Commodore Plus 4 - Unpacking your Commodore Plus;4

Z The BASIC Language
Function A function is a text string or numeric operation that returns a value.
You can use any of the functions that are part of BASIC, and you can create your
own with the DEF FN command.
Operator We use the term operator to mean a symbol or keyword (such as
AND) that performs a mathematical task or compares two values. The types of
operators available in BASIC are mathematical, comparison, and logical.
Parameter A parameter is a nonkeyword part of a BASIC command or func
tion. Parameters usually have multiple possible values. You supply the parameter
to define the way you want to use the BASIC command. Some parameters must
be used in a command and many others are optional.
Default Some parameters have a default value, which means that a certain
value is automatically used for that parameter if you do not specify some other
value. To select the default value, you can generally just omit the parameter. In
some commands, such as CIRCLE, you must type a placeholder comma for a
default value if additional parameters follow the default. For example, to accept
the default value for the color source in a CIRCLE command, type a comma in
the color source position. The color source is the first parameter, so the command
could look like this: CIRCLE, 160,100,60,50.
Expression Occasionally we will use the term expression to mean a number or
string.that can be a constant, variable, or function that results in an appropriate
value.
Constants and Variables
Constants are data values that you can use in a BASIC command. Variables are
symbolic names that stand for one or more possible values in a BASIC command.
For example, in the command PRINT "TOTAL:";T, the character string TOTAL
is a constant and T is a variable that stands for the numeric value being printed.
BASIC 3.S accepts three types of constants and variables:
1. Integer numbers (whole numbers)
2. Floating-point nuijibers (decimal numbers)
3. Character strings (text)