Bitwise Operators. Khalid Mughal.

[Pankaja Shinde]

Bitwise Operators. Khalid Mughal.

class bitwiseOperators
{
public static void main(String[] args)
{
char v1 = ')';// Unicode value 41
int result1 = ~v1;
System.out.println(" ~v1 = " + result1);
}
}

Output is :

~ v1 = -42

Can anyone explain me above output in detail.
Code is from Khalid Mughal (jdk 1.4) page 76
In detail I mean, what is value of v1 in binary, then what is its complement binary value, then what is its decimal value, etc. I know how to convert decimal to binary and vice versa.
When I am doing this program on PC I am getting correct answer. But when I am trying on piece of paper I got 22 as answer.

Pankaj Shinde

[marc weber]

First, note that bit manipulations are included on the 1.4 exam, but not on the 1.5 exam.

41 in binary is: 0000 0000 0000 0000 0000 0000 0010 1001
So ~41 is:       1111 1111 1111 1111 1111 1111 1101 0110

We know this represents a negative value, because the lead bit (the "sign bit") is 1. So to determine the value, we invert the bits, then add 1. Inverting the bits just brings us back to what we started with...

0000 0000 0000 0000 0000 0000 0010 1001

Then adding 1 gives us...

0000 0000 0000 0000 0000 0000 0010 1010

...which is 42. So the value is -42.
[ April 12, 2007: Message edited by: marc weber ]

[Pankaja Shinde]

thank you sir