restructure + lecutre 07

lectures/05/_build/echo.ml

@@ -0,0 +1,6 @@
+let () =
+  let len = Array.length Sys.argv - 1 in
+  for i = 1 to len do
+    Printf.printf (if i <> len then "%s " else "%s\n") Sys.argv.(i)
+  done;;
+