CODEWITHSUNDEEP
objective-cios
kschins
kschins

Reputation: 1224

NSNumber limit?

What is the highest int that NSNumber allows? I've seen the answer elsewhere on these forums hence why I'm deeply confused here.

int miles = 35000;
vehicle.mileage = [NSNumber numberWithInt:miles];
NSLog(@"int value = %d", miles);
NSLog(@"mileage = %@", vehicle.mileage);

The output is:

int value = 35000
mileage = -30536

I must be missing some terrible easy here, but can someone explain to me why this is not working correctly?

UPDATE: After looking further, vehicle.mileage is getting set correctly to 35000 but when I display this via NSLog(@"%@", vehicle.mileage) it is outputting it incorrectly. I have yet to find the "magic" value when this stops working because as of now, it works for values up to ~30,000.

Upvotes: 1

Views: 2542

Answers (4)

sunkehappy
sunkehappy

Reputation: 9091

Overview

NSNumber is a subclass of NSValue that offers a value as any C scalar (numeric) type. It defines a set of methods specifically for setting and accessing the value as a signed or unsigned char, short int, int, long int, long long int, float, or double or as a BOOL. (Note that number objects do not necessarily preserve the type they are created with.) It also defines a compare: method to determine the ordering of two NSNumber objects.

So NSNumber is as big as what it wraps. For your unexpected result you can check comment bellow your qestion from @sjs.

Upvotes: 1

MCKapur
MCKapur

Reputation: 9157

The limit NSNumber integer can have is known as INT_MAXbut 35, 000 is nowhere close to that. The problem must be with vehicle object or the mileage property in the vehicle, either of them may be nil

So, go ahead and log with this conditional statement:

if (!vehicle) {
 NSLog(@"Vehicle is nil");
}
else if (!vehicle.mileage) {
 NSLog(@"Vehicle's mileage is nil");
}

Tell me your result

Upvotes: 0

bneely
bneely

Reputation: 9093

+numberWithInt: interprets the value as signed int. Mileage would never be negative, so I suggest using [NSNumber numberWithUnsignedInt:]

Upvotes: 0

Ramy Al Zuhouri
Ramy Al Zuhouri

Reputation: 21966

NSNumber is just a wrapper so it goes in overflow when the wrapped primitive type goes in overflow.
So if you use numberWithInt the maximum number allowed is INT_MAX (defined in limits.h), if you use a numberWithFloat the maximum number allowed is FLOAT_MAX, and so on.
So in this case you aren't going in overflow, I doubt that INT_MAX would be so low.

Upvotes: 3

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