Which one is better alloc init or new

Question

I am confused in this can you tell me which one is better and why?

I read somewhere that this both are used for allocing and initializing. somebody was telling me that you cant do like newWithString and all other things like that but when I tried in Xcode then Its not giving me error

      NSString *AddEmail  =[[NSString alloc]initWithString:@"Add Email"];

      NSString *AddEmail  =[NSString new];

do both will work In same way?

thank you in advance

http://stackoverflow.com/questions/3330963/alloc-init-and-new-in-objective-c — Lithu T.V, Apr 25 '13 at 06:34
Is this on a new project you created? There is no method newWithString in the iOS SDK... — Avi Tsadok, Apr 25 '13 at 06:35
then why not showing red error? you try in your Xcode wont show error — Prakash Desai, Apr 25 '13 at 06:36
@PrakashDesai Obviously __newWithString__ shows error. There is no such method — Anil Varghese, Apr 25 '13 at 06:40
Ok i got the answer my xcode is not working properly need to update it :) — Prakash Desai, Apr 25 '13 at 06:40

score 3 · Accepted Answer · edited Apr 25 '13 at 07:26

3

[[SomeClass alloc] init] will give the same result as [SomeClass new]. new is implemented as

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

The newWithString method you use gives a quite explicit warning : "Class method +newWithString not found", so even if you code compile, it will fail on this line. (Unless you declared a category on NSString).

I tend to prefer [[alloc] init], because you can allocate an object then choose how you will initialize its variables, according to the init method you chose..

edited Apr 25 '13 at 07:26

Regexident

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answered Apr 25 '13 at 06:41

Michaël Azevedo

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Yes i got it my xcode has some problem not showing me error but compile time error – Prakash Desai Apr 25 '13 at 06:43

score 1 · Answer 2 · answered Apr 25 '13 at 08:26

+[NSString new] simply returns an empty, immutable string.

It is equivalent to [[NSString alloc] init].

Your examples are not the same. If I were to correctly guess your intention, NSString * AddEmail = @"Add Email"; would be all you would need to write. You do not need to use +alloc, -initWithString:, +stringWithString:, etc. in this example because @"Add Email" is already an NSString.

[[TYPE alloc] init] and [TYPE new] are equivalent (unless overridden). Which you choose is your preference. I prefer [TYPE new] because it is shorter and there is no need to separate (or pronounce) the alloc/init message chain whenever you create a 'new' object.

Which one is better alloc init or new

2 Answers2