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Goal c "Did you forget to lay out alloc and init?"

I'm just starting to climb the Objective-C learning curve (using the Nerd Ranch iOS programming book).

Based on what I know from other languages ​​about the "nesting" of several executions on the same line, I assumed that I could change:

NSString* descriptionString = [[NSString alloc] initWithFormat:@"%@", possesionName]

with a two-line version:

NSString* descriptionString = [NSString alloc];
[descriptionString initWithFormat:@"%@", possesionName]

but it seems that the second attempt throws an exception

2012-01-22 18:25:09.753 RandomPossessions[4183:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -length only defined for abstract class.  Define -[NSPlaceholderString length]!'

Can someone help me understand what exactly I am doing wrong here? Thank you very much in advance.

PS. If this is the way of reporting Objective-C, and you have to do alloc and init on the same line, just let me know - I suggested that this is just a set of functions that can either be executed two at a time, or one after the other.

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( ) , initWithFormat descriptionString, alloc .

NSString* descriptionString = [NSString alloc];
descriptionString = [descriptionString initWithFormat:@"%@", possesionName]

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Apple, initWithFormat:

NSString, Unicode .

, :

NSString* descriptionString = [NSString alloc];
descriptionString = [descriptionString initWithFormat:@"%@", possesionName];

For more information, go to: https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html#//apple_ref/occ/instm/NSString/ initWithFormat :

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