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POHow can I prevent myself from accidentally using an NSNumber's pointer when I want its intValue?
 

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  1. POHow can I prevent myself from accidentally using an NSNumber's pointer when I want its intValue?
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    <p>One feature of Java that I really like is autoboxing, in which the compiler automatically converts between primitives and their wrapper classes.</p> <p>I'm writing a Core Data application in Objective-C/Cocoa, and I'm finding it frustrating to deal with my integer attributes programmatically. Here's why:</p> <pre><code>//img is a managed object that I have fetched NSString* filename = [NSString stringWithFormat:@"image%d.png", [[img valueForKey:@"imageID"] intValue]]; </code></pre> <p>If I happen to forget the <code>intValue</code> message, which I sometimes do, then the int that gets passed to <code>stringWithFormat:</code> is actually the pointer value.</p> <p>The problem is that this happens totally silently--no compiler error or warning. Sometimes I'll spend way too long debugging when this silly, stupid thing is the problem.</p> <p>Is there a way to change my programming style or my compiler settings to prevent me from getting caught in that trap?</p> <p><strong>Edit</strong>: I wasn't clear about the fact that the above example is just one of many places where I run into trouble. Here's another hypothetical example that doesn't have to do with strings:</p> <p>Entity <code>CollegeClass</code> has two integer attributes: <code>courseNumber</code> and <code>enrollmentLimit</code>. Let's say I want to compare course numbers:</p> <pre><code>//classFoo is a NSManagedObjects I've fetched if ([[classFoo valueForKey@"courseNumber"] intValue] &lt; 400) { NSLog(@"undergraduate class"); } </code></pre> <p>Or similarly, suppose I want to compute the average enrollment limit for all the classes in the CS department.</p>
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