arithmetic_geometric_mean:           /* 31 August 2012 */
   procedure options (main);
   declare (a, g, t) float (18);

   a = 1; g = 1/sqrt(2.0q0);
   put skip list ('The arithmetic-geometric mean of ' || a || ' and ' || g || ':');
   do until (abs(a-g) < 1e-15*a);
      t = (a + g)/2; g = sqrt(a*g);
      a = t;
      put skip data (a, g);
   end;
   put skip list ('The result is:', a);
end arithmetic_geometric_mean;