let print_student_latex_in_table (hpr:string -> unit) (stu:student) =
let max_columns = 10 in
hpr (Printf.sprintf "\\rule[-3mm]{0pt}{8mm} %s ~ & %s ~ " stu.name stu.pren);
for i = 1 to max_columns do hpr " & "; done;
hpr "\\\\ \\hline \n"