What's the difference between [NSNull null] and nil?

Question

Here\'s a context where I have seen that:

NSMutableArray *controllers = [[NSMutableArray alloc] init];
for (unsigned i = 0; i < kNumberOfPages; i++) {
            


        

Answer 1

You cannot add a nil value to an NSArray or NSMutableArray. If you need to store a nil value, you need to use the NSNull wrapper class, as shown in that snippet you have. This is specified in the documentation.