End Google Ads 201810 - BS.net 01 --> Hi
I am a new comer in C++. I have an MFC application that using some header files and libraries. I set the 'additional library directories' and 'additional include directories' in project settings. But whenever I want to make an instance of one of those classes I get this error:

error C2259: cannot instantiate abstract class due to the following members: ....

It is wierd as it works in another project same as this one, and there are some other classes in the lib files as this class, but the error doesn't occur in those conditions.

I know the concept of abstract class. Please help me in advanse.
Thanks