I'm going to assume that your professor wants you to use Turbo C++ 2.01, as it's free and considered "antique." However, Turbo C++ 3.0 and 3.1 are not free and still considered commercial software requiring a license.
Borland's C++ compiler version 5.5 couldn't be described as "ancient". It is fairly up-to-date with C/C++ standards. GCC is a popular compiler but has a number of non-standard extensions.