NSString stringwithstring and stringwithformat difference

Question

I am really confused any help will be highly appreciated

So what is the difference below

int myInteger = 1;
myString = [NSString stringWithFormat:@"anotesound%i",myInteger];

and this

myString = [NSString stringWithString:@"anotesound1"];

I thought both should be same but open al do not accept those are equal, it works for the stringwithstring but not works for stringwithformat

how does it not work? compiler error or crash or what does your result string look like? Have you tried myString = [NSString stringWithFormat: @"anotesound%d",myInteger]; ? — Michael Dautermann
– Michael Dautermann, Commented Nov 25, 2011 at 21:25
Those will output the same thing "anotesound1". Not sure what your question is. — ColdLogic
– ColdLogic, Commented Nov 25, 2011 at 21:26
NSLog(@"%@",myString); gives the same output that is what i am hitting my head to the wall for 2 hours. Also i try with %d not working... I have a class Sound manager and at that class on this line NSNumber *numVal = [soundLibrary objectForKey:aSoundKey]; EXC_BAD_ACCESS error occurs. Thank you for your answer — frenz
– frenz, Commented Nov 25, 2011 at 21:31

hoshi · Accepted Answer · 2011-11-26 01:40:56Z

1

stringWithFormat: always returns a newly created and autoreleased object, which will eventually be released and become a zombie. stringWithString: in this case returns the literal (constant) object itself, which will never been released.

I'd recommend you to learn the memory management of iOS, or use ARC. http://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/MemoryMgmt/

answered Nov 26, 2011 at 1:40

hoshi

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Comments

zaph · Accepted Answer · 2011-11-25 21:28:31Z

0

The results are the same, the error is elsewhere.

The difference is in wether or not myInteger is a constant or fill change on different instantiations. If it is always the same just use:

myString = @"anotesound1";

There is no need for the stringWithString method when the string is a constant.

answered Nov 25, 2011 at 21:28

zaph

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4 Comments

frenz Over a year ago

Thank you anyway still not figure it out.

frenz Over a year ago

string is not constant, it is changed by a switch 1 or 2

zaph Over a year ago

Run the Analyzer and turn on NSZombies. The difference in code it just changing timings enough to cause the bug to appear.

frenz Over a year ago

Thank you so much it found a zombie. An Objective-C message was sent to a deallocated object (zombie) at address: 0xf37d820. Now what should i do?

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