT V

90 GOTO 90

and RUN.

We'll make the nose orange. Type:
90 SET(32,13,8)

and the mouth red. Type:
100 FOR H = 28 TO 36
110 SET(H,16,4)
120 NEXT H

and blue eyes. Type:
130 SET(25,10,3)

140 SET(38,10,3)
150 GOTO 150

RUN the program. This is what your screen should look like now:

81
82

 

You don’t need to tell the Computer

the color of the dot to RESET (erase)
it.

 

A BLINKING COMPUTER

By adding a couple of lines, we can make the Computer blink. Type:
150 RESET(38,10)

and RUN the program. What you should have on your screen now is the same
face as above, except the right eye is missing. RESET tells the Computer to

erase the dot in the horizontal location 38 and the vertical location 10. That’s
the right eye.

To make it blink, we’ll simply SET and RESET th

e right eye over and over
again, by adding line 160:

aA &
Ore

160 GOTO 140
 

LIST your program to see if it still looks like mine:

5 CLS(0)

10
20
30
40

50
60
70
80

90

100
110
120

130
140
150
160

and: RUN it...

FOR H = 15 T0 48
SET(H,5,5)
SET(H,20,5)

NEMe Ho. eet pe ss bs fe

FOR V = 5 T0 20
SET(15,V,5)
SET(48,V,5)
NEXT V

SET(32,13,8)
FOR H = 28 TO 36

SET(H,16,4) —————. 70 TH

NEXT H

SET(25,10,3)
SET(38,10,3)

RESET(38,10)
GOTO 140

Snowe

—_—_£qeu

Try your hand at some pictures. I’m sure you have better

artistic skills than we do.

THE BOUNCING DOT

By using SET and RESET, we can make a moving picture. Type and RUN
these lines to make the dot go down:

5 CLS(0)

10 FORV =0T031
_20 SET(31,V,3)

30 RESETGL1,V)

40 NEXT V

 
84

 

 

Every dot that is SET on line 20 is RESET (erased) on line 30. Add these lines to
make the dot go back up:

50 FOR V = 31700 STEP -1
60 SET(31,V,3)

70 RESET(31,V)

80 NEXT V

and this line to make the dot go up and down, over and over again:
90 GOTO 10

and RUN it. To slow the dot down — it will look a little better — change lines 30
and 70:

30 IF V > 0 THEN RESET(31,V-1)
70 IF V < 31 THEN RESET(31,V +1)

The > sign means the same as it does in math — greater than. The < sign
means less than.

SET and RESET opens up all sorts of possibilities — moving targets, animated
pictures, etc. Use your imagination in experimenting with this combination.

IF YOU HAVE THE JOYSTICKS...

If you have joysticks with your Computer, you have many more options open to
you. If you haven’t connected them yet, do it. Simply plug them in to the back of
your Computer. They only fit in the correct slot, so don’t worry about connect-
ing them to the wrong one.

Now, type this short program which demonstrates how they work:
 

10
20
30
40
50
60

CLS

PRINT @ 0, JOYSTK(0);
PRINT @ 5, JOYSTK(1);
PRINT @ 10, JOYSTK(2);
PRINT @ 15, JOYSTK(3);
GOTO 20

RUN the program. See the four numbers on your screen. These numbers tell
the Computer the horizontal and vertical coordinates of your two joysticks’
“floating switches”.

Now to see what each of the four numbers are referring to. Grab the “floating
switch” of one of your joysticks. Keeping it in the center, move it from left to
right. Either the first number or the third number of your screen will change,
going through all the numbers from 0 to 63. Move the “floating switch of your
other joystick from left to right.

Place the joystick that makes the first number change on the left side.

Move the floating switches up and down, keeping them in the center. Moving
the left joystick up and down makes the second number change from 0 to 63.
Moving the right joystick up and down makes the fourth number change from 0

to 63.

This is how the Computer reads the position of your joysticks:

LEFT JOYSTICK
0
0 63
63
JOYSTK(O) JOYSTK(1)

RIGHT JOYSTICK

— JOYSTK(2)

63

JOYSTK(3)

‘Be sure to type the semicolons at the
ends of lines 20, 30, 40, and 50.

The second or fourth number might
change also, but NOT from 0 to 63.

85
86

 

 

JOYSTK(0) and JOYSTK(1) tell the Computer the read the position of your left
joystick:

e JOYSTK(0) makes it read the horizontal (left to right) coordinate.
e@ JOYSTK(1) makes it read the vertical (up and down) coordinate.

JOYSTK(2) and JOYSTK(3) tell the Computer to read the position of your
right joystick:

@ JOYSTK(2) makes it read the horizontal coordinate.

@e JOYSTK(3) makes it read the vertical coordinate.

One more thing. Delete line 50 and RUN the program. It works almost the
same, doesn’t it, except it doesn’t read JOYSTK(3) — the vertical position of
your right joystick.

Now delete line 20 and change line 60:
60 GOTO 30

RUN the program. Move all the switches around. This time it doesn’t work at
all. The Computer will not read any of the coordinates unless you first have it
read JOYSTK(0). Type these lines:

20 A = JOYSTK(O)
60 GOTO 20

and RUN the program. Even though the Computer is not printing the location
of JOYSTK(0), it is still reading it. Everything else works like it’s supposed to.
Remember that anytime you're having the Computer read to coordinates of
JOYSTK(1), JOYSTK(2), or JOYSTK(3), you must first have it read
JOYSTK(0).
 

MAKE PAINT BRUSHES OUT OF JOYSTICKS:

Type this:

10 CLS(0)

20 H = JOYSTK(O)

30 V = JOYSTK(1)

AQ JE M3), THEN Vi = V8 32

80 SET(H,V,3)
90 GOTO 20

RUN it... Use the revolving switch of your left joystick to paint a picture.
(Move the switch slowly so that the Computer has time to read its coordinates).

Line 20 reads H — the horizontal position of your left joystick. This could be a
number from 0 to 63.

Line 30 reads V — its vertical position. This also could be a number from 0 to
63. Since the highest vertical position on your screen is 31, we had to add line
40 to the program. Line 40 makes V always equal to a number from 0 to 31.

Line 80 SETs a blue dot at H and V.

Line 90 goes back to get the next horizontal and vertical positions of your joysticks.

We haven’t even used the right joystick. Perhaps we could use it for color. Add
these lines:

50 C = JOYSTK(2)

60 IF C < 31 THENC = 3

70 IF C > = 31 THEN C = 4
80 SET(H,V,C)

RUN the program. Move your right joystick to the right and the Computer
makes C = 3. It SETs red dots. Move it to the left and the Computer makes C =
4 and SETs blue dots.

Want to make the buttons on your joysticks do something? Add these lines to
the end of your program:

>= means greater than or equal to

 

87
88

 

If you press the buttons when you're
not RUNning the program you will
get @ABCDEFG or HIJKLMNO.

100 P = PEEK(65280)
110 PRINT P
120 GOTO 100

Now type:
RUN 100

This tells the Computer to only RUN lines 100 through the end of the program.
Your computer should be printing either 255 or 127 over and over again.

PEEK tells the Computer to look at a certain spot in its memory to see what
number’s there. We had it look at the number in location 65280. As long as
youre not pressing either of the buttons, this spot contains the number 255 or
127.

Press the left button. When you press it, this memory location contains either
the number 126 or 254.

Press the right button. This makes this memory location contain either the
number 125 or 253.

Using this information, you can make the computer do whatever you want
when you press one of the buttons. We'll make it go back to line 10 and CLS(0)
—clear the screen to black — when you press the left button. Change lines 110
and 120:

110 IFP
120 IF P

126 THEN 10
254 THEN 10

Delete line 90 and add this line:

130 GOTO 20

RUN the program. Start your paintings. Press the left button when you want

to clear the screen and start over again.
‘
 

SET
RESET
JOYSTK
PEEK

 

NOTES:

 

 

 

 

 

 

 

 

 

 

89

===== CHAPTER 10 =====

SS
ONE FANTASTIC TEACHER

 
e
epecece
a
'e
e'
“canes

e
A

ONE FANTASTIC TEACHER

Your Computer has all the attributes of a natural born teacher. After all, it’s
patient, tireless, and detail conscious (. . . perhapsa bit nit-picky . . .). Depend-
ing on the programmer — we’re talking about you, of course — it can be
imaginative, consoling, and quite enthusiastic.

