.-. oo— — a izk. Amelia

ASIC words

e jsa listofthe BASIC words used in this book, with short explanations
ha! they mean. Some of the words, such as CLS, are not standard on
-omputers and these words have a small star beside them. lfyou have
cro you should check these commands in your manual

z Onsome computers this stops the program running. Be careful, though, on

rs it erases the whole program from the computer's memory and you shoulduse

"A PE, or some other word instead.

- Clears the screen.

A list of items, e.g. words or numbers, to be stored by the computer in
ibles. See READ

| Tells the computer how many memory spaces it should set aside for a variable.
DIM A$4(5,4) means the vanable needs five rows of four columns.

| Allows you toalter aline ina program without typing in the whole lineagain.

— Tells the computer it is the end of a program. Some computers must always have
D statement, others, such as the BBC micro and Sinclair computers, do notneed

.. NEXT. Makesthe computer loop back through the programand repeat any
pctions inside the loop a fixed number of times.

UE Makes the computer leave the main part of the program and go to a part called
aroutine to CaITy out a special task.

) Tells the computer to go to another line in the program.

 THEN Compares pieces of data (e.g. numbers or words or the contents of
les) and does different things depending on the results.

| A way of getting the computer to ask you for data while the program is running.

Converts a number with a decimal point to a whole number by ignoringaallthe
to the right of the decimal point. E.g. INT(3.40) —3.

Tells the computer to do something with a number of characters fromthe
side ofa string. E.g. LEFT$(A$,4) means take four characters from the leftof A$.

Gives the length ofa string, i.e. the number of characters in avariable.

iIPuter words

K set of variables containing several pieces of data.
pečata in a program.
P a processing unit of the computer which controls all the operationsand
j Work, «9 Comparing variables, adding, etc.
small, sometimes fashing light,
where be ga ar a V e or other shape on the screenwhich
a chart showing the main
ie si | operations needed in a program. Often usedas
»a Ways of producing information visually on the screen.
(basi A unit of measurement for the memory ofa computer. One kilobyte is
A in most micros each character takes up onebyte.
a Mana 9n mark or other symbol which appears on the screen whenthe
Or information after an INPUT statement.

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LET Putsavariablelabel ona memory space and put
N- 4or LETB$-"CATS". PIANO

% LIST Displaysthe program listing on the screen

% MID$ Tells the computer to do something with characters trom the middle of a string
E.g. MID$(A$,4,3) means take three letters starting from the fourth letter of AS.

NEW  Wipes the program from the computer's memory to clear it for the next
program.

$ NEWLINE KEY Tellsthe computer that you have finished typing ina program line or
piece of input. Some computers have keys marked RETURN or ENTER.

NEXT SeeFOR.

$ PLOT Tellsthe computer to light up a pixel. E.g. PLOT (X,Y) means light up the pixel
with co-ordinates X along and Y up.

information in it. E.g LET

PRINT  Tells the computer to display something on the screen.

$ READ Tellsthe computer to read the information in a DATA line and store itina
variable. See DATA.

4 READY Some computers say this when they are ready to be given another instruction
REM The computer ignores lines starting with REM but displays them in the program
listing. They are useful to remind you what different parts of the program do.

RETURN  Atthe end ofa subroutine, tells the computer to go back to the instruction
after the one where it left. See GOSUB.

4 RIGHT$  Tells the computer to do something with the right-hand characters in a strmg.
E.g. RIGHT$(A$,4) means take the four characters from the right oLA$.

— $RND Picksa random number.

RUN Tells the computer to carry out a program.

SOR Tellsthe computer to find the sguare root of a number.

STEP Usedwith FOR ... NEXT loops. Tells the computer when to repeat the loop.
STOP Usedwithin a program to tel] the computer to stop runningthe program.
THEN SeelF.

x UNPLOT  Tells the computer to switch offa pixel.

Pixels Short for picture elements. The small sguares which the computer can light up
oe ra mberad list ofinstructionstellingthe computer how to carry outa

and data are stored. All the information in RAM is automatically erased when the
a A Mico Permanent memory where information telling the

error AmistakeintheBASICintheprogram. |
Varable Alabelled memory space which containsa piece olinionmanom