If I split the code into .h and .cpp files, which of the following keywords used in the header must also be used in the .cpp file and which must not go into the .cpp file:

const, virtual, override, noexcept, constexpression

and in which order do they have to be used, i.e. is the following order correct:

virtual constexpression int foo() const override noexcept;

Please feel free to give a rule if such exists.