Digital Mars C++
Digital Mars C++ is a free C++ compiler for DOS and Windows.
Digital Mars C++ is an implementation of C++.
Other implementations of C++.
Originally a C compiler created by Datalight, it was sold to Zortech, who then added a C++ compiler, calling the result Zortech C++. Symantec purchased Zortech specifically to get ownership of these compilers, which were eventually acquired by Digital Mars (which is more well-known for creating the D programming language).
For more information, see Digital Mars' website.