REM "100 Doors" program for QB64 BASIC (http://www.qb64.net/), a QuickBASIC-like compiler.
REM Author: G. A. Tippery
REM Date: 12-Feb-2014
REM
REM   Unoptimized (naive) version, per specifications at http://rosettacode.org/wiki/100_doors

DEFINT A-Z
CONST N = 100
DIM door(N)

FOR stride = 1 TO N
    FOR index = stride TO N STEP stride
        LET door(index) = NOT (door(index))
    NEXT index
NEXT stride

PRINT "Open doors:"
FOR index = 1 TO N
    IF door(index) THEN PRINT index
NEXT index

END