Objective-c method without return type

Question

Is it correct to write objective-c method like this

-methodA: (NSString *)str // without return type 
{
    return @"test";
}

Above method is working fine for me.
Is -methodA: (NSString *)str same as -(id)methodA: (NSString *)str?
I am using Mac 10.5 os x sdk.

Answer 1

To answer your question, from "The Objective-C 2.0 Programming Language":

If a return or argument type isn’t explicitly declared, it’s assumed to be the default type for methods and messages — an id.

So - methodA:(NSString *)str is valid and the same as - (id)methodA:(NSString *)str.

However having said that it is certainly unusual coding practice and not to be encouraged - type the extra four characters!

Answer 2

- (void) methodA (NSString *)str //always start a methodod name lower case
{
  return;  //If you do not return anything then there is nothing to return. 
}

(id) is different from (void). You will have to return somthing here. id represents an object of any type. Only void represents 'nothing'.

Answer 3

It is allowed, as language specification states

If a return or parameter type isn’t explicitly declared, it’s assumed to be the default type for methods and messages—an id.

Answer 4

I changed -init in my app:

-init
{
    ...
    return self;
}

and compiler did not show any warning, and if I change -init like that:

-(int)init
{
    ...
    return 0;
}

compiler shows warning about expected type, so I could say -init and -(id)init are the same methods, since I did not even know that compiler would pass this syntax and since checking language's features like that is bad practice :). I will read Apple's docs about Objective-C and try to find out something about that. Thanks for nice question :)

EDIT:

wow, you can read docs here, chapter Class Interface. (void), (NSObject*) and etc are only casts. Quote: "Method return types are declared using the standard C syntax for casting one type to another". And another quote: "If a return or parameter type isn’t explicitly declared, it’s assumed to be the default type for methods and messages—an id".