Specifications

Chapter 14. Statement Reference
194
Syntax:
Syntax 1 (Defining a numeric function):
DEF FNfunctionname[(dummyparameter[,dummyparameter
...])]=expression
Syntax 2 (Defining a string function):
DEF FNfunctionname[(dummyparameter
[,dummyparameter...])] [[stringlength]]=expression
Syntax 3 (Calling the function):
FNfunctionname[(realparameter[,realparameter ...])]
Parameter:
functionname
•For numerics
functionname% Integer function name
functionname Real function name
•For strings
functionname$ String function name
where the FN can be in lowercase.
dummyparameter
A non-array integer variable, a non-array real variable, or a non-array string
variable.
stringlength
An integer constant having a value from 1 to 255.
expression and realparameter
A numeric or string expression.
DEFine FuNction User-defined function definition statement
DEF FN (Single-line form)
Names and defines a user-defined function.