return [NSString stringWithFormat:@"<%@: %p>", self.class, self];
return [NSString stringWithFormat:@"<%@: %p> {answer: %@, icon: %@, title: %@, options: %@}", self.class, self, self.answer, self.icon, self.title, self.options];
原文：http://www.cnblogs.com/penger/p/4412780.html