摘要:
By default, a readwrite property will be backed by an instance variable, which will again be synthesized automatically by the compiler. An instance va 阅读全文
摘要:
/* 子类可以重写父类中的方法,甚至是root class中的方法,比如NSObeject 的new方法,但是后提示警告如下 Method is expected to return an instance of its class type 'Student', but is declared to return 'void' */ #import @interface Studen... 阅读全文