int mynumber = 25;
^--- global means it exists once, in c++ the equiv is 'static', which means
the same except 'global object scope' (OOP)
To inline code is to take something too small to be worth its own function
and COPY it during the compile/creation of your code - like a macro..
How would a global be a macro?
This is somewhat the logic behind the semantics.
For further info see: Dranith++