function search( key : typekey; var r : dataarray ) : integer;
     var j : integer;

     begin
     if n > 1 then
          begin
          {*** initial probe location ***}
          j := trunc( (key-r[1].k) / (r[n].k-r[1].k) * (n-1) ) + 1;
          if key < r[j].k then
                    while (j>1) and (key<r[j].k) do j := j-1
               else while (j<n) and (key>r[j].k) do j := j+1
          end
     else j := 1;

     if r[j].k = key then search := j    {*** found(r[j]) ***}
                     else search := -1;  {*** notfound(key) ***}
     end;