Adding to an existing value in Erlang

Question

I am attempting to create a function that stores a number into a record and then adds value X to that number every time the function runs.

Value: 5
Run Function          


        

Answer 1

-record(adder, {value = 5}).

add(Value) ->
    add(#adder{}, Value).

add(#adder{value =V} = Adder, Value) ->
    Adder#adder{value = V + Value}.

test() ->
  R1 = add(1),
  io:format("~p~n", [R1]),
  R2 = add(R1, 10),
  io:format("~p~n", [R2]).

Here is the output of running test:test().

6> c(test).
{ok,test}
7> test:test().
{adder,6}
{adder,16}
ok