Integer.Min_value

[amit taneja]

hii
in one of the dan explaination to question...there is written that


If the argument is a negative integral value, then the returned value is the two's complement of the argument. The magnitude of Integer.MIN_VALUE is one greater than the magnitude of Integer.MAX_VALUE; therefore, the absolute value of Integer.MIN_VALUE exceeds the range of Integer.MAX_VALUE. Due to the limited range of type int, the two's complement of Integer.MIN_VALUE is Integer.MIN_VALUE. For that reason, the Math.abs method returns Integer.MIN_VALUE when the argument is Integer.MIN_VALUE. The negation of Short.MIN_VALUE is well within the range of type int; so Short.MIN_VALUE is never returned by the Math.abs method.


i m not able to understand fully what does that means...
if anybody pls explain me with eg. would be gr8 help to me...

[marc weber]

The range of an int is -2^31 to (2^31)-1, which is -2147483648 to 2147483647. Note that the magnitude of the negative bound is one greater than that of the positive bound.

So the absolute value of Integer.MIN_VALUE is actually greater than Integer.MAX_VALUE. In particular, we might expect the absolute value to be [phone], but this is one greater than what can be expressed as a positive int, so this overflows to Integer.MIN_VALUE.

In terms of twos complement, flipping the bits of Integer.MIN_VALUE results in Integer.MAX_VALUE, then adding 1 causes the overflow. Note the output from the code below...

class AbsNeg {
  public static void main(String[] args) {
    int max = Integer.MAX_VALUE;
    int min = Integer.MIN_VALUE;
 
    System.out.println("MAXIMUM...");
    System.out.println(" int: " + max);
    System.out.println(" binary: " + Integer.toBinaryString(max));
 
    System.out.println("\nMINIMUM...");
    System.out.println(" int: " + min);
    System.out.println(" binary: " + Integer.toBinaryString(min));
 
    System.out.println("\nABS VALUE...");
    System.out.println(" abs max: " + Math.abs(max));
    System.out.println(" abs min: " + Math.abs(min));
 
    System.out.println("\nMAX+1...");
    System.out.println(" bin max+1: " + Integer.toBinaryString(max+1)); 
    System.out.println(" abs max+1: " + Math.abs(max+1));
  }
}

This is not a concern when a short is passed to the Math.abs(int) method, because the short is widened to type int, which can easily accomodate Short.MAX_VALUE + 1.
[ May 12, 2005: Message edited by: marc weber ]