Math function doubt

[Vidyavathi saravanan]

public class Test1{ 
 public static void main (String args[])
{
float f4 = -5.5f; 
float f5 = 5.5f; 
float f6 = -5.49f; 
float f7 = 5.49f; 
System.out.println("Round f4 is " + Math.round(f4)); 
System.out.println("Round f5 is " + Math.round(f5)); 
System.out.println("Round f6 is " + Math.round(f6)); 
System.out.println("Round f7 is " + Math.round(f7)); 
} 
}

Answer is given as -5,6,-5,5.
My doubt is the 3 rd output.
Math.round(-5.49f)--- how come this is -5. As per my understanding it is -6.
Could anyone please explain this. Its confusing me a lot.


Thanks.

[Nina Binde]

float f6 = -5.49f;

round always rounds a float or a double to the nearest integer or a long respectively. If it is right in the middle like 5.5, it rounds to the nearest large integer.
For the above example, -5.49 is closer to -5 than it is to -6. Hence , the output.

The answer would be -6 if f6 = -5.51f.

Get it?

[Jay Pawar]

Vidyavathi,
If you look the underlying implementation of round , it is nothing but adding 0.5f to the number and then perform floor on the result. In your case,

        Math.round(-5.49f); will be 
        Math.floor(-5.49+0.5);
        Math.floor(-4.99) = -5.0
        int of 5.0 will be 5

I know this round function is confusing sometimes, but if you know floor method correctly then you will never fail in getting answer for round function. Hope this helps ya.
[ November 11, 2004: Message edited by: Jay Pawar ]