Added example answers for chapters 13 and 14 to fix #1

CH_14_multithreading_and_multiprocessing/exercise_01/solution_00.py

@@ -0,0 +1,40 @@
+# See if you can make an echo server and client as separate
+# processes. Even though we did not cover
+# `multiprocessing.Pipe()`, I trust you can work with it
+# regardless. It can be created through
+# `a, b = multiprocessing.Pipe()` and you can use it with
+# `a.send()` or `b.send()` and `a.recv()` or `b.recv()`.
+import multiprocessing
+
+
+def echo_client(receive_pipe, send_pipe, message):
+    print('client sending', message)
+    send_pipe.send(message)
+    print('client received', receive_pipe.recv())
+
+
+def echo_server(receive_pipe, send_pipe):
+    while True:
+        message = receive_pipe.recv()
+        print('server received', message)
+        send_pipe.send(message)
+
+
+if __name__ == '__main__':
+    a, b = multiprocessing.Pipe()
+    server = multiprocessing.Process(
+        target=echo_server,
+        args=(a, b),
+    )
+    server.start()
+
+    for i in range(5):
+        client = multiprocessing.Process(
+            target=echo_client,
+            args=(a, b, f'message {i}'),
+        )
+        client.start()
+        client.join()
+
+    server.terminate()
+    server.join()