example.erl

-module(example).

-export([words_count/1]).

words_count(Str) ->
  words_count_ac(Str, outside,  0).

words_count_ac([], _, Acc) ->
  Acc;
words_count_ac([Head | Tail], outside, Acc) when Head /= 32 ->
  words_count_ac(Tail, inside, Acc + 1);
words_count_ac([Head | Tail], inside, Acc) when Head == 32 ->
  words_count_ac(Tail, outside, Acc);
words_count_ac([_ | Tail], States, Acc) ->
  words_count_ac(Tail, States, Acc).