function binsearch( array() as integer, target as integer ) as integer
    'returns the index of the target number, or -1 if it is not in the array
    dim as uinteger lo = lbound(array), hi = ubound(array), md = (lo + hi)\2
    if array(lo) = target then return lo
    if array(hi) = target then return hi
    while lo + 1 < hi
        if array(md) = target then return md
        if array(md)<target then lo = md else hi = md
        md = (lo + hi)\2
    wend
    return -1
end function