global function quick_select(sequence s, integer k)
integer left = 1, right = length(s), pos
object pivotv, tmp

    while left<right do
        pivotv = s[k];
--      {s[k], s[right]} = {s[right], s[k]}
        tmp = s[k]
        s[k] = s[right]
        s[right]=tmp
        pos = left
        for i=left to right do
            if s[i]<pivotv then
--              {s[i], s[pos]} = {s[pos], s[i]}
                tmp = s[i]
                s[i] = s[pos]
                s[pos]=tmp
                pos += 1
            end if
        end for
--      {s[right], s[pos]} = {s[pos], s[right]}
        tmp = s[right]
        s[right] = s[pos]
        s[pos]=tmp
        if pos==k then exit end if
        if pos<k then
            left = pos + 1
        else
            right = pos - 1
        end if
    end while
    return {s,s[k]}
end function

sequence s = {9, 8, 7, 6, 5, 0, 1, 2, 3, 4}
integer r
for i=1 to 10 do
    {s,r} = quick_select(s,i)
    printf(1," %d",r)
end for
{} = wait_key()