Commodore PET - Boolean Operators

ELEMENTS
Before modifying this display program further, we will set it as ide and de-
scribe the elements of
PET BASIC. This will introduce vou to the full range of
statements, functions, and commands available. At the end of the chapter we will
come back to this display example and show how vou can develop it into a stored
program.
Like natural languages,
PET BASIC has an alphabet consisting of letters,
numbers, and special characters. These correspond to the alphabetic keys,
numeric keys, and special symbol keys
on the PET keyboard. The remaining
two groups of keys, graphie keys and function keys, may be used only inside
quotation marks, or for keyboard/cursor control purposes not related to the BASIC
language.
The PET alphabet is used to form the words, numbers, and other ele-
ments
that make up a BASIC sentence, or statement.
NUMBERS
Vou use numbers ail the time when working with the PET. There are two
kinds of numbers that can be stored in the PET: floating point numbers (also
called ~eal numbers) and integers.
Floating Point Numbers
Floating point is the standard number representation used by the PET. The
PET does its arithmetic using floating point numbers. A floating point number
can be a whole number, a fractional number preceded by a decimal point,
or
a combination. The number can be signed negative (-) or positive (+). If the
number has no sign it is assumed to be positive. Here are some examples of float-
ing point numbers:
Whole number, equivalent to an integer:
5
-15
65000
161
o
53