Errors in paragraph before the code, two thirds down page says:

To complete the application you can add the implementation of the DoDataExachange() function for
the CCustomerView class to CustomerView.cpp:

(Errors: DoDataExachange and second CustomerView.cpp)
It should say:

To complete the application you can add the implementation of the DoDataExchange() function for
the CCustomerView class to MainFrm.cpp: