undefined reference to `ExampleRosClass::ExampleRosClass(ros::NodeHandle*)'

[ibrahimqazi]

Hello sir,
I am studying the section "using_a_ros_library", when I compile my package it gives me this error:

CMakeFiles/ros_class_test_node.dir/src/example_ros_class_test_main.cpp.o: In function `main':
example_ros_class_test_main.cpp:(.text+0x256): undefined reference to `ExampleRosClass::ExampleRosClass(ros::NodeHandle*)'
collect2: error: ld returned 1 exit status
using_a_ros_library/CMakeFiles/ros_class_test_node.dir/build.make:112: recipe for target '/home/ibrrahim/catkin_workspaces/learning_ros_ws/devel/lib/using_a_ros_library/ros_class_test_node' failed
make[2]: *** [/home/ibrrahim/catkin_workspaces/learning_ros_ws/devel/lib/using_a_ros_library/ros_class_test_node] Error 1
CMakeFiles/Makefile2:3035: recipe for target 'using_a_ros_library/CMakeFiles/ros_class_test_node.dir/all' failed
make[1]: *** [using_a_ros_library/CMakeFiles/ros_class_test_node.dir/all] Error 2
Makefile:140: recipe for target 'all' failed

My CMakeLists.txt file contents are:

cmake_minimum_required(VERSION 3.0.2)
project(using_a_ros_library)

find_package(catkin REQUIRED COMPONENTS
  creating_a_ros_library
  roscpp
  std_msgs
  std_srvs
)



catkin_package(
  # INCLUDE_DIRS include
  LIBRARIES example_ros_library
  CATKIN_DEPENDS creating_a_ros_library roscpp std_msgs std_srvs
  #DEPENDS system_lib
)

###########
## Build ##
###########


include_directories(
  #include
  ${catkin_INCLUDE_DIRS}
  ${creating_a_ros_library}
)


add_executable(ros_class_test_node src/example_ros_class_test_main.cpp)


target_link_libraries(ros_class_test_node ${catkin_LIBRARIES})

Please note that I am not using catkin simple package. Any advice will be highly appreciated.
Thank you