Returns TRUE if an expression is false, and FALSE if an expression is true.
Syntax
NOT expression
expression
A logical expression whose value is logical, that is TRUE/FALSE, YES/NO.
Example
In this procedure, if the user enters the number of a Customer that does not exist, the procedure displays a message that the Customer does not exist and the user must try again. If the Customer does exist, the procedure displays the Name and Phone number of the Customer.
r-not.p
REPEAT:
PROMPT-FOR Customer.CustNum.
FIND Customer USING Customer.CustNum NO-ERROR.
IF NOT AVAILABLE customer THEN DO:
MESSAGE "Customer with CustNum:" INPUT Customer.CustNum
" does not exist. Please try another.".
UNDO, RETRY.
END.
ELSE
DISPLAY Customer.Name Customer.Phone.
END.
