/* Forward differences. */ /* 23 April 2010 */
differences: procedure options (main);
   declare a(10) fixed(10) static initial
      (7, 3, 9, 250, 300, 4, 68, 72, 154, 601);
   declare (i, j, m, n, t, u) fixed binary;

   m = hbound(a,1);
   get (n); if n > m then signal error;
   put skip edit (a) (F(7));
   do i = 1 to n;
      t = a(i);
      do j = i+1 to m;
         u = a(j);
         a(j) = a(j) - t;
         t = u;
      end;
      put skip edit (a) (F(7));
   end;
   put skip edit ((a(i) do i = n+1 to m)) (F(9));

end differences;