Your teacher didn't know what unresolved externals were? That's not a good sign. Typically, an unresolved external means that you're code calls a function that's declared somewhere, but never implemented. An example:


/* main.c */

int do_stuff(void);

int main(int argc, char ** argv)
{
    return do_stuff();
};


This will not compile because do_stuff() is never implemented. This usually happens because you're including a header and using functions defined in that header, but not linking in the objects created when compiling that header's corresponding C++ file.

If you look at your code, you declare all the functions giving you problems, but you didn't actually implement those functions. That is, you didn't write the functions, you just gave them names.


Take care,

Nik
http://www.bigaction.org/