Difference between [[NSDate date] retain] and [[NSDate alloc] init]

Question

As both of the following serves the same purpose,

today = [[NSDate date] retain];    

and

today = [[NSDate alloc] init]; 
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Answer 1

[NSDate date] is a convenience constructor using which you can leave the headache of releasing the object to autorelease pool. Sending a retain message to the convenience constructor like [[NSDate date] retain] makes you the owner of the object and you are responsible for releasing it properly.

[[NSDate alloc] init] is the default initializer by which you become the owner of the object, which is almost equal to [[NSDate date] retain].