This is just a simple package mainly based on beginner_tutorials of ROS Wiki Tutorial. This can be used as a minimal package for testing some implementations.

1. Add this package into your workspace, and run catkin_make
2. Open 3 terminals and run these for C++ publisher and subscriber examples, remember to source your workspace's setup.bash first:

   $ roscore 

   $ rosrun demo_pkg demo_talker 

   $ rosrun demo_pkg demo_listener 

3. Open 3 terminals and run these for Python publisher and subscriber examples, remember to source your workspace's setup.bash first:

   $ roscore 

   $ rosrun demo_pkg talker.py 

   $ rosrun demo_pkg listener.py 

4. Open 3 terminals and run these for C++ service client examples, remember to source your workspace's setup.bash first:

   $ roscore 

   $ rosrun demo_pkg demo_add_two_ints_server 

   $ rosrun demo_pkg demo_add_two_ints_client 2 5 

5. Open 3 terminals and run these for Python service client examples, remember to source your workspace's setup.bash first:

   $ roscore 

   $ rosrun demo_pkg add_two_ints_server.py 

   $ rosrun demo_pkg add_two_ints_client.py 2 5 

6. Open 3 terminals and run these to ensure the io_listener.py is working, remember to source your workspace's setup.bash first:

   $ roscore 

   $ rosrun demo_pkg io_listener.py 

   $ rostopic list | grep /io/