Oc--arc use

ARC's judging criteria; If no strong pointer points to the object, the object is freed

1.ARC Features
1> does not allow calls to release, retain, Retaincount
2> allows rewriting of dealloc, but does not allow calls to [super Dealloc]
Parameters of the 3> @property
*strong: Strong pointer for member variable (for OC object type)
*weak: Weak pointer for member variable (for OC object type)
*assign: For non-OC object types
4> former retain changed to strong

-fno-objc-arc turn into non-arc
-f-objc-arc turn into Arc

When both ends are circular references, the solution:

1>arc
One end with strong, the other end with weak
2> Non-Arc
One end with retain, the other end with assign



The hands are divided into 2 types:
1. Strong pointer: By default, all pointers are strong pointers _strong
2. Weak pointer: _weak

Oc--arc use