"Include what you use" means this: for every symbol (type, function, variable, or macro) that you use in foo.cc (or foo.cpp), either foo.cc or foo.h should include a .h file that exports the ...
There are different types of medicines and delivery devices to treat COPD. A nebulizer is a device that turns the liquid medicine into a mist which is then inhaled through a mouthpiece or a mask.