About executable files

edit

I'm the new one to ROS.. I have written two cpp file named talker.cpp and listener.cpp in src and i add two lines seeing below in CMakeLists.txt file

rosbuild_add_executable(talker src/talker.cpp)
rosbuild_add_executable(listener src/listener.cpp)

now when i give a command $make it displays

make: *** No targets specified and no makefile found.  Stop.

Would you please explain me clearly the steps which we need to execute cpp files in ROS environment please explain it me in steps