Question

code in xcode 4.2

Game Model.h

#import <Foundation/Foundation.h>

@interface Game_Model : NSObject{
    NSString  *playerName;
    int play;
    int won;
}

@property (nonatomic,retain) NSString *playerName;
@property (nonatomic,readonly,assign) int play;
@property (nonatomic,readonly,assign) int won;
@end

Game Model.m

#import "Game Model.h"

@implementation Game_Model
@synthesize playerName,play,won;

+(NSString *)description{
    return [NSString stringWithFormat:@"%@. Player:%@. Score: %d/%d",[super description],self.playerName,self.won,self.play];
}
@end

I made exactly (or nearly exactly) as in a book, but I got error messages:

• implicit conversion of an Objective-C pointer to ‘struct objc_class
  *’ is disallowed with ARC
• member reference type ‘struct objc_class *’ is a pointer; maybe you meant to use ‘->’?
• incomplete definition of type ‘struct objc_class’ Automatic Reference Counting Issue:
• Implicit conversion of an Objective-C pointer to ‘struct objc_class
  *’ is disallowed with ARC
  I simply have no idea about these errors!
  Please help me!

Answer 1

description is not a class method, but an instance method. What you create is a class method: +(NSString*)description;. You should not try to access instance properties (ivars) in a class method. Change + into -. Good luck!