POB 算法 递归之 Fibonacci数列

#COMPILE EXE
#DIM ALL

FUNCTION Fib(BYVAL n AS LONG)AS LONG
    IF n<= 1 THEN
        FUNCTION = n
    ELSEIF n>1 THEN
        FUNCTION =  Fib(n-1)+  Fib(n-2)
   END IF
END FUNCTION
FUNCTION PBMAIN () AS LONG
    DIM rtn AS LONG
    rtn = Fib(10)
    MSGBOX STR$(rtn)
END FUNCTION