Cocoa-Touch. What is the semantic difference between class method init versions alloc/init?

Question

Could someone please clarify for me the semantic difference between these two:

self.foo = [NSMutableDictionary dictionaryWithCapacity:theCapacity];

self.foo = [[[NSMutableDictionary alloc] initWithCapacity:theCapacity] autorelease];

Are the interchangable? If not how exactly do they differ.

Thanks in advance.

Cheers, Doug

Answer 1

In this case they are totally interchangeable.

dictionaryWithCapacity:theCapacity is just a shortcut