Question

How to check if floating point is NaN in C

Answer 1

#include <math.h>
#include <stdio.h>

int main() {
    double n = 0.0 / 0.0; // Produces NaN
    
    if (isnan(n)) {
        printf("n is NaN\n");
    } else {
        printf("n is not NaN\n");
    }
    
    return 0;
}



/*
run:

n is NaN

*/

 

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Answer 2

#include <math.h>
#include <stdio.h>

int main() {
    double n = 0.0 / 0.0; // Produces NaN
    
    if (n != n) {
        printf("n is NaN\n");
    } else {
        printf("n is not NaN\n");
    }
    
    return 0;
}



/*
run:

n is NaN

*/

 

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