Math Class min max ?

[Jay Pawar]

Hi,
Can someone explain me the behavior of the code below ?

public class Test {
public static void main (String[] args){
       System.out.println("Answer max : " +Math.max(Float.NaN, Float.POSITIVE_INFINITY));
       System.out.println("Answer min : " +Math.min(Float.NaN, Float.POSITIVE_INFINITY));
}
}

Answer max : NaN
Answer min : NaN

Why is the output in both cases: NaN ?

TIA
[ November 09, 2004: Message edited by: Jay Pawar ]

[Joe Borderi]

public static float max(float a, float b)

Returns the greater of two float values. That is, the result is the argument closer to positive infinity. If the arguments have the same value, the result is that same value. If either value is NaN, then the result is NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. If one argument is positive zero and the other negative zero, the result is positive zero.

[Jay Pawar]

Borderi,
I tried the following code. I am still confused...

class Test1234 {
public static void main (String args[]) {
 
if (Float.NaN > Float.POSITIVE_INFINITY) {
System.out.println("Float.NaN is greater");
}
else {
System.out.println("Float.POSITIVE_INFINITY is greater");
}
 
}
}

The output is Float.POSITIVE_INFINITY is greater

I am wondering about the underlying implementation of Math.max function

[Joyce Lee]

Hi Jay,

I am wondering about the underlying implementation of Math.max function
You can find the source code (src.zip) for the Java APIs under your jdk directory.

Joyce

[Joe Borderi]

Jay,

That's an interesting code snippet. In American English we have a saying: "that's like comparing apples to oranges." If you are unfamiliar with it, the idiom translates to "trying to compare two incomparable things."

I modified your code experiment. Try running this:

class Test1234 {
  public static void main(String args[]) {
 
    if (Float.NaN > Float.POSITIVE_INFINITY) {
      System.out.println("Float.NaN is greater");
    }
    else {
      System.out.println("Float.POSITIVE_INFINITY is greater");
    }    
    
    if (Float.POSITIVE_INFINITY > Float.NaN) {
      System.out.println("Float.POSITIVE_INFINITY is greater");
    }
    else {
      System.out.println("Float.NaN is greater");
    }
  }
}

When you think about it, the result is consistent with the general rule of comparing anything to NaN.