So lets get on with it! We can use RND to get the Computer to drill us on one
math problem after the next. Type:

> 10 CLS
| 20 X = RND(15)
30 Y = RND(15)
40 PRINT “WHAT IS” X “*” Y
45 INPUT A

50 IF A = X * Y THEN 90
60 PRINT “THE ANSWER IS” X*Y
70 PRINT “BETTER LUCK NEXT TIME”
80 GOTO 100
> 90 PRINT “CORRECT!!!”

: > 100 PRINT “PRESS <ENTER> WHEN READY FOR ANOTHER”
105 INPUT A$ :
110 GOTO 10

 

 

91
ay)

 

This program will drill you on your multiplication tables, from 1 to 15, and
check your answers.

How would you change this program to get the Computer to drill you on

addition problems from 1 to 100:

 

Here’s the lines we changed:

20
30
40
45
50
60

X RND(100)

¥ RND(100)

PRINT “WHAT IS” X “+” Y
INPUT A

IF A = X + Y THEN 90

PRINT “THE ANSWER IS” X + Y

To make the program a little more interesting we can have the Computer keep
a running total of all the correct answers. Type:

15-7 = T Has
9 C=C +1
98 PRINT “THAT IS” C “OUT OF” T “CORRECT ANSWERS”

T keeps a count of all the questions the Computer asks you. When you first
 

RUN the program T equals zero. Then, everytime the Computer gets to line 15,
it adds 1 to T.

C does just about the same thing. It keeps a count of the number of correct

answers. Since it is on line 95, the Computer will not increase C unless you get _ When you first turn on the Computer,

   

i _ all numeric variables equal 0. Also, —

a correct answer. when you type NEW CENTER), all
_ numeric variables equal0.

There are many ways to make this program more entertaining. Add some lines = aoa

to the program which will get the Computer to do one or more of the following:

1. Call you by name

2. Reward your correct answer with a sound and light show

3. Print the problem and messages attractively on your screen. (Use PRINT @ veges Tia Ree

for this). _ There are many variations you could —

_ try with this prograr

4. Keep a running total of the percent of correct answers. _ the Computer could

5. End the program if you get 10 answers in a row correct. is wee eee

 

Use your imagination on this one. We have a program in back which does all
five of the above.

 
94

 

 

FIRST BUILD YOUR COMPUTER’S VOCABULARY...

To build your Computer’s vocabulary (so that it can build yours!) type and
RUN this program:

10 DATA APPLES, ORANGES, PEARS
20 FOR X = 1 TO 3

30 READ F$

40 NEXT X

So what happened? Nothing? Nothing that you can see, that is. To see what the
Computer is doing, add this line and RUN it:

35 PRINT “FS = :” F$

Line 30 tells the Computer to:

1. Look for a DATA line
2. READ the first item in the list — APPLES
3. Give APPLES an F$ label

4. “Cross out” APPLES

The second time the Computer gets to line 30 it is told to do the same things:

1. Look for a DATA line

2. READ the first item — this time it is ORANGES
3. Give ORANGES the F$ label

4. “Cross out” ORANGES

This is what is happening in your Computer’s memory when you RUN the
program:

  
  

 
 

YOUR COMPUTER’S MEMORY

oe FS emp APPLES
ya

     

ORANGES
PEJKRS
 

What if you want the Computer to READ the same list over again? It’s already
crossed everything out ... Type:

60 GOTO 10

and RUN the program. It prints 70D ERROR IN 30. OD means Out of Data.
The Computer has already crossed out its Data.

Type this line and RUN the program:
50 RESTORE

Now it’s as if the Computer never crossed anything out. The Computer will
READ the list over and over again.

The nice thing about DATA lines is that you can put them anywhere you want
in the program. RUN each of these programs:

10 DATA APPLES 10 DATA APPLES, ORANGES
20 DATA ORANGES 20 DATA PEARS

30 FORX =1T03 30 FORX =1T03

40 READ F$ 40 READ F$

50 PRINT “F$ = :” F$ 50 PRINT “F$ = :” F$

60 NEXT X 60 NEXT X

70 DATA PEARS

Remember how to make the Computer
pause while RUNning a program?
Press (SHIFT) © Press any key to get it
to continue.

 

30 FORX =1T03 30 FORX = 1T03

40 READ F$ 40 READ F$

50 PRINT “F$ = :” F$ 50 PRINT “FS = :” F$

60 NEXT X 60 NEXT X

70 DATA APPLES 70 DATAAPPLES, ORANGES, PEARS

80 DATA ORANGES
90 DATA PEARS

 

95
 

96

 

“Cataclysmic!”

They all work the same, don’t they? This knowledge should be handy for
something...

..NOW HAVE IT BUILD YOUR VOCABULARY

Here’s some words and definitions you might want to be tested on:

Words Definitions

10 DATA TACITURN, HABITUALLY UNTALKATIVE
20 DATA LOQUACIOUS, VERY TALKATIVE

30 DATA VOCIFEROUS, LOUD AND VEHEMENT

40 DATA TERSE, CONCISE

50 DATA EFFUSIVE, DEMONSTRATIVE OR GUSHY

Now to get the Computer to pick out a word at random from the list. Hmmm... .
there are ten items in the list. Maybe this will work:

60 N = RND(10)
70 FORX=1TON
(% READ A$
90 NEXT X
100 PRINT “THE RANDOM WORD IS :” A$

RUN it a couple of times to see if it works.

It doesn’t quite work like we want it to. The Computer is just as likely to stop at
a definition as a word. What we really want the Computer to do is to pick a
random word from items 1, 3, 5, 7, or 9.

Fortunately, there is a word which will explain this to the Computer. Type:
65 IF INT(N/2) = N/2 THENN=N-—1

RUN the program a few times. It should work now.

INT tells the Computer to only look at the whole portion of the number and
 

ignore the decimal part. For instance, the Computer sees INT(3.9) as 3.

Here’s how line 65 works. Say the random number the Computer picks is 10.
The Computer does this calculation:

INT(10/2) = 10/2
INT(5) = 5
5=5

Since this is true, 5 does equal 5, the Computer completes the THEN portion of
the line and makes N equal to 9 (10 — 1).

However, if the Computer picks 9, it does this:

INT(9/2) = 9/2
INT(4.5) = 4.5
= 45

Since this is not true, 4 does not equal 4.5, the Computer doesn’t subtract 1 from
N. 9 remains 9.

Now that the Computer is able to READ a random word, it must also READ the
word’s definition. You can do this simply by adding these lines to the end of the
program:

110 READ B$
120 PRINT “THE DEFINITION IS :” BS

RUN it several times now. To get the Computer to print one random word and
definition after the next, add this line to the beginning of the program:

5 CLEAR 100

to give the Computer plenty of string space. And add these lines to the end of
the program:

130 RESTORE
140 GOTO 60

So that the Computer can pick out a new random word and its definition froma

Oi;
 

clean slate of data items.

Here is the way the entire program looks now:
5 CLEAR

10 DATA TACITURN, HABITUALLY UNTALKATIVE
20 DATA LOQUACIOUS, VERY TALKATIVE

30 DATA VOCIFEROUS, LOUD AND VEHEMENT

40 DATA TERSE, CONCISE

50 DATA EFFUSIVE, DEMONSTRATIVE OR GUSHY

60 N = RND(10)
65 IF INT(N/2) = N/2 THENN=N-—-1
70 FORX =1TON
C 80 READ A$
90 NEXT X
100 PRINT “A RANDOM WORD IS :” A$
110 READ B$
120 PRINT “ITS DEFINITION IS :” BS

130 RESTORE
140 GOTO 60

Want to complete this program? Try it before turning the page to see ours.
Program it so that the Computer will:

PRINT the definition ONLY

 

i
2. Ask you for the word

3. Compare the word with the correct random word
4,

Tell you if your answer is correct. If your answer is incorrect, have it
PRINT the correct word.

