Wednesday, February 8, 2012

create an Object and NIL value


I am used to have this in my code



myClass.h 





@property ( strong, nonatomic ) ClassA *varA


myClass.m 





varA  = [[ClassA alloc] init];

if ( varA isEqual:nil )

   NSLog@"var A is nil");

else

   NSLog@"var A is not nil");


this is a result from console 





var A is not nil


I thought var A should be nil then. So my question is what does blue line do and why var A is not nil after all

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2 comments:

  1. UserFebruary 8, 2012 at 6:23 PM

    You just allocated varA, then you have a ClassA object, you didn't release it or setting it to nil, so why did you expect it to be nil?

    It's normal behaviour, it's like you just made (alloc) yourself a nice cup of coffee, if you didn't drink/throw (release or setting it to nil) your coffee should still be there, right?

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  2. UserFebruary 8, 2012 at 6:23 PM

    So, nope the nil value is gone right after you allocate the object in a memory space, also you set the values of the ivars to something in the calling for the init method in which you probably call a [super init]; or something similar so you can get the features of the father object.

    Hopefully this answers your question.

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