7L7W, erlang, day2.

my.erl

-module(my).

-export([wordnum/1]).
-export([count_to_10/0]).
-export([value_at/2]).
-export([checkout/1]).

wordnum([]) -> 0;
wordnum(W) -> [_|Tail] = W, wordnum(Tail) + 1.

count_to_10() ->
  Count_to = fun(_, Limit, Limit) ->  io:fwrite("~p~n", [Limit]);
    (F, Limit, 0) -> io:fwrite("~p~n", [0]), F(F, Limit, 1);
    (F, Limit, Current) -> io:fwrite("~p~n", [Current]), F(F, Limit, Current + 1)
  end,
  Count_to(Count_to, 10, 0).

value_at(_, []) -> "not found";
value_at(Val, List) ->
  [{K, V}|Rest] = List,
  case K of
    Val -> V;
    _ -> value_at(Val, Rest)
  end.


checkout([]) -> [];
checkout(List) ->
  [{Item, Quantity, Price}|Rest] = List,
  [{Item, Quantity*Price}|checkout(Rest)].