Can C++ be used to write programming languages?
I know that C can be used to write other languages, but can C++ do it
too?
C++ is nearly a strict superset of C. Therefore anything one can do in C can
be done in C++. (There are some minor incompatibilities but they are not
relevent as they have no impact on capability, and C99 has some features not
included in C++, but they are merely convenience features, and have no real
impact on language capability.
However, a programming language is an abstract thing. One does not really
write a programming language. Language documentation or specifications can
be written, but one would not usually use C++ for that. C++ can be used to
write compilers and interpreters for programing languages.