Objective c min max operation

Question

Can you explain me why this code:

NSInteger i = -1;
NSUInteger x = 1;
NSLog(@"min = %lu", MIN(i, x));
NSLog(@"max = %lu", MAX(i, x));;

prints min = 1

max = 18446744073709551615

You are comparing objects of 2 different types... MAX and MIN internally cast the values. — jberlana, Jul 07 '15 at 16:02

score 1 · Accepted Answer · answered Jul 07 '15 at 15:39

You compare two different types: signed (NSInteger) and unsigned (NSUInteger). MIN/MAX convert all to unsigned integer.

Moreover, negative NSInteger is printed with %lu instead of %du. Therefore see a big number.

NSInteger i = -1;
NSUInteger x = 1;
NSLog(@"min = %ld", MIN(i, (NSInteger)x));
NSLog(@"max = %ld", MAX(i, (NSInteger)x));

score 0 · Answer 2 · edited May 23 '17 at 11:45

0

It's because i is actually being converted into an unsigned int implicitly. See here. As a result it rolls over to 18446744073709551615.

edited May 23 '17 at 11:45

Community

answered Jul 07 '15 at 15:37

Gordonium

score 0 · Answer 3 · edited May 23 '17 at 11:45

0

It is because i is being implicitly converted to an unsigned long. It is part of the way xcode handles integer conversions. Here is a similar post. NSUInteger vs NSInteger, int vs unsigned, and similar cases

edited May 23 '17 at 11:45

Community

answered Jul 07 '15 at 15:40

3 Answers3