Cfront was the original compiler for C++ (then known as "C with Classes") from around 1983, which converted C++ to C; developed by Bjarne Stroustrup at AT&T Bell Labs. The preprocessor did not understand all of the language and much of the code was written via translations. Cfront had a complete parser, built symbol tables, and built a tree for each class, function, etc. Cfront was based on CPre, a C compiler started in 1979.