wip

2 files changed, 31 insertions, 0 deletions

diff --git a/step-04/README.md b/step-04/README.md
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/step-04/README.md
diff --git a/step-04/tut17.erl b/step-04/tut17.erl
new file mode 100644
index 0000000..6808340
--- /dev/null
+++ b/step-04/tut17.erl
@@ -0,0 +1,31 @@
+-module(tut17).
+
+-export([start_ping/1, start_pong/0,  ping/2, pong/0]).
+
+ping(0, Pong_Node) ->
+    {pong, Pong_Node} ! finished,
+    io:format("ping finished~n", []);
+
+ping(N, Pong_Node) ->
+    {pong, Pong_Node} ! {ping, self()},
+    receive
+        pong ->
+            io:format("Ping received pong~n", [])
+    end,
+    ping(N - 1, Pong_Node).
+
+pong() ->
+    receive
+        finished ->
+            io:format("Pong finished~n", []);
+        {ping, Ping_PID} ->
+            io:format("Pong received ping~n", []),
+            Ping_PID ! pong,
+            pong()
+    end.
+
+start_pong() ->
+    register(pong, spawn(tut17, pong, [])).
+
+start_ping(Pong_Node) ->
+    spawn(tut17, ping, [3, Pong_Node]).