摘要：
对这两个概念比较模糊 于是找了些资料 了解这两个用法的区别参考 http://stackoverflow.com/questions/322597/class-vs-import如果你看到这样的警告：warning: receiver 'myCoolClass' is a forward class and corresponding @interface may not exist你需要导入 #import文件 但你可以在.m实现文件中导入，并且在你的头文件中使用@class。通常情况下 #import文件是必须的 @class文件不能代替它 ，@class只移动有用的信息. 阅读全文
摘要：
转：http://stackoverflow.com/questions/9262535/explanation-of-strong-and-weak-storage-in-ios5觉得讲的很容易理解 The difference is that an object will be deallocated as soon as there are nostrongpointers to it. Even if weak pointers point to it, once the last strong pointer is gone, the object will be deallocat 阅读全文