How to produce a NaN float in c?

Question

float f = (float)\'a\';
if(f < 0){ 
}   
else if(f == 0){ 
}   
else if(f > 0){ 
}   
else{
    printf(\"NaN\\n\");                                                     


        

Answer 1

Following C program will produce a NaN. The second statement will result in a NaN.

#include 
#include 
#include "math.h"

int _tmain(int argc, _TCHAR* argv[])
{
    double dSQRTValue = sqrt( -1.00 ); 
    double dResult = -dSQRTValue;  // This statement will result in a NaN.
    printf( "\n %lf", dResult );

    return 0;
}

Following will be the output of the program.

1.#QNAN0