HEHE aE ESA ASCH HCPA EES HICH HS CIECH HIC HACC COE a ARCH 2 2 2A 2K HACK OK ooh a a aK a a a aaa CHIC HACC a aE aaa ak a ARCHIE a aK a aR AICS Ke ae ae ake ak ke ae ease ae ae skeoke ate ok

98
 

Here’s our program:

5
10
20
30
40
50
60
65
70
80
90

110
120
130
140
ro koe
160
170
180
190
200

 

CLEAR 500
DATA TACITURN, HABITUALLY UNTALKATIVE
DATA LOQUACIOUS, VERY TALKATIVE
DATA VOCIFEROUS, LOUD AND VEHEMENT
DATA TERSE, CONCISE
DATA EFFUSIVE, DEMONSTRATIVE OR GUSHY
N = RND(10)
IF INT(N/2) = N/2 THENN=N-—1
FORX = 1TON |

READ A$
NEXT X
READ B$
PRINT “WHAT WORD MEANS :” B$
RESTORE
INPUT R$
IF R$ = A$ THEN 190
PRINT “WRONG”
PRINT “THE CORRECT WORD IS :” A$
GOTO 60
PRINT “CORRECT”
GOTO 60

 

Feel free to dress the program up with —

_a good looking screen format, sound, —

99
 

DATA
READ
RESTORE
INT
CLEAR

 

100
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

101

===== CHAPTER 11 =====

 AX {BY +: ©) =.D'+ E(G/W) =F

 

 
veeooes
a

HELP WITH MATH

Solving complicated math formulas with super speed and precision is an area
where your Computer shines. But before driving yourself crazy typing a bunch
of math formulas, there are some shortcuts and hints you'll probably want to
know about.

One easy way to handle complicated math formulas is by using SUBROU-
TINES. Type and RUN this program:

10 PRINT “EXECUTING THE MAIN PROGRAM”
20 GOSUB 500

30 PRINT “NOW BACK IN THE MAIN PROGRAM”
40 END

500 PRINT “EXECUTING THE SUBROUTINE”
510 RETURN

Line 20 tells the Computer to GO to the SUBroutine beginning at line 500.
RETURN tells the Computer to return back to the BASIC word immediately
following GOSUB.

Delete line 40 and see what happens when you RUN the program.

Did you delete it?

103
 

See something different about
INPUT? We can have the Computer
PRINT a message before waiting for
us to INPUT something.

104

If you did, this is what’s on your screen:

EXECUTING THE MAIN PROGRAM
EXECUTING THE SUBROUTINE
NOW BACK IN THE MAIN PROGRAM
EXECUTING THE SUBROUTINE

?RG ERROR IN 510

RG means RETURN without GOSUB. Can you see why deleting END in line
40 would cause this error?

At first, the Computer went through the program just like it did before you
deleted the END line. It was sent to the subroutine in line 500 by GOSUB and
it returned to the BASIC word immediately following GOSUB.

Then, since you deleted END, it went to the next line in the program which was
the subroutine. When it got to RETURN, it did not know where to return to,
since this time it had not been sent to the subroutine by a GOSUB.

Here’s a subroutine which raises a number to any power you want:

10
20
ee oO
40
50

 

INPUT “TYPE A NUMBER”; N

INPUT “TYPE THE POWER YOU WANT IT RAISED TO”; P
GOSUB 2000

PRINT: PRINT N” TO THE” P’” POWERIS” E

GOTO 10

> 2000 REM FORMULA FOR RAISING A NUMBER TO A POWER
2010 E=1
2020 FORX =1TOP
2030 E=E*N
2040 NEXT X
2050 IF P = OTHENE =1
2060 RETURN

Notice we introduced a couple of new things in the program.

Look at line 40. If you find it easier, you can combine two or more program lines
into one, using a colon to separate the two lines. Line 40 contains the two lines:
 

PRINT
and
PRINT N” TO THE” P” POWERIS” E

Line 2000 has something else new — REM.

REM doesn’t mean anything to the Computer. The Computer ignores any line
beginning with REM. You can put REM lines anywhere you want in your
program, so that you can remember what the program does. These REM lines
will make no difference to the way the program works.

If you don’t believe us, add these lines and RUN the program to see if they
make any difference:

5 REM THIS IS A PECULIAR PROGRAM,
17 REM THIS LINE SHOULD MESS UP THE PROGRAM
45 REM THE NEXT LINE KEEPS THE SUBPROGRAM SEPARATED

Satisfied? ... Good.

Change the program so that the Computer prints a table of squares (a number
to the power of 2) for numbers, say, from 2 to 10.

  

é

The answer is in the back of the book.

en

_ PRINT by itself tells the Computer to

 

105
 

GIVE THE COMPUTER A LITTLE HELP

As math formulas get more complex, your Computer will need some help
understanding them. For example, what if you want the Computer to solve this

problem:
Divide the sum of 13 + 3 by 8
The word “operation” means some-
thing you’re getting the Computer to You might want the Computer to solve the problem like this:
do. Here, we’re talking about the
“operations” of adding, aL! 13 + 3/8 = 16/8 =2
multiplying, and dividing.

106

But your Computer solves it differently. Type this command line:

PRINT 13 + 3/8 (ENTER)

What the Computer did was logical according to its rules:

CoS eee ee

RULES ON ARITHMETIC

1. any multiplication and division operations are solved first

2. addition and subtraction operations are solved last

The Computer solves arithmetic problems in this order 0

aa aT,

\> in case of a tie (that is, more than one multiplication/division or addition/subtrac- 0
tion operation) the operations are performed from left to right ;

WAAAARAARAARAAAAAA
 

In the problem above the Computer followed its rules. It performed the division
operation first (3/8 = .375) and then the addition (13 + .875 = 13.375). To get

the Computer to solve the problem differently, you can use parenthesis. Type
this line:

PRINT (13 + 3)/8 (ENTER) ~ -

Whenever the Computer sees an operation in parenthesis, it solves that before
solving anything else.

What do you think the Computer will PRINT as the answers to each of these
problems:

 

Finished? Type each of the command lines to check your answers.

What if you want the Computer to solve this problem?
Divide 10 minus the difference of 5 minus 1 by 2

That is what you’re actually asking the Computer to do:
G0 = (5 — 1))'7-2

When the Computer sees a problem with more than one set of parenthesis, it

107
108

 

solves the inside parenthesis and then moves to the outside parenthesis. In
other words, it does this:

ao — BR) / 2

es 6/2=3

ANANRRARRARRARAAVLAY

RULES ON PARENTHESIS

1. When the Computer sees a problem containing parenthesis, it solves the
\ operation inside the parenthesis BEFORE solving the rest of the

operations.
2. If there are parenthesis inside parenthesis, the Computer solves the

innermost parenthesis first and works its way out. ¢

ARARARAAAAAAAAAAALA

AAA

Insert parenthesis in the problem below so that the Computer will PRINT 28 as
the answer: ‘

 
 

Answer:

PRINT 30° '(97— (8° = (7 —"6)))

IS SAVING WORTH IT?

With what you’ve learned in this chapter, you can let the Computer do all the
math by putting complicated math formulas in your subroutines. The program
below uses two subroutines. It’s for those of you who save by putting the same
amount of money in the bank each month:

10 INPUT “YOUR MONTHLY DEPOSIT”; D

20 INPUT “BANK'S ANNUAL INTEREST RATE”; I
30 I= 1/12* 01

40 INPUT “NUMBER OF DEPOSITS”; P

50 GOSUB 1000

 

 

PRINT “YOU WILL HAVE $” FV“ IN” P “ MONTHS”
END

REM COMPOUND MONTHLY INTEREST FORMULA
N=1+1]1

GOSUB 2000

FV = D* (E -— 1/1)

RETURN

REM FORMULA FOR RAISING A NUMBER TO A POWER
E=1

FOR X = 1T0OP

E=E*N

NEXT X

IF P= OTHENE = 1

RETURN

Notice that we have one subprogram “calling” another subroutine. This is
perfectly OK with the Computer as long as you have a GOSUB to send the
Computer to each subroutine, and a RETURN in each subroutine to return the

 

| |

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

“A PENNY SAVED...”

109
iio.

 

Computer to the BASIC word following each GOSUB.

If you will be using your Computer a lot to help with math or accounting, you
might want to save all your math formulas on tape as subroutines. Then, when

you are writing a program that uses one of them, simply load the subroutine
from tape — it’ll then be part of your program.

GOSUB
RETURN
REM

Cv) Order of operations

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ae


===== CHAPTER 12 =====

 

 

 

 

 

 

 

A GIFT WITH WORDS

 
on
me

A GIFT WITH WORDS

One of your Computer’s greatest skills is its gift with words. It can tirelessly
twist, combine, or separate words to anything you want. Because of this gift,
you can teach it to read, write, and even carry on a halfway decent conversa-
tion.

