% 
% Copyright (C) 1988 by Bobo Leffler. All rights reserved.
% This program is provided for unrestricted use, provided that this 
% copyright message is preserved. There is no warranty, and no author 
% or distributer accepts responsibility for any damage caused by this 
% program. 
%
/bubblesort {   % array => array        (sort array with bubble sort)
10 dict begin
    /a exch def
    a length 2 sub -1 -1 {                      % for j=n-2 step -1 until 0 do
        0 1 3 -1 roll {                         % for i=0 step 1 until j do
            /i exch def
            a i 1 add get a i get lt {          % if a[i+1] < a[i] then
               a i get                          % a[i]
               a i 1 add get a i 3 -1 roll put  % a[i] = a[i+1]
               a i 1 add 3 -1 roll put          % a[i+1] = a[i]
            } if
        } for
    } for
    a
end
} def