octomap simple_example.cpp compilation error

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After success in building 3d maps i am trying to play with them for example: to detect tables in the 3d map. So trying to run the sample program. In the documentation it is said simple.cpp is an example but i could not find it neither in ros-octomap nor standalone octomap. But i found simple_example.cpp in standalone octomap folder which seems to be the updated file of simple.cpp.

But i am unable to compile it. Am i missing something ??