 

For starters, see what you think of this:

10 PRINT “TYPE A SENTENCE”

20 INPUT S$

30 PRINT “YOUR SENTENCE HAS ” LEN(S$) ‘\ CHARACTERS”
40 INPUT “WANT TO TRY ANOTHER”; A$

50 IF AS = “YES” THEN 10

Impressed? LEN(S$) tells the Computer to compute the LENgth of the string
S$— your sentence. Your obedient Computer counts every single character in
the sentence, including spaces and punctuation marks.

Here’s another skill it has. Erase your program and type this to make it
compose a poem (of sorts):

10, AS i=)>A. ROSE’

20 BS Say NS uy

30 C$ = “IS A ROSE”

40 DS = BS + C$

50 E$ = “AND SO FORTH AND SO ON”
60 FS = A$ + D$ + DS + BS + EG

70 PRINT F$ 113
114

 

Here the Computer combines strings. The plus sign tells it to do this. D$
combines B$ and C$ to get “IS A ROSE”, and you can see what strings are
combined to form F$.

A word of caution about combining strings — add this line to your program and
RUN it:

80 G$ = F$ + F$ + F$ + FS + FS + FS + FS

When you RUN this program, the Computer prints 70S ERROR IN 80. OS
means Out of String Space. The Computer only reserves about 50 characters
for working with strings. Add this line to the beginning of the program for
reserving plenty of string space:

5 CLEAR 500

RUN the program again. This takes care of the first problem, but there’s still
another.

This time the Computer prints 7LS ERROR IN 80. LS means string too long.
Line 80 asks the Computer to form a string — G$ — with more than 255
characters. Your Computer simply can’t manage to remember a string with
that many characters.

Now that the Computer has combined strings, let’s get it to take one apart.
Type and RUN this program:

10 INPUT “TYPE A WORD”; W$
20 PRINT “THE FIRST LETTER IS : ” LEFT$ (W$,1)

30 PRINT “THE LAST 2 LETTERS ARE : ” RIGHTS (W$,2)
40 GOTO 10

Here’s what your Computer is doing:

In line 10 you INPUT a string for W$. Let’s say the string is MACHINE:

COMPUTER MEMORY

W$ — > MACHINE

 
 

Your Computer then performs several calculations in lines 20 and 30 to get the
first LEFT letter and the last 2 RIGHT letters of the string:

  

LEFT$ (W$,1) RIGHT$ (W$,2)

Try RUNning the program a few times until you get the hang of it.
Add this line to the program:

5 CLEAR 500

So that your Computer will set aside plenty of space for working with strings.
Now INPUT a sentence rather than a word.

Pee She hae ete 8 SUPT Se AR ee eee. BBO eh Ore Ne a) Gps eie, eS he] me he MEN ab ame 6.6.0 ewan g letuieleve, eR p.e7 0 ile te) Sioce. eo ellene tele: sre lee ie lalelecoieneiw bce te

How would you change lines 20 and 30 so that the Computer will give you the
first 5 letters and the last 6 letters of your string?

 

Answers:

20 PRINT “THE FIRST FIVE LETTERS ARE :” LEFT$ (W$,5)
30 PRINT “THE LAST SIX LETTERS ARE :” RIGHT$ (W$,6)

PES IAT GS POO Se OR SB) 8 i658. OO Oe ee ee 6 8\'e (a8 eM) 80) 0 6h am A / eT Si. 6) 8) C0. ¥@ 16 ere) pole \al.e; (al eie\s V6 eF¥! &'@ opie lh ae 6.66026, 6 e18\ ep alee ple elie (e706 btere pile elenm

‘i oe
116

 

Remember how to erase a program?
Type:
NEW (ENTER

Erase your program and type this one:

10
20
30
40
50
60
70
80
90

CLEAR 500

INPUT “TYPE A SENTENCE”; S$

PRINT “TYPE A NUMBER FROM 1 TO ” LEN(S$)

INPUT X

PRINT “THE MIDSTRING WILL BEGIN WITH CHARACTER ” X
PRINT “TYPE A NUMBER FROM 1 TO ” LEN(S$) — X + 1

INPUT Y

PRINT “THE MIDSTRING WILL BE” Y “CHARACTERS LONG”
PRINT “THIS MIDSTRING IS :” MID$(S$,X,Y)

100 GOTO 20

RUN this program a few times to see if you can figure out how MID$ works.
Here’s how the program works. Say you INPUT “HERE IS A STRING” for your

sentence:

   
   
 

YOUR COMPUTER’S MEMORY
S$ ef» HERE IS A STRING

In line 30, the computer first calculates the LENgth of S$ — 16 characters. It
then asks you to choose a number from 1 to 16. Let’s say you pick the number 6.

The Computer then, in line 60, asks you to pick another number from 1 to 11
(16-6) plus 1. Say you pick the number 4.

 
   
  
   
 

YOUR COMPUTER’S MEMORY

Xe 6
Y——> 4

  
 

In line 90, the Computer gives you a MID string of S$ which begins at character
number 6 and is 4 characters long:

 

1 2 3 4 5 6 7 i Bi 10 26ll V2 ATS) AA SE EG
A MERRY CE bea Sat Lo Ne G
MID$(S$,6,4)

Here’s something else you can do with MID$. Erase your program and type:

10 INPUT “TYPE A SENTENCE”; S$

20 INPUT “TYPE A WORD IN THE SENTENCE”; W$
30 L = LEN(W$)

40 FOR X = 1 TO LEN(S$)

50 IF MID$(S$,X,L) = W$ THEN 90

60 NEXT X

70 PRINT “YOUR WORD ISN’T IN THE SENTENCE”
80 END

90 PRINT W$ “--BEGINS AT CHARACTER NO.” X

RUN this program a few times. Here’s how it works.

Say you type in the above sentence, and the word you INPUT for W$ is “IS”. In
line 30, the Computer then calculates the LENgth of W$ — 2 characters.

    
  

YOUR COMPUTER’S MEMORY

0 O S$ ==> HERE IS A STRING
WS -—=—3 IS

L a 2

 
     
 

The Computer then goes through the FOR/NEXT loop (lines 40-90) counting
each character in S$ beginning with character 1 and ending with character
number LEN(S$) — 16.

These types of programs can be used

to sort through large files of informa- —

tion. For instance, by separating
strings, you could look through a
mailing list for TEXAS addresses.

117
 

Every time it counts a new character, the Computer looks at a new MID string.
Each MID string begins at character X and is L or 2 characters long.

For example, when X equals 1, the Computer looks at this MID string:

Sak
SE
23>
MID$(S$,1,2)

  
  

Ri E I S A S fa leceR:s il

The fourth time through the loop, when X equals 4, the Computer looks at this:

  

MID$(S$,4,,2)

It finally finds the MID string it is looking for when X equals 6.

 

YOUR COMPUTER CAN BE A TOUGH EDITOR

 

 

“#@b/&$!”

Are you beginning to get a picture of the Computer hacking away at your
sentences with a red pen? You can program it to help refine your writing and
save you hours of typing and rewriting.

Say you had a phrase you want to add to:

10 A$ = “CHANGE A SENTENCE.”

Add to this one-line program so that the Computer will insert these words at
the beginning of the sentence:

IT’S EASY TO
and PRINT the new sentence:

IT’S EASY TO CHANGE A SENTENCE
118
 

 

This is our program:

10 A$ “CHANGE A SENTENCE.”
20 BS “IT'S: EASY TO”

30 C$ = BS ape NUE A$

40 PRINT C$

Now see if you can add to the program to get the Computer to:

1. Find the beginning location of the MID string:
A SENTENCE

2. Delete the words A SENTENCE, forming a new string:
IT’S EASY TO CHANGE

3. Add these words to the end of the new string:

ANYTHING YOU WANT

4. And PRINT the newly formed string:

IT’S EASY TO CHANGE ANYTHING YOU WANT

119
 

 

HINT: To form the string IT’S EASY TO CHANGE, you need to get the LEFT portion of
the string IT’S EASY TO CHANGE A SENTENCE.

