From 7fb5559c7853a8fbd7f75df73105ba49c36c319e Mon Sep 17 00:00:00 2001
From: ricmaps <ricardomapurungajunior@gmail.com>
Date: Mon, 15 Jun 2026 23:51:33 -0300
Subject: [PATCH] Add Rot13 in Elixir

---
 archive/e/elixir/rot13.ex | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 archive/e/elixir/rot13.ex

diff --git a/archive/e/elixir/rot13.ex b/archive/e/elixir/rot13.ex
new file mode 100644
index 000000000..91fa874c9
--- /dev/null
+++ b/archive/e/elixir/rot13.ex
@@ -0,0 +1,16 @@
+defmodule Rot13 do
+  @doc """
+  Returns a string after applying the Rot-13 cypher
+  """
+  @spec rot13(str :: String.t()) :: String.t()
+  def rot13(str), do: to_charlist(str) |> Enum.map(&rot/1) |> to_string()
+
+  defp rot(char) when char in ?a..?z, do: rem(char - ?a + 13, 26) + ?a
+  defp rot(char) when char in ?A..?Z, do: rem(char - ?A + 13, 26) + ?A
+  defp rot(char), do: char
+end
+
+case System.argv() do
+  [str] when byte_size(str) > 0 -> Rot13.rot13(str) |> IO.puts()
+  _ -> IO.puts("Usage: please provide a string to encrypt")
+end