/*==============( Binary search )================*/
BiSearch: Procedure Expose stem.
Parse Arg value /* Search value */

found = 0 /* Index of the found Item */
bottom = 1 /* Index of the first Item */
top = stem.0 /* Index of the last Item */

Do While found = 0 & top >= bottom
  mean = (bottom + top) % 2
  If value == stem.mean Then found = mean
  Else If value < stem.mean Then top = mean - 1
  Else bottom = mean + 1
End

Return found
/*** End BiSearch ***/