You could use a tool like ctags to produce a tags file containing this class information.
EDIT: I just checked this ctags.exe command line inside the Zeus editor and it seems to do what you require:
ctags.exe --C++-kinds=+c-d-e-f-g-l-m-M-n-p-s-t-T-u-v-x-X-V somefile.cpp
This command line excludes all but the class information from the tag output, so running this command against a c++ file will result in a tags text file that contains nothing but the class information from that file.
For example, here is contents of the tags file for one of the Zeus header files:
!_TAG_FILE_FORMAT 2 /extended format; --format=1 will not append ;" to lines/
!_TAG_FILE_SORTED 1 /0=unsorted, 1=sorted, 2=foldcase/
!_TAG_PROGRAM_AUTHOR Darren Hiebert /[email protected]/
!_TAG_PROGRAM_NAME Exuberant Ctags //
!_TAG_PROGRAM_URL http://ctags.sourceforge.net /official site/
!_TAG_PROGRAM_VERSION 5.7 //
ZeusRebar c:\projects\zeus3.96\zfwbar01.hpp /^class ZeusRebar : public xRebar$/;" c
ZeusToolBar c:\projects\zeus3.96\zfwbar01.hpp /^class ZeusToolBar : public xToolBar$/;" c
ZeusToolPanel c:\projects\zeus3.96\zfwbar01.hpp /^class ZeusToolPanel : public ZeusRebar$/;" c