Commodore VIC-20 - Page 75

fact, the way they are handled by the VIC. A variable name
represents an address in memory; and at that memory location, the
current value of the variable is stored. The important point to note is
that variable names—which are names that programmers make
up—are
arbitrary; they have no innate relationship to the value that
the variables represent.
A variable name can have one or two characters. The first
character must be an alphabetic character from A to Z; the second
character can be either alphabetic or numeric {numeric characters
must be in the range from 0 to 9). A third character can be included
to indicate the type of number (integer or string), % or S.
Floating variables represent floating point numbers. This is
probably the most common type of variable that you will use.
The following are examples of floating point variables:
A
B
A1
AA
Z5
Integer variables represent integers. Names for integer variables
are followed by the % symbol as the following examples indicate:
A%
B%
A1%
MN%
X4%
Remember, floating point variables can also represent integers;
but you should use integer variables in arrays whenever possible
since they use less memory—two bytes versus five for a floating
point array element.
A string variable represents a string of text. The following are
examples of string variables:
A$
M$
MNS
M1$
2XS
F6S
You can use variable names having more than two alphanumeric
characters; but if you do, only the first two characters count. To VIC
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