Instance variable 'variable' accessed in class method error

Question

I have a variable declared in the header file :

@interface

int _nPerfectSlides;

and

@property (nonatomic, readwri         


        

Answer 1

An instance variable is, as its name suggests, only accessible in the instance methods (those declared with -). Class methods (declared with +) have no access to instance variable, no more than they have access to the self object.