CEs ine ewe: 6 wcare 0} wate, Siete.» le ele pues ib! %, His, bu 6 fale, shiek or/Ole: 6 allele 6 lo te: > Wie pe, Bre. e110 9) e)fei @: ois/ale 6 Stew) ejetie el S)roeWa eis) (overs) ae [ipirevenelfe: eee eye Fe S's (6: 81 8 1S: Sie: 4) 9) 6:

 

Answer:
10 A$ = “CHANGE A SENTENCE.”
20°: BS! = “EWS EASY: 107
30 C$ = BS + “” + AG
40 PRINT C$

50 Y = LEN (“A SENTENCE”)

60 FOR X = 1 TO LEN(C$) :
70 IF MID$ (C$,X,Y) = “A SENTENCE” THEN 90
80 NEXT X

85 END a

90 D$ = LEFT$ (C$,X - 1)

100 E$ = D$ + “ANYTHING YOU WANT”

110 PRINT E$

 

120
 

IF YOU LIKE A CHALLENGE, TRY a ih
Write a program in which:

1. The Computer asks you to INPUT:
a. a sentence
b. a phrase within the sentence to delete
c. a new phrase to replace the deleted phrase

2. The Computer then PRINTs a new sentence with your change intact.

This may take a while, but you have everything you need to write it. Our
answer is in the back of the book:

 

121
 

LEN
LEFT$
RIGHT$
MID$

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

122
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

123
| aaa

Dense

i va

===== CHAPTER 13 =====

 

BEAT THE COMPUTER

 

 
BEAT THE COMPUTER

You'll find the Computer much more adept by getting it to constantly watch
and react to everything you do. By “watching you”, we mean watching the
keyboard to see if you are pressing something. The word INKEY$ makes this
possible.

Type this:

10 A$ = INKEYS

20 IF A$ <>‘”’ GOTO 50

30 PRINT “YOU PRESSED NOTHING”

40 GOTO 10

50 PRINT “THE KEY YOU PRESSED IS---” AS

Press a key while RUNning this program.

INKEY$ tells the Computer to look at the keyboard to see if you have pressed
anything. The Computer does this with super-speed. You will have pressed
absolutely nothing for at least the first 20 times the Computer checks.

The Computer labels this key, or this non-key (“”), A$. Then the Computer
makes its decision:

If A$ equals “” — nothing — the Computer prints “YOU PRESSED NOTH-
ING” and goes back up to line 10 to check the keyboard again.

Remember what <> means? (It

means “not equal to”)

er)

means an empty string — nothing

125
 

126

 

However, if A$ equals something, the Computer goes to line 50 and prints the
key.

For a constant look-out, type this and RUN the program:
60 GOTO 10

No matter how quick you are, the Computer is much faster! Erase line 30 to see
what keys you’re pressing.

AN ELECTRONIC PIANO

Try using INKEY$ to make a piano out of your keyboard. Look at that table in
the Appendix, “Musical Tone Numbers’. It lists these as the tones for middle C
through the next higher C:

C - 89 E-125 G - 147 B-170
D - 108 F - 133 A-159 C-176

We can tell the Computer that if you press a certain key it should SOUND one
of these tones. Erase your program and type:

10 A$ = INKEY$

20 IF A$ = “” THEN 10

30 IF A$ = “A” THEN T = 89
40 IF A$ =“S” THEN T = 108
50 IF A$ =“D” THEN T = 125
60 IF A$ = “F” THEN T = 133
70 IF AS = “G” THEN T = 147
80 IF A$ = “H” THEN T = 159
90 IF A$ = “J” THEN T = 170
100 IF A$ = “K” THEN T = 176
110 IF T =O THEN 10

120 SOUNDT,5

130 T=0

140 GOTO 10
 

RUN the program . . . Well, what are you waiting for? Play a tune. Type any of
the keys on the third row down on your keyboard — from A to K.

Why wouldn’t the program work right if you use INPUT rather than INKEY$?

If you use INPUT the Computer will wait until you press (ENTER) before
acknowledging what you type. With INKEY$, it sees everything you type.

There’s another way of writing this program using READ and DATA lines. Do
you know how this would be done?

This is what we came up with:

10 A$ = INKEY$

20 FORX =1T08

30 READ B§, T

40 IF A$ = B$ THEN SOUNDT,5
50 NEXT X

60 RESTORE

70 GOTO 10

80 DATA A, 89, S, 108
90 DATA D, 125, F, 133
100 DATA G, 147, H, 159
110 DATA J, 170, K, 176

How would this change the program?
120 SOUND T, 1

Using these DATA and READ lines
will make it easier for you to add more
tones to your Computer’s repertoire.

127
128

 

BEAT THE COMPUTER
Type this program:

10 X = RND(4)

20 Y = RND(4)

30 PRINT “WHAT IS” X “+” Y
40 T=0

50 A$ = INKEY$

60 T=T+1

70 SOUND 128, 1

80 IF T = 15 THEN 200
90 IF AS = ‘”’ THEN 50
100 GOTO 10

200 CLS(7)
210 SOUND 180, 30
220 PRINT “TOO LATE”

Here’s what the program tells the Computer to do:

Lines 10, 20, and 30 gets the Computer to pick two random numbers and
ask you what their sum is.

Line 40 sets T to 0. We will use T as a timer.

Line 50 gives you your first chance to answer the question — in one
minute split second.

Line 60 adds 1 to the timer. T now equals 1. The next time the Computer
gets to line 60 it again adds 1 to the timer to make T equal 2. Everytime
the Computer executes line 60 it will add 1 to T.

Line 70’s just there to make you nervous.

Line 80 tells the Computer you have 15 chances to answer. Once T equals
15, time’s up. The Computer will insult you with lines 200, 210, and 220.

Line 90 says if you haven’t answered yet to go back and give you another
chance.

The Computer only gets to line 100 if you do answer. It will go back for
another problem.
 

How would you get the Computer to give you three times as much time to
answer each question?

Answer:
By changing this line:
80 IF T = 45 THEN 200

CHECKING YOUR ANSWERS

How would you get the Computer to check to see if your answer is correct?
Would this work?

100 IF A$ = X + Y THEN 130

110 PRINT “WRONG”, X “+ Y “="X + Y
120: GOTO 10

130 PRINT “CORRECT”

140 GOTO 10

If you RUN this program (and answer on time), you'll get this error message:

?TM ERROR IN 100

That’s because you can’t make A$, a string, equal to X + Y,numbers. You have

to somehow change A$ to a number.

Fortunately, your Computer has a way of doing this. Change line 100 by typing:
100 IF VAL(A$) = X + Y THEN 130

VAL(A$) turns A$ into its numeric VALue. If A$ equals the string “5”;

VAL(A$) equals the number 5. (However, if VAL(A$) equals the string “C”;
VAL(A$) equals 0 since “C” has no numeric value.)

Remember the problem of mixing
strings with numbers. Chapter 2 will
refresh your memory.

129
130

 

For those that want to make the program a bit more challenging, change these

lines:

10
20
90
100

X = RND(49) + 4

Y = RND(49) + 4

BS = BS + A$

IF VAL(B$) = X + Y THEN 130

And add these lines:

45
95

B$ = ws
IF LEN(B$) <> 2 THEN 50

A COMPUTER TYPING TEST

Here’s a program that will get the Computer to time how fast you type:

10
20
30
40
50
60
70
80
"90
"100
*110

120
130
140
150
160

CLS

INPUT “PRESS <ENTER> WHEN READY TO TYPE THIS PHRASE”; E$
PRINT “NOW IS THE TIME FOR ALL GOOD MEN”
T=1

A$ = INKEY$

IF A$ = ‘“”’ THEN 100

PRINT A$;

BS = BS + A$

IF LEN(B$) = 32 THEN 120

T= T+ 1

GOTO 50

S = T/74
M = S/60
= 8/M
PRINT
PRINT “YOU TYPED AT —“R”’—WDS/MIN”
 

Here’s how this program works:
In line 40, we set the timer — T — to 1.

Line 50 gives you your first opportunity to type a key — A$. If you’re not quick
enough, line 60 sends the Computer directly to line 100 and adds 1 to the
timer.

Line 70 prints the key you typed.

