let main () =
  let n= 100 and x= ref 0.4 and r= ref 3.0  and z= ref 0. and dr= 0.0001 in
  let t = open_out "bifurc.don" in
    print_string "Dessin des bifurcations de x_(n+1) = r*x_n * (1-x_n)";
    print_newline ();
    let f x = !r*.x*.(1.-.x) in
      for j=1 to 10000 do
	for i=0 to n do
	  begin
	    z:=!x;
	    x:=f !z;
	    if i>50 then Printf.fprintf t "%f %f\n" !r !x;
	  end
	done;
	r:=!r+.dr;
      done;
      close_out t;;

main();;