`isNan` in Objective-C

Question

Is there a function like isNan (Javascript example) for Objective-C?

I just noticed this code is causing to display Nan %, so I need to detect is a value is NAN so I could change it to 0.

[portefeuillePercentWaarde setText:[NSString stringWithFormat:@"%.2f%%", verschilPrencentage]];

Voted to close as duplicate. The good news is that the other question has your answer :) http://stackoverflow.com/questions/719417/determine-if-nsnumber-is-nan — e.James, Jan 21 '10 at 12:54
@e.James: not a duplicate: your link is for NSNumber, this question is for float/double. — Cœur, Oct 12 '16 at 05:57
Objective-C for float or double: `isnan(verschilPrencentage)`; Swift for floatingPointType: `verschilPrencentage.isNaN`. — Cœur, Oct 12 '16 at 06:19

score 22 · Accepted Answer · answered Jan 21 '10 at 12:55

Try just adding

#include <math.h>

and then using the standard isnan() function to test.

You can also use the "trick" that NaN is not equal to anything, including itself:

double x;

// do some operation here
x = doSomething();
if (x != x)
  printf("%g is probably NaN, it's not equal to itself\n", x);

1 Answers1