How to increment a NSNumber

Question

How do I increment a NSNumber?

i.e. myNSNumber++

Answer 1

If you're using it to store an integral value:

myNSNumber = @(myNSNumber.longLongValue + 1);

For floating point stuff the short answer is the following, but it's a bad idea to do this, you'll loose precision and if you're doing any kind of comparison later like [myNSNumber isEqual:@(4.5)] you might be surprised:

myNSNumber = @(myNSNumber.floatValue + 1);

If you need to do math on floating point numbers represented as objects in Objective-C (i.e. if you need to put them in arrays, dictionaries, etc.) you should use NSDecimalNumber.

Answer 2

Use a category to ease future use. Here is a basic idea.

 - (void)incrementIntBy:(int)ammount {
      self = [NSNumber numberWithInt:(self.intValue + ammount)];
 }

Answer 3

NSNumber objects are immutable; the best you can do is to grab the primitive value, increment it then wrap the result in its own NSNumber object:

NSNumber *bNumber = [NSNumber numberWithInt:[aNumber intValue] + 1];