تابع ‎isnan()‎‎ در ‎C++‎

/* isnan example */
#include <stdio.h>/* printf */
#include <math.h>/* isnan, sqrt */

int main()
{
printf ("isnan(0.0): %dn",isnan(0.0));
printf ("isnan(1.0/0.0): %dn",isnan(1.0/0.0));
printf ("isnan(-1.0/0.0): %dn",isnan(-1.0/0.0));
printf ("isnan(sqrt(-1.0)): %dn",isnan(sqrt(-1.0)));
return 0;
}