Several C ++ compilers (original cfront, Comeau C ++) use C as an intermediate language at compile time. Most C ++ compilers use other intermediate languages (e.g. llvm).
Edit: Since there seem to be some misunderstandings in the story: “C with classes” began with the use of the “Cpre” preprocessor. At that time it was considered strictly as a dialect of the C language, and not as a separate language in itself. In December 1983, people began to consider it as a separate language, and the name C ++ was invented. As it turned out, the development of cfront began in April 1983, so the version available for use became available (for a few select ones) at about the same time that the name "C ++" entered. This seems to be basically a coincidence.
Regarding the output of C as output, this was fairly common on Unix. For example, the Berkeley Pascal compiler and at least a couple of Fortran compilers also returned C as output.
Cpre Cfront . C , Cpre - . C , . , , , C Cpre.
Cfront, , , ( ), C. C , CFront , ..
, 2 " " C++ "C " ( , ).