QBasic Programming

CLS
INPUT "ENTER FIRST STRING"; A$
INPUT "ENTER SECOND STRING"; B$
INPUT "ENTER THIRD STRING"; C$
IF LEN(A$) > LEN(B$) AND LEN(A$) > LEN(C$) THEN
G$ = A$
IF LEN(B$) > LEN(A$) AND LEN(B$) > LEN(C$) THEN
G$ = B$
ELSE
G$ = C$
END IF
PRINT "LONGEST STRING="; G$
END

USING SUB PROCEDURE
DECLARE SUB LON ( A$, B$, C$)
CLS
INPUT "ENTER FIRST STRING"; A$
INPUT "ENTER SECOND STRING"; B$
INPUT "ENTER THIRD STRING"; C$
CALL LON(A$, B$, C$)
END

SUB LON (A$, B$, C$)
IF LEN(A$) > LEN(B$) AND LEN(A$) > LEN(C$) THEN
G$ = A$
IF LEN(B$) > LEN(A$) AND LEN(B$) > LEN(C$) THEN
G$ = B$
ELSE
G$ = C$
END IF
PRINT “LONGEST STRING=”; G$
END SUB
USING FUNCTION PROCEDURE
DECLARE FUNCTION LON$( A$, B$, C$)
CLS
INPUT "ENTER FIRST STRING"; A$
INPUT "ENTER SECOND STRING"; B$
INPUT "ENTER THIRD STRING"; C$
PRINT "LONGEST STRING="; LON$( A$, B$, C$)
END
FUNCTION LON$( A$, B$, C$)
IF LEN(A$) > LEN(B$) AND LEN(A$) > LEN(C$) THEN
G$ = A$
IF LEN(B$) > LEN(A$) AND LEN(B$) > LEN(C$) THEN
G$ = B$
ELSE
G$ = C$
END IF
LON$ = S$
END FUNCTION