Question

I am just wondering if there is any way to create the same function with different count of parameters? Something like this:

sum_of_n(Num)->
    sum_of_n(Num, 0);
sum_of_n(0, Accum)->
    Accum;
sum_of_n(Num, Accum) ->
    sum_of_n(Num - 1, Accum + Num).

As I see Erlang doesn’t allow to create the function with one and two parameters the same time. Is there a good way to create such function or I need use two different functions?

Answer 1

You can have two different functions with the same name, but different number of arguments:

sum_of_n(Num)->
    sum_of_n(Num, 0). %% Note the period

sum_of_n(0, Accum)->
    Accum;
sum_of_n(Num, Accum) ->
    sum_of_n(Num - 1, Accum + Num).

In export, fun, etc. you can refer to them as FunName/NumberOfArgs, e.g.

-export([sum_of_n/1]).