byte casting

[Kedar Dravid]

How is it that System.out.println((byte)128)
gives -128 as output?
128 is beyond the range of byte, so calcualtion will proceed as 128%256.
But what about the -ve sign?

[sanjeevmehra mehra]

byte 8 bit
max value it can hold " 0 1 1 1 1 1 1 1 "

8th bit is sign bit & value is +127

128 default data type is int (32 bytes)
128 ==> "0 0 0 0 0 0 0 0 - 0 0 0 0 0 0 0 0 - 0 0 0 0 0 0 0 0 - 1 0 0 0 0 0 0 0"

cast it(32 bits) to byte(8 bits) i.e pick 8 bits from right side i.e
1 0 0 0 0 0 0 0

Please convert this value to decimal value.


I am not in touch with this (shift operator & conversions), pls. wait for better response.
[ November 27, 2004: Message edited by: sanjeevmehra mehra ]