1defmodule Concat do
2 def join(a, b, sep \\ "")
3
4 def join(a, b, _sep) when b == "" do
5 a
6 end
7
8 def join(a, b, sep) do
9 a <> sep <> b
10 end
11end
12
13IO.puts(Concat.join("Hello", ""))
14IO.puts(Concat.join("Hello", "world", "-"))
15IO.puts(is_atom(String))
besaid.zone