alloc, init, and new in Objective-C [duplicate]

Question

One book for about iPhone programming instantiates classes like this:

[[Class alloc] init] 

Another book about Objective-C does it like this:

[Class new] 

What's the difference?

Answer 1

+new is implemented quite literally as:

+ (id) new {     return [[self alloc] init]; } 

Nothing more, nothing less. Classes might override it, but that is highly atypical in favor of doing something like +fooWithBar:.