Re: NSUInteger in for-loop?
Re: NSUInteger in for-loop?
- Subject: Re: NSUInteger in for-loop?
- From: Jason Coco <email@hidden>
- Date: Mon, 15 Sep 2008 00:51:28 -0400
On Sep 15, 2008, at 00:45 , Brett Powley wrote:
On 15/09/2008, at 2:15 PM, Alex Reynolds wrote:
I'm wondering if I'm using unsigned integers (specifically
NSUInteger) properly or not.
I was under the impression that unsigned integers run from 0 to
MAX_INT, but when I use them in a "for" loop within these bounds,
the loop does not seem to always obey these constraints.
For example:
for (NSUInteger counter = 5; counter >= 0; --counter)
{
NSLog(@"NSUInteger: %d", counter);
}
keeps running well after the "counter" variable turns negative:
First problem: %d is for signed integers; if you want to see the
value, you want %u.
Second problem (which you'll see if you change the NSLog): counter
is unsigned, so it *never* "turns negative".
The values of counter in your loop will be 5,4,3,2,1,0,MAX_UINT,
MAX_UINT-1, etc
(Note that the range of values for unsigned integers is 0..MAX_UINT,
not MAX_INT.)
Just to quickly reiterate, since NSUInteger changes size based on the
architecture, it's important that you compare it to NSUIntegerMax...
Jason
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