Line 80 forms a string named B$. Each time you type a key (A$), it will be
added to B$. For example, if the first key you type is “N”, then:

AS = “NY!

and
BS = B$ + A$
B$ = wa + NGS
B$ = “N’’

If the next key you type is “O”, then:

AS = MO!*

and
BS = BS + A$
B$ = MAI + Me
BS = “NO”

And if the third key you type is “W”, then:

A$ = “yw!

and
BS = “NO” + “W’
BS = “NOW”

When the LENgth of B$ equals 32 characters (the length of “NOW IS THE
TIME FOR ALL GOOD MEN”), the Computer assumes you've finished
typing the phrase and goes to line 120 to compute your words per minute.

131
 

Di isc We calculate the words per minute in lines 120, 130, and 140 by dividing T by
BRO FESS 74 (to get the seconds), S by 60 (to get the minutes), and then dividing the 8
| a words by M to get the rate of words per minute.

 
   

Change this program to get the Computer to check to see if you made a
typographical error.

 

Our answer is in the back of this book.

 
 

INKEY$
VAL

 

: NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

133
 
 

===== WHAT NOW? =====

Congratulations! By now, you should feel in full control of your Computer. You might be so busy
writing programs that you don’t want to read anything else yet.

It’s only fair to tell you that there are other BASIC words we haven’t covered. They are all listed
on your Quick Reference Card.

If you want more complete instructions on how to program, Radio Shack has plenty of good books:

BASIC Computer Language—catalog number 62-2016

BASIC Computer Programming—catalog number 62-2015

Level II Programming—catalog number 62-2061

Level II Programming Techniques—catalog number 62-2062

TRS-80 Assembly Language Programming—catalog number 62-2006
Understanding Digital Computers—catalog number 62-2027
Understanding Solid-State Electronics—catalog number 62-2035

These books are written at all different levels. Browse through them at your Radio Shack store to
see which are best for you.

135
 

136

===== APPENDIX A =====

 

MUSICAL TONES

Your Computer can come fairly close to matching (although it can’t exactly
match) the musical tones shown below. You may either use the piano keyboard
or the musical staff to produce electronic music.

If you’re using the piano keyboard, the Computer tone for each key is directly
over the key. For example, the Computer tone number for Middle C is 89.

If youre using the musical staff, the tone number for each note is below the
note. For example the tone number for:

 

is 108.

 

a Oo oO

6 EB) OD ani by gy SS BST Ss 3) 88.088 Rk me! BoB Se

Ww - o + ow © w © oOo - - - - - r _ - - + ~ - tr - -
MIDDLE

Ee eB be (ee Ber oR Wel Ae DfEE

 

 

 

 

 

 
 

If the note is a flat, select the tone number immediately preceeding the note.
For example:

 

is 99.

If the note is a sharp, select the tone number immediately following the note.
For example:

 

ISsLL7:

Chapter 5 shows how to program the Computer to play a song.

   

eR oO bn OMI =< EOE <a SRA 9 o co - © w - a - N + © R/O a - WN o
o °o o oO r rr xn N A N N Oo oO oO oO © |S eh i
- aS A AN DW DW xn A WA A AW N NWN AA AA Nn AA AAW

 

 

 

 

 

 

 

137
138

===== APPENDIX B =====

 

BASIC COLORS

These are the codes for each of the 9 colors you can create on the TRS-80
COLOR COMPUTER:

0 - black

1 - green

2 - yellow

3 - blue

4 - red

5 - buff

6 - cyan

7 - magenta
8 - orange

The color might vary in shade from these, depending on your T.V.

Color 0 is actually an absence of color. When using SET for graphics, color 0
will leave the cell’s color unchanged.


===== APPENDIX C =====

 

PRINT @ SCREEN LOCATIONS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

139
 

GRAPHICS SCREEN LOCATIONS

 

140
A

===== APPENDIX E =====

 

ANSWERS TO EXERCISES

CHAPTER 4

SOUNDing tones from bottom of range to top and back to

bottom:

10 FOR X = 1 T0.255

20 SOUND X,1

30 NEXT X

AO. FOR: Ai =o 255) 70: Li STEP (—1
50 SOUND X,1

60 NEXT X

CHAPTER 5
Lines added to clock program:

92: FOR ‘T= 200'.T0,210)STEP'5
94 SOUND T, 1

95: NEXT)

97 FOR T = 210 TO 200 STEP —5
98 SOUND T, 1

99 NEXT T

Program which Shows 9 colors for 1 second each:

10 FOR C = 070 8
20 CLS(C)

30 FOR X = 1 TO 460
40 NEXT X

50 NEXT C

CHAPTER 7
Craps Game

10 CLS

20 A RND(6)

30 B RND(6)

40 R=A+.B

50 PRINT @ 200, A

60 PRINT @ 214, B

70 PRINT @ 394, “YOU ROLLED A” R

80

90

100
110
120
130
140
150
160
170

180
185
190
200
210
220
225
230
240
250
260
270
280

500
510
515
520
530
540

600
610
615
620
630

IF R = 2 THEN 500
IF R = 3 THEN 500

IF R = 12 THEN 500

IF R = 7 THEN 600

IF R = 11 THEN 600

FOR X = 1 TO 800

NEXT X

CLS

PRINT @ 195, “ROLL ANOTHER” R “AND YOU WIN‘
PRINT @ 262, “ROLL A 7 AND YOU LOSE”
PRINT @ 420, “PRESS <ENTER> WHEN READY’
PRINT @ 456, “FOR YOUR NEXT ROLL”
INPUT A$

X = RND(€)

Y = RND&(€)

Z=X+Y

CLS

PRINT @ 200, X

PRINT @ 214, Y

PRINT @ 394, “YOU ROLLED A” Z

IF Z = R THEN 500

IF Z = 7 THEN 600

GOTO 180

FOR X = 1 TO 1000

NEXT X

CLS

PRINT @ 230, “YOU'RE THE WINNER”
PRINT @ 294, “CONGRATULATIONS!!!”
GOTO 630

FOR X = 1 TO 1000

NEXT X

CLS

PRINT @ 264, “SORRY, YOU LOSE”
PRINT @ 458, “GAME’S OVER”

141
 

Russian Roulette program:

5 FOR N = 117010

10 PRINT “CHOOSE YOUR CHAMBER(1-10)”
20 INPUT X

30 IF X = RND(10) THEN 100

40 SOUND 200, 1

50 PRINT “—CLICK—”

60 NEXT N

65 CLS

70 PRINT @ 230, “CONGRATULATIONS!!!”
80 PRINT @ 265, “YOU MANAGED”

90 PRINT @ 296, “TO STAY ALIVE”

95 END

100 FOR T = 133 TO 1 STEP —5

110 PRINT “BANG!!!!1”

120 SOUND T, 1

130" “NEXT: 7

140 CLS

150 PRINT @ 230, “SORRY, YOU’RE DEAD”
160 SOUND 1, 50

170 PRINT @ 390, “NEXT VICTIM, PLEASE”

142

CHAPTER 10

Test

5

6

8
10
15
20
30
40
45
50
60
70
80
82
83
84
85
86
87
90
95
OF
98
o9
100
102
105
110

Your Arithmetic Program

CLS
PRINT @ 230, “YOUR NAME”;
INPUT N$
CLS
ToS Tie
X = RND(100)
Y = RND(100)
PRINT @ 228, “WHAT IS” X “4” Y;
INPUT A
IF A = X + Y THEN 82
PRINT @ 326, “THE ANSWER IS” X + Y
PRINT @ 385, “BETTER LUCK NEXT TIME,” N$
GOTO 100
CLS(7)
FOR M = 1104
SOUND 175, 1
SOUND 200, 1
NEXT M
CLS
PRINT @ 232, “CORRECT,” N$ “II!”
C= iti4 1
PRINT @ 299, “THAT IS”
PRINT @ 322, C “OUT OF” T “CORRECT ANSWERS”
PRINT @ 362, C/T*100 “% CORRECT”
PRINT @ 420, “PRESS <ENTER> WHEN READY”
PRINT @ 458, “FOR ANOTHER”
INPUT A$
GOTO 10
 

