non-ARC 的Objective-C 要点

1. 程序中使用@property的地方就创建了一个对应的instance variable
2. 如一个class如person是retain的，则

• //viewDidLoad 中设置
  self.person = [Person alloc] initWithArray:sbs]
  //这里这样会造成内存泄漏，因为person是retain的，它在setter里面（既[self setPerson]）已经计数为1了。这里面又新初始化了（alloc）一个新的，所以目前self对person的引用计数为2了。怎么办呢?
  个人认为哦，只好在创建的时候多加一个autorelease，因为最后self拥有person是通过setter方法，所以要在alloc后面加一个自动释放。修改后如下：
  
  self.person =[[Person alloc] initWithArray:sbs]autorelease];
  

  3. 行规是在“在init/dealloc中不适用setter/getter”　

自己可能以后会做cocos2D，

所以property在cocos2D中的规则，高手总结，原文地址http://www.raywenderlich.com/2712/using-properties-in-objective-c-tutorial

So to avoid making unnecessary properties for everything, here’s what I like to use for Cocos2D:

1. Don’t use properties at all.
2. Set instance variables directly to your created sprites, etc.
3. Since they’ll be children of the current layer, Cocos2D will keep the retain count up as long as they’re there.
4. When you remove the object from the layer, set the instance variable to nil.

I just personally find it simpler and faster to develop this way.

Note this strategy doesn’t work if you want to keep track of an object not currently in the layer – you’ll have to use an alternative strategy there.