Atari 800 - Page 9

TERMINOLOGY
1
GENERAL
INFORMATION
This section explains BASIC terminology, special notations , and abbre v iation s
used in this manual, and the special keys on the AT ARI 400™ and AT ARI 800 ™
Personal Computer Systems keyboard . It also points to other sections where
BASIC commands deal with specific applications.
BASIC: Beginner's All-purpose Symbolic Instruction Code.
BASIC Keyword: Any reser v ed word "legal " in the BASIC language. May be
used in a statement , as a command, or for any other purpose. (See Appendi x A
for a list of all "reserved words" or keywords in AT ARI BASIC.)
BASIC Statement: Usually begins with a keyword , like LET, PRINT, or
RUN.
Constant: A constant is a value expressed as a number rather than represented
by a variable name . For example, in the statement X = 100 , X is a v ariable and
100 is a constant. (See Variable.)
Command String: Multipl e commands (or pr o gr am st at em e nt s) pl ac ed on th e
same numbered line separated by colons.
Expression: An e xpression is i my le gal c ombin a tion of va riables , c onstan ts,
operators, and functions used together to compute a value. Expressions can be
either arithmetic, logical, or string .
Function: A function is a computation built into the computer so that it can be
called for by the user 's program. A function is NOT a statement ; it is part of an
expressi o n. It is r ea lly a subroutin e used to c omput e a va lu e which is then
"returned" to the main program when the subroutine returns. COS (Cosine),
RND (random), FRE (unused memory space), and INT (integer ) are ex amples of
functions . In man y cases th e v alue is s impl y as sign ed to a va riabl e (stored in a
var iable) for lat er use. In other ca s es it may be print ed out on th e scr een im-
mediately. See Section 6 for more on functions. Examples of functions as they
might appear in programs are:
10 PF.:HH F.l[l( 0)
( print ou t the random
numb er ret urn ed)
(add
the value re-
r et urn ed to 100 a nd
sto re the to ta l in
variable
X)
General In fo r ma tion 1