How can I write a function in C++ that would create a folder/subfolder on the hard-disk?
Standard C or C++ don't define such a function. However, most platforms (Win32, Unix) provide the function mkdir() for this purpose. Consult your compiler's online help for the exact specification of this function, as its signature varies among platforms. On Unix, for instance, mkdir() takes two parameters whereas on Win32 it takes only one.