anchor.diff:  	%%Last false bit
   	io:fwrite("| ~8s          ||  ~8s  ||  ~8s  |~n",["LFB","???",bs_to_string( bs_getlast_false(Bin))]),
   	io:fwrite("| ~8s          ||  ~8s  ||  ~8.10B  |~n",["LFB indx","???",bs_getlast_false_index(Bin)]),
  +	%%Number of true bits
  +	io:fwrite("| ~8s          ||  ~8s  ||  ~8.10B  |~n",["NbTB","???",bs_count_true(Bin)]),
  +	%%number of false bits
  +	io:fwrite("| ~8s          ||  ~8s  ||  ~8.10B  |~n",["NbFB","???",bs_count_false(Bin)]),
   
   	ok.
   
  
positive.code: -export([bs_and/2,bs_or/2,bs_xor/2,bs_sl/2,bs_sr/2]).
  -export([bs_getfirst_true/1,bs_getfirst_false/1,bs_getlast_true/1,bs_getlast_false/1]).
  -export([bs_getfirst_true_index/1,bs_getfirst_false_index/1,bs_getlast_true_index/1,bs_getlast_false_index/1]).
  -export([bs_show/1,bs_autotest/1,bs_oper_boolalg_test/2,bs_oper_boolsimplif_test/3]).
  
  %%existing bitstring operators : 
  
negative.code: bs_getlast_false_index(<<B/bits>>) -> bs_getlast_true_index(bits_oper:bs_not(<<B/bits>>)).
  bs_getfirst_false_index(<<B/bits>>) -> bs_getfirst_true_index(bits_oper:bs_not(<<B/bits>>)).
  
  %TODO Test It : number of true bits, number of false bits
  bs_count_true(<<I:1/bits,B/bits>>) when I == <<0:1>> -> 0 + bs_count_true(<<B/bits>>);
  bs_count_true(<<I:1/bits,B/bits>>) when I == <<1:1>> -> 1 + bs_count_true(<<B/bits>>);
  bs_count_true(<<>>) -> 0.
  
  bs_count_false(<<I:1/bits,B/bits>>) when I == <<0:1>> -> 1 + bs_count_false(<<B/bits>>);
  bs_count_false(<<I:1/bits,B/bits>>) when I == <<1:1>> -> 0 + bs_count_false(<<B/bits>>);
  bs_count_false(<<>>) -> 0.
  
  %TODO :improve performance and code design... same with bitwise comprehension if possible ? or more arithmetic ?
  % unary bitwise not
  