C/C++ NaN constant (literal)?

Question

Is this possible to assign a NaN to a double or float in C/C++? Like in JavaScript you do: a = NaN. So later you can chec

Answer 1

yes, by the concept of pointer you can do it like this for an int variable:

int *a;
int b=0;
a=NULL; // or a=&b; for giving the value of b to a
if(a==NULL) 
  printf("NULL");
else
  printf(*a);

it is very simple and straitforward. it worked for me in Arduino IDE.