CHAPTER 11 CHAPTER 13

Table of Squares Computer Typing Test
D\/CLS 10; CLS
7 PRINT @ 38, “TABLE OF SQUARES” 20 INPUT “PRESS <ENTER> WHEN READY TO TYPE
8 PRINT THIS PHRASE”; E$
10 P =2 30 PRINT “NOW IS THE TIME FOR ALL GOOD MEN”
20 FOR N =2 TO 10 40: T’="1
25 GOSUB 2000 50 AS = INKEY$
30: PRINT Nie Ae Ee. 60 IF A$ = ‘” THEN 100
40 NEXT N 70 PRINT A$;
50 END 80 BS = BS + A$
2000 REM FORMULA FOR RAISING A NUMBER TO 90 IF LEN(B$) = 32 THEN 120
A POWER 100 T= 7T +51
20103 B= 110 GOTO 50
20200, FOR! X= Ji FOeP 120 S = T/74
20305 Eva 76: 2 oN 130 M = S/60
2040 NEXT X 140 R = 8/M
2050 IF P = 0 THEN E = 1 142 FOR X = 1 TO 32
2060 RETURN 144 IF MIDS(“NOW IS THE TIME FOR ALL GOOD
MEN”,X,1) <> MID$(B$,X,1) THEN E = E + 1
CHAPTER 12 146 NEXT X
Editing a Sentence 150 PRINT
160 PRINT “YOU TYPED AT—” R ‘“—WDS/MIN”
10 ‘PRINT. “TYPE A. SENTENCE ;’':;S$ 170 PRINT “WITH” E “ERRORS”
15 INPUT S$
20 PRINT “TYPE A PHRASE TO DELETE”
23 INPUT D$

25 L = LEN(D$)

30 PRINT “TYPE A REPLACEMENT PHRASE”

35 INPUT R$

40 FOR X = 1 TO LEN(SS)

50 IF MID$(S$,X,L) = D$ THEN 100

60 NEXT X

70 PRINT D$ “— IS NOT IN YOUR SENTENCE”

80 GOTO 20

100 E = X — 1 + LEN(D$)

110 NS$ = LEFT$(S$,X—1) + R$ + RIGHTS(S$,LEN(S$)
Sue

120 PRINT “NEW SENTENCE IS :” ad
130 PRINT NS$
APPENDIX F

 

===== SAMPLE PROGRAMS =====

SPEED READING MUSIC COMPOSER
20 INPUT “LENGTH(1-10)”; M

10 REM * SPEED READING * 25. M.=.M-*'4
20 CLS : PRINT @ 32, ‘HOW MANY WORDS PER MINUTE” 30 INPUT “TEMPO (1-4)”; T1
30 INPUT “DO YOU READ’; WPM 40 .IF Tl = 4 THEN 60
40 FOR X = 1 TO 23 50°. T.. = -TL ="GOT0::70
50 REM (23 LINES OF TEXT) 60: T= 8
60 READ A$ : PRINT @ 256, A$ 70° -FOR-K, =: 70) M*8
70 FOR Y = 1 TO (360/WPM) * 460 : NEXT Y 80 GOSUB 1000
80 REM Y LOOP SETS LINES/MINUTE 90: B. = -RNDG)* FT
90 NEXT X : END 100 SOUND P, B
100 DATA SCARLETT OHARA WAS NOT BEAUTIFUL 110 CLS(S)
110 DATA BUT MEN SELDOM REALIZED IT WHEN 120 NEXT K
120 DATA CAUGHT BY HER OWN CHARM AS THE 130 IF RND(10) <=8 THEN 150
130 DATA TARLETON TWINS WERE. IN HER FACE 140 SOUND 125, 16*T
140 DATA WERE TOO SHARPLY BLENDED 145 END
150 DATA THE DELICATE FEATURES OF HER 150 SOUND 90, 16*T
160 DATA MOTHER, A COAST ARISTOCRAT OF 160 END
170 DATA FRENCH DESCENT, AND THE HEAVY 1000 X = RND(100)
180 DATA ONES OF HER FLORID IRISH FATHER 1010 IF X <= 20 AND X <= 25 THEN P = 90:S = 1
190 DATA BUT IT WAS AN ARRESTING FACE, 1020 IF X > 20 AND X <= 25 THEN P = 108: S = 2
200 DATA POINTED OF CHIN, SQUARE OF JAW 1030 IF X > 25 AND X <= 40 THEN P = 125: 5S = 3
210 DATA HER EYES WERE PALE GREEN 1040 IF X > 40 AND X <= 55 THEN P = 133: S = 4
220 DATA WITHOUT A TOUCH OF HAZEL, 1050 IF X > 55 AND X <= 75 THEN P = 147:S = 5
230 DATA STARRED WITH BRISTLY BLACK 1060 IF X > 75 AND X <= 85 THEN P = 159: S = 6
240 DATA LASHES AND SLIGHTLY TILTED 1070 IF X > 85 AND X <= 95 THEN P = 176:S = 7
250 DATA THE ENDS, ABOVE THEM, HER THICK 1080 IF X > 95 THEN P = 58:S = 8
260 DATA BLACK BROWS SLANTED UPWARDS, 1090 RETURN

270 DATA CUTTING A STARTLING OBLIQUE LINE
280 DATA IN HER MAGNOLIA-WHITE SKIN—THAT
290 DATA SKIN SO PRIZED BY SOUTHERN WOMEN
300 DATA AND SO CAREFULLY GUARDED WITH
310 DATA BONNETS, VEILS, AND MITTENS

320 DATA AGAINST HOT GEORGIA SUNS.

144
—

READY, AIM, FIRE

10

20

30

40

50

60

70

80

90

100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
272
274
276
280
290
300
310
320
330
340
350

CLS : PRINT

PRINT “HIT ‘Z’ KEY TO AIM LEFT”
PRINT “HIT Y’ KEY TO AIM RIGHT”
PRINT “HIT SPACE BAR TO FIRE”
FOR K = 1 TO 3000 : NEXT K
CLS(0)

CA = 464

PRINT @ CA, “*”;

PRINT @ 495, “***"

PRINT @ 32, “ ”

F=0

PRINT @ 32 +1* 4,” i
IF 1 > 6 THEN I = 0

I = I + RND(1O)/10

PRINT @ 32 + 1 * 4, \—>";

IF F = 0 THEN 500
RESET(MX,MY)

MX = MX — MD

MY = MY - 8

IF MX < 1 THEN 110

IF MX > 63 THEN 110

IF MY > 2 THEN SET(MX,MY,5) : GOTO 120
IF ABS(I*8-MX) > 4 THEN 110

FOR J = 1106

PRINT @ 32+4*], “****”;

FOR K = 1 TO 50

NEXT K

PRINT @ 32 + 1* 4 ™ u

FOR K = 1 TO 50

NEXT K

NEXT J

FOR K = 200 TO 10 STEP -3
SOUND K, 1

NEXT K

FOR K = 1 T0 7 : CLS(K)

FOR KK = 1 TO 50: NEXT KK
NEXT K
CLS(0)

360 GOTO 60

500 Y$ = INKEY$

510 IF F = 1 THEN END
520) TE Ye rhe THEN: 550
530 IF CA < 462 THEN 120
540 PRINT @ CA, CHR$(160);
545 CA = CA - 1

547 GOTO 580

550° IF Y$ <>'"Y" THEN 590
560 IF CA > 466 THEN 120
570 PRINT @ CA, CHR$(160);
575 CA = CA + 1

580 PRINT @ CA, “*”; : GOTO 120
BIO RAY Seer he THEN 120
600 F = 1: MD = 464 — CA: MY = 20
610 MX = 32 — 3 * MD: SET(MX,MY,3) : GOTO 120
620 END

KALEIDOSCOPE

10 CLS(O)

20 X = RND(32) —- 1

30 Y = RND(16) —- 1

40 Z = RND(Y) - 1

50 GOSUB 90

60 GOTO 20

90 IF Z = O THEN 150

95 IF RND(7) = 3 THEN 150
LOG: SETS) 164) 2)

110; SERGE X15 V 2)

12D SRT AK, 16 ¥)) 2)

150; SETG2+%; 15 'Y,, Z)

140 RETURN

150’: RESERGI— xX, 16+ Y)

160: RESET(31— X;,15.--Y)

170 RESET(32+X, 16+Y)

180 -RESETG2+X, 15~Y)

190 RETURN

145
146

===== APPENDIX G =====

 

ERROR MESSAGES

The shaded errors are the errors you are most likely to come across while going through this
book. While you might get some of the non-shaded errors, they are usually caused by more
advanced programming techniques.

AO Attempt to open a data file which is already open.

