What are the differences between the c++ file extensions? [duplicate]

This question already has an answer here:

• .c vs .cc vs. .cpp vs .hpp vs .h vs .cxx [duplicate] 6 answers

I'd like to know what the differences are between all of the C++ source file extensions. There are .cc, .cpp, .cxx, and .c++. Why are there so many different extensions? Are there any advantages to using one over the other?