If you want to port C++ into ASM you should use the Borland C++ compiler. It has an option called "compile via assembly" (commandline switch "-B"). This first translates the CPP file to ASM and then passes it to TASM32.

If you rename TASM32.EXE to something else you will get an error message, but BCC32 won't delete the ASM file so you can take the code you want out of it.