Original Post
OGRE forward declares all its classes in the standard include: Sure, it decreases dependencies, but you don't have to do it this way. You can forward declare a class in another class's header file. This makes OGRE hard to study as it's not clear what classes depend on what. You should be able to look at a .h file of a class and see exactly what it depends on by looking at what classes are included or forward declared. But I may be wrong on my opinion. What do you think about this technique? Also, I'm curious to know other people's rule on whether you include a file or just forward declare the class. I typically include the class if I can because I like to just be able to include one file and know that I can use the class rightly. Dependency issues will force otherwise of course though.
// Pre-declare classes
// Allows use of pointers in header files without including individual .h
// so decreases dependencies between files
class Angle;
class Animation;
class AnimationState;
class AnimationStateSet;
class AnimationTrack;
class Archive;
class ArchiveFactory;
class ArchiveManager;
class AutoParamDataSource;
class AxisAlignedBox;
class AxisAlignedBoxSceneQuery;
class Billboard;
class BillboardChain;
class BillboardSet;
...
