[ITK] Compiling problem

[Constantinus Spanakis]

Hello, i copied a pre-existing class of itk in a different location
(outside the itk folder), in order to create a new class. Then i tried
to run a preexisting example, where i replaced the original class with
the copy that lies in a different folder. But i get the same error in
Microsoft Visual studio

Error: identifier <itkOnePlusOneEvolutionaryOptimizer2>> is undefined.

where itkOnePlusOneEvolutionaryOptimizer2 is the copied class. I keep
the main file and the copy in the same folder and the make file
contains the following instructions

project(test)

find_package(ITK REQUIRED)

include(${ITK_USE_FILE})

add_executable(test2 test2.cxx itkOnePlusOneEvolutionaryOptimizer2.cxx
itkOnePlusOneEvolutionaryOptimizer2.h)

target_link_libraries(test2 ${ITK_LIBRARIES})

What could be the problem?