LOGO-L> QUESTION ON CONDITIONAL OUTPUTS

[PZeidenber <PZeidenber@aol.com>]

IN THE TWO FOLLOWING PROCEDURES:

TO ADDLISTS :LIST1 :LIST2 :LIST3
IF EMPTY? :LIST1 [OP :LIST3] 
MAKE "A1 FIRST :LIST1 
MAKE "A2 FIRST :LIST2 
MAKE "S :A1 + :A2 
ADDLISTS BF :LIST1 BF :LIST2 LPUT :S :LIST3 
END

AND

TO ?ADDLISTS :LIST1 :LIST2 :LIST3
IF EMPTY? :LIST1 [PRINT (LIST :LIST3) STOP]
MAKE "A1 FIRST :LIST1
MAKE "A2 FIRST :LIST2
MAKE "S :A1 + :A2
?ADDLISTS BF :LIST1 BF :LIST2 LPUT :S :LIST3
END

ONLY THE SECOND PRINTS THE ANSWER. THE FIRST OUTPUTS BUT ALSO GIVES AN ERROR
METHODS AND THE OUTPUT CANNOT BE PASSED TO ANOTHER PROCEDURE. (USING UCB LOGO
4.5 OR LOGO PLUS) CAN ANYONE HELP ME WITH THIS PROBLEM?

PHILLIP ZEIDENBERG PZEIDENBER@AOL.COM
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