The difference between new and Alloc Init

Background notes,new is more old-fashioned, and later found only one newallocinit This notation, reserved new One is backwards compatible, and two is often a simpler way of writing. In fact, the new is called internally by the allocinit.  

Source code:

+New { ? ? IDNewObject = (*_alloc) ((Class) Self,0);//Application Space? ? Class Metaclass= self->Isa;?? Class Metaclass= self->Isa;??return[NewObject init];??//Initialize? ?Else? ? ? ?returnNewObject;} +alloc {??return(*_zonealloc) (Class) Self,0, Malloc_default_zone ()); }? -init {??returnSelf ;?} 

[ClassName New] is basically equivalent to [[ClassName alloc] init]. The difference is only in the memory of the alloc allocated when the zone is used, what is this zone? When allocating memory to an object, the associated object is assigned to an adjacent Memory area, so that it can be used at a very low cost and improves program processing speed .

What's to separate alloc from Init?  

1. Multiple init methods can be used

2. Show call is better than implicit call

If you do not need to use the other INIT functions, such as initwithstring, just use [NSObject alloc] init] , then the new method is more convenient

* New doesn ' t support custom initializers (like initwithstring) * Alloc-init are more explicit than new

The difference between new and Alloc init