C <math.h> - isnan()
The C <math.h> isnan() macro returns true if the given argument is a NaN (Not-A-Number) value, else returns false. A NaN value is used to identify undefined or non-representable values for floating-point elements, for example - the result of 0/0.
Syntax
isnan(x)
Parameters
x |
Specify a floating-point value. |
Return Value
Returns true (non-zero value) if the argument is an infinity value, else returns false (zero value).
Example:
The example below shows the usage of isnan() macro.
#include <stdio.h>
#include <math.h>
int main (){
printf("isnan(10.5): %d\n", isnan(10.5));
printf("isnan(1.0/0.0): %d\n", isnan(1.0/0.0));
printf("isnan(0.0/0.0): %d\n", isnan(0.0/0.0));
printf("isnan(sqrt(-1.0)): %d\n", isnan(sqrt(-1.0)));
return 0;
}
The output of the above code will be:
isnan(10.5): 0 isnan(1.0/0.0): 0 isnan(0.0/0.0): 1 isnan(sqrt(-1.0)): 1
❮ C <math.h> Library
