The issue wasn't with the code itself, but the compiler being used. I don't have the best explanation, but according to the advice that I received from @gregspears:

"Borland C++ 5.x is available for free on various places on the web. This is a full 32-bit version . . . which is pretty much a TurboC that can run in today's MS Windows. Essentially, if your TurboC code works in this later version but not 16 bit TurboC, then this fact may also point to a problem other than your code. You might also find it easier to spend most of your development time in current Windows and this newer version of Borland C++, and then only do a final compile and deploy in 16-bit TurboC for your finished product. ymmv."