How to import a library with extension .h to a project C on Xcode
How to import a library with extension .h to a project C on Xcode
I am not sure what "project C" means, but to include a Class (for example "TheClassToAdd") in an Xcode project you copy the .h and .m file into the folder in the left column in Xcode and you add this line before the @interface in the .m file or the .h file from which you wish to reference methods in the Class:
#import "TheClassToAdd.h"