scratch: Change scratch subdir example to show the use of additional files

scratch/.gitignore

@@ -1,6 +1,5 @@
 # Ignore everything on scratch by default, except the provided examples
 /*
-!.gitignore
 !subdir/
 !scratch-simulator.cc
 !CMakeLists.txt

scratch/subdir/scratch-subdir-additional-header.cc

@@ -14,16 +14,17 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include "ns3/core-module.h"
+// This file contains the implementation of the functions declared in the
+// corresponding header file.
 
-using namespace ns3;
+#include "scratch-subdir-additional-header.h"
 
-NS_LOG_COMPONENT_DEFINE ("ScratchSimulator");
+namespace ns3 {
 
-int
-main (int argc, char *argv[])
+std::string
+ScratchSubdirGetMessage ()
 {
-  NS_LOG_UNCOND ("Scratch Simulator");
-  CommandLine cmd;
-  cmd.Parse (argc, argv);
+  return "Scratch Subdir";
 }
+
+} // namespace ns3

scratch/subdir/scratch-subdir-additional-header.h

@@ -0,0 +1,32 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+// This header does not provide much functionality but is meant to demonstrate how,
+// in a scratch subdirectory, one can create new programs that are implemented
+// in multiple files and headers.
+
+#include <string>
+
+namespace ns3 {
+
+/**
+ * Get a message from the subdir.
+ *
+ * \return The message from the subdir
+ */
+std::string ScratchSubdirGetMessage ();
+
+} // namespace ns3

scratch/subdir/scratch-subdir.cc

@@ -0,0 +1,49 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+// This example shows how to create new simulations that are implemented in
+// multiple files and headers. The structure of this simulation project
+// is as follows:
+//
+// scratch/
+// |  subdir/
+// |  |  - scratch-subdir.cc                   // Main simulation file
+// |  |  - scratch-subdir-additional-header.h  // Additional header
+// |  |  - scratch-subdir-additional-header.cc // Additional header implementation
+//
+// This file contains the main() function, which calls an external function
+// defined in the "scratch-subdir-additional-header.h" header file and
+// implemented in "scratch-subdir-additional-header.cc".
+
+#include "ns3/core-module.h"
+#include "scratch-subdir-additional-header.h"
+#include <string>
+
+using namespace ns3;
+
+NS_LOG_COMPONENT_DEFINE ("ScratchSubdir");
+
+int
+main (int argc, char *argv[])
+{
+  std::string message = ScratchSubdirGetMessage ();
+  NS_LOG_UNCOND (message);
+
+  Simulator::Run ();
+  Simulator::Destroy ();
+
+  return 0;
+}