BS Bad subscript. The subscripts in an array are out of range. Use DIM to dimension the
array. For example, if you have A(12) in your program, without a preceeding DIM line
which dimensions array A for 12 or more elements, you will get this error.

CN Can’t continue. If you use the command CONT and you are at the END of the program,
you will get this error.

DD Attempt to redimension an array. An array can only be dimensioned once. For example,
you cannot have DIM A(12) and DIM A(50) in the same program.

DN Device number error. Only three devices may be used with OPEN, CLOSE, PRINT, or
INPUT: 0, —1, or — 2. If you use another number you will get this error.

 

FD Bad file data. This error occurs when you PRINT data to a file, or INPUT data from the
file, using the wrong type of variable for the corresponding data. For example, INPUT
# —1, A, when the data in the file is a string, causes this error.

FM Bad file mode. This error occurs when you attempt to INPUT data from a file OPEN for
OUTPUT (0), or PRINT data into a file OPEN for INPUT (I).

|

 
 

IE Input past end of file. Use EOF to check to see when you’ve reached the me of the file.
When you have, CLOSE it.

 

NO File not open. You cannot input or output data to a file until you have OPENed it.

 

147

===== APPENDIX H =====

 

BASIC- SUMMARY

This appendix contains the BASIC words, keyboard characters, symbols, and operators that we’ve explained
in this book. For a complete listing of them, see the COLOR BASIC Quick Reference Card.

BASIC WORDS

WORD
CLOAD

CLS

CSAVE

DATA

END

FOR. .TO
STEP/
NEXT

GOSUB

GOTO
148

PURPOSE

Loads the first program from
cassette tape. You may specify
the name of the program.

Clears the screen to green, or
to the color code you specify.
See Appendix B for a list of
the color codes.

Saves a program on cassette
tape. You may use a program
name with up to 8 letters.

Stores data in your program.
Use READ to assign this data
to variables.

Ends your program.

..Creates a loop in your program

which the Computer must repeat
from the first number to the

last number you specify. You may
use STEP to specify how much to
increment the number each time
through the loop. If you omit
STEP, 1 is the increment.

Sends the Computer to the
subroutine beginning at the line
number you specify.

Sends the Computer to the line
number you specify.

CHAPTER

EXAMPLES DISCUSSED
CLOAD 8
CLOAD “PROGRAM”
CLS 1
CLS(2)
CSAVE 8
CSAVE “PROGRAM”
DATA 5, 3, PEARS 10
DATA PAPER, PEN
END 6
FOR X = 2705 4&5

/NEXT X
FOR A=1 TO 10 STEP5

/NEXT A
FOR M = 30 TO 15 STEP —5

NEXT M
GOSUB 500 11
GOSUB 5000
GOTO 300 3
 

IF/THEN

INKEY$

INPUT

INT
JOYSTK

LIST

NEW
PEEK

PRINT

PRINT @

READ

Tests the relationship. If it
is true, the Computer executes
the instruction following THEN.

Strobes the keyboard and returns
the key or non-key being pressed.

Causes the Computer to stop and
await input from the keyboard.

Converts a number to an integer.

Returns the horizontal or

vertical coordinate of the left

or right joystick:
0—horizontal, left joystick
1—vertical, left joystick
2—horizontal, right joystick
3—vertical, right joystick

Lists the entire program, or
the lines in the program you
specify.

Erases everything in memory.

Returns the contents in the
memory location you specify.

Prints the message you specify
on the video screen.

Prints your message at the
screen position you specify.
See Appendix C for the screen
positions.

Reads the next item in the DATA
line and assigns it to the
variable you specify.

IF A=5 THEN 300
IF BS=“YES” THEN
PRINT “XYZ”

A$= INKEY$

INPUT X$
INPUT “NAME”; N$

X= INT(5.2)

M=JOYSTK(O)
H = JOYSTK(2)

LIST

LIST 50-85
LIST 30
LIST —30
LIST 30-—

NEW
A= PEEK(32076)

PRINT “HI”
PRINT A$ PRINT A

PRINT “HI”, 256
PRINT A$, 331

READ A$
READ C, B

13

3&11

10

10

149
 

REM

RESET

RESTORE

RETURN

RND

RUN

SET

SKIPF

SOUND

VAL

150

Allows you to insert a comment
in your program. The Computer
ignores everything on a REM line.

Erases the dot SET on the screen
location you specify. See
Appendix D for the screen
locations.

Sets the Computer’s pointer back
to the first item on the DATA
lines.

Returns the Computer from the
subroutine to the BASIC word
following GOSUB.

Returns a random integer between
1 and the number you specify.

Executes a program.

Sets a dot at the screen location
you specify, using the color you
specify. See Appendix D for the
screen locations and Appendix B
for the color codes.

Skips to the end of the next
program on cassette tape, or
to the end of the program you
specify.

Sounds the tone you specify for
the duration you specify. Both
the tone and the duration may be
a number between 1 and 255.

Converts a string to a number.

REM THIS IS IGNORED

RESET(14,15)

RESTORE

RETURN

A=RND(10)

RUN

SET(14,13,3)

SKIPF
SKIPF “PROGRAM”

SOUND 128, 3

A=VAL(B$)

11

10

tt

1&5

13
 

KEYBOARD CHARACTERS BASIC OPERATORS

CHAPTER CHAPTER
CHARACTER PURPOSE ; DISCUSSED OPERATOR PURPOSE DISCUSSED
& Backspaces the cursor 1 + Combines strings 12
(the blinking light) He Addition 1
ENTER Tells Computer you’ve reached 1&3 re Subtraction 1
the end of your program line * Multiplication 1
or command line. / Division 1
; = Equals 1
BREAK Stops execution of your program. 3 se Gééeater Than 9
Pauses execution of your program. 4 >= or => Greater than or equal to 9
Press any key to continue. <= or =< Less than or equal to 9
Less than 9
<> or >< Not equal to 13
BASIC SYMBOLS
CHAPTER
SYMBOL EXPLANATION DISCUSSED
Rei Indicates that the data in 1
quotes is a constant.
Separates program “statements” 11
on the same line.
G) Tells the Computer to perform 11

the operation in the inside
parenthesis first.

151
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES: |

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
===== RADIO SHACK SOFTWARE LICENSE =====

The following are the terms and conditions of the Radio Shack Software License for copies of Radio Shack
software either purchased by the customer, or received with or as part of hardware purchased by customer:

A. Radio Shack grants to CUSTOMER a personal, non-exclusive, paid up license to use the Radio Shack
computer software programs received. Title to the media on which the software is recorded (cassette
and/or disk) or stored (ROM) is transferred to the CUSTOMER, but not title to the software.

B. Inconsideration for this license, CUSTOMER shall not reproduce copies of such software programs except
to produce the number of copies required for personal use by CUSTOMER (if the software allows a backup
copy to be made), and to include Radio Shack’s copyright notice on all copies of programs reproduced in
whole or in part.

C. CUSTOMER may resell Radio Shack’s system and applications software (modified or not, in whole or in
part), provided CUSTOMER has purchased one copy of the software for each one resold. The provisions of
this Software License (paragraphs A, B, and C) shall also be applicable to third parties purchasing such
software from CUSTOMER.

IMPORTANT NOTE

All Radio Shack computer programs are licensed on an ‘‘as is’’ basis without warranty.

Radio Shack shall have no liability or responsibility to customer or any other person or entity with respect to
any liability, loss or damage caused or alleged to be caused directly or indirectly by computer equipment or
programs sold by Radio Shack, including but not limited to any interruption of service, loss of business or
anticipatory profits or consequential damages resulting from the use or operation of such computer or
computer programs.

Good data processing procedure dictates that the user test the program, run and test sample sets of data, and
run the system in parallel with the system previously in use for a period of time adequate to insure that results
of operation of the computer or program are satisfactory.


RADIO SHACK Ba A DIVISION OF TANDY CORPORATION

   

U.S.A. CANADA
FORT WORTH, TEXAS 76102 BARRIE, ONTARIO, L4M4W5

 

TANDY CORPORATION

AUSTRALIA BELGIUM UNITED KINGDOM
280-316 VICTORIA ROAD PARC INDUSTRIEL NANINNE _ BILSTON ROAD, WEDNESBURY
RYDAMERE, N.S.W. 2116 5140 NANINNE WEST MIDLANDS WS10 7JN
Color Computers

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