About unsigned right shift operator

[SreedharRao Rao]

Hello ranchers,

It seems that 128>>>2 results in 32. Could you please explain me how do we calculate this?

Mnay thanks,
Sreedhar

[Cheryl Gray]

I used this formula #/2^n where # is the number and n is the shift number, so we get 128/2^2 = 128/4 = 32. Since the # is not a negative number, the sign will not change, giving you a positive result.

[Javier Sanchez Cerrillo]

... 128 64 32 16 8 4 2 1

0 ... 1 0 0 0 0 0 0 0

"sign bit" .... more bits

32 bits long --------------->

If you displace the previous number with >>> the unsigned right shift operator you move the 1 two places which result in 32.

Remember the >> "normal" right shift operator does not displace the leftmost bit (sign bit).
[ February 15, 2007: Message edited by: Javier Sanchez Cerrillo ]

[Remko Strating]

In Java integers are stored as a 32-bit integer which is binary like a lot of zeros from which the last part of 128 is like.

1000 0000 which is 2^7 = 128.

You're using a unsigned right shift operator so al the bytes are moved 2 place to the right which means

0010 0000 which is 2^5 = 32.

When you use the right shift operator (>> the sign bit will be the same. This means a negative number will stay negative. Using the unsigned right shift operator a negative number will be positive because the sign bit will also be replaced with a zero. In your example the orginal value was positive so using the signed or the unsigned operator has no influence.