IOS memory release Principle

1. Keep the Count of objects created by allocation or replication 1
2. Assume that the object obtained by any other method is counted as 1 and is in the Auto Release pool. To use this object outside the current execution range, you must keep it
3. It is maintained when an object is added to the set, and is released when the object is removed from the set. Releasing the set object will release all objects in the set.
4. Make sure that the number of alloc, copy, mutablecopy, or retain messages is the same as the number of release or autorelease messages that are sent to this object. In other words, make sure that yourCodeBalance
5. Set the attribute in the access method and keep it before releasing (ztime: @ propperty and @ synthesize commands automatically create this code)
6. The nsstring object created with the @ "..." structure is a constant. Sending release or retain has no effect.