Commodore 128D - Page 343

Variables
The Commodore 128 uses three types of variables in BASIC. These
are: normal numeric, integer numeric and string (alphanumeric).
Normal NUMERIC VARIABLES, also called floating point variables,
can have any value from **superscript** - 10 to ^super
script* * +10, with up to nine digits of accuracy. When a number
becomes larger than nine digits can show, as in + 10 or - 10, the
computer displays it in scientific notation form, with the number nor
malized to one digit and eight decimal places, followed by the letter E
and the power of 10 by which the number is multiplied. For example,
the number 12345678901 is displayed as 1.23456789E +10.
INTEGER VARIABLES can be used when the number is from
+ 32767 to - 32768, and with no fractional portion. An integer varia
ble is a number like 5,10 or -100. Integers take up less space than
floating point variables, particularly when used in an array.
STRING VARIABLES are those used for character data, which may
contain numbers, letters and any other characters the Commodore
128 can display. An example of a string variable is "Commodore
128."
VARIABLE NAMES may conaist of a single letter, a letter followed by
a number or two letters. Variable names may be longer than two
characters, but only the first two are significant. An integer is speci
fied by using the percent sign (%) after the variable name. String
variables have a dollar sign ($) after their names.
EXAMPLES:
Numeric Variable Names: A, A5, BZ
Integer Variable Names: A%, A5%, BZ%
String Variable Names: A$, A5$, BZ$
ARRAYS are lists of variables with the same name, using an extra
number (or numbers) to specify an element of the array. Arrays are
defined using the DIM statement and may be floating point, integer
or string variable arrays. The array variable name is followed by a set
of parentheses () enclosing the number of the variable in the list.
EXAMPLE:
A(7), BZ%(11), A$(87)
Arrays can have more than one dimension. A two-dimensional array
may be viewed as having rows and columns, with the first number
identifying the row and the second number identifying the column
(as if specifying a certain grid on a map).
335 BASIC 7.0 ENCYCLOPEDIA—Variables and Operators