Object-c Study (ix)--alloc\retain\release

Alloc is used to create objects, when created, the reference count is 1 and can only be called once;

Retain makes a reference count of +1, which can be called multiple times;

Release makes the reference count-1, which can be used more than once.

Note: When the reference count is 0 o'clock, the object is destroyed by the system from memory, and the Dealloc method of the object is called automatically before it is destroyed.

Golden rule: If you use Alloc,[mutable]copy,retain for an object, you must release it using the corresponding release or autorelease.

Object-c Study (ix)--alloc\retain\release