please i'm new users of ros and i don't understand this probleme can you help me

edit

-- +++ processing catkin package: 'chapter2_tutorials'
-- ==> add_subdirectory(chapter2_tutorials)
-- Configuring done
CMake Error at chapter2_tutorials/CMakeLists.txt:189 (add_executable):
  Cannot find source file:

    src/example1_b.cpp

  Tried extensions .c .C .c++ .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp
  .hxx .in .txx


-- Build files have been written to: /home/home/dev/catkin_ws/build
make: *** [cmake_check_build_system] Erreur 1
Invoking "make cmake_check_build_system" failed