How to display NaN in Java?

Question

In Java, I am dividing by zero, which obviously does not produce a number.

public class tempmain {
    public static void main(String args[])
    {
        float a=3/0;
        System.out.println(a);
    }
}

I expect the output to be "NaN", but it shows the following error:

Exception in thread "main" java.lang.ArithmeticException: / by zero
    at tempmain.main(tempmain.java:6)

Is there any way (apart from if(denominator==0)) by which NaN can be displayed?

Answer 1

You are getting the unexpected ArithmeticException because of the way that your numeric literals 3 and 0 are treated. They are interpreted as integers, despite the fact that you assign a to be a float. Java will interpret 3 as an integer, 3f as a float and 3.0 or 3d as a double. The division is performed as integer division and the result cast to a float. To see another interesting other effect of this - try float a = 1/3 and inspect a - you will find it is 0.0, rather than 0.3333.... as you might expect.

To get rid of the Exception - change

float a = 3/0;

for

float a = 3f/0;

As others have noted in comments and answers, if you then print a, you will see Infinity rather than NaN. If you really want to print NaN in this case, you can test a for being infinite i.e.

if (Float.isInfinite(a)) {
     System.out.println("I want to print Infinity as NaN");
}

but I'd recommend against it as highly misleading - but I suspect that's not what you meant anyway