Cheat Sheats on Objective-C, from Programming in Objective-C, Fifth Edition
###Hello World:
###Basic Data Types(4.1):
###Methods for Working with Dynameic Types(9.1):
###Exception Handling(P412):
###NSArray class’s six initialization methods(P419):
###enum type(P441):
###Conditional Compliation(P514):
###Compound Literals(P614):
###NSNumber Creation and Retrieval Methods(15.1)
###Common NSString Methods:(15.2):
###Common NSMutableString Methods(15.3):
###Common NSArray Methods(15.4):
###Common NSMutableArray Methods(15.5):
###Some NSValue Wrapper and Unwrapper Methods(15.6):
###Common NSDictionary Methods(15.7):
###Common NSMutableDictionary Methods(15.8):
###Common NSSet Methods(15.9):
###Common NSMutableSet Methods(15.10):
###Some NSIndexSet Methods(15.11):
###Common NSFileManager File Methods(16.1):
###Common NSFileManager Directory Methods(16.2):
###Enumerating the Contents of a Directory(Program 16.4)
###Common Path Utility Methods(16.3)
###Common Path Utility Functions(16.4)
###Common iOS Directories(16.5)
###NSProcessInfo Methods（16.6）
###Common NSFileHandle Methods(16.7)
###Memory Management and Automatic Reference Counting(17)
###Archiving(19.0)