Objective-c using @property and memory management

推荐:

NSString用copy,

delegate用assign（且一定要用assign），

非objc数据类型，比如int，float等基本数据类型用assign（默认就是assign），

而其它objc类型，比如NSArray，NSDate用retain

1.构建时即设定autorelease
2.优先autorelease而非retain
3.以声明时的顺序dealloc处理实例变量
4.避免抛出异常

1. Always declare @properties for your object instance variables
2. Always use self when accessing a property
3. Make sure all newly-created objects are autoreleased
4. Never call retain on anything
5. Never call release on anything (except in dealloc)