This week's book giveaway is in the OO, Patterns, UML and Refactoring forum.
We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line!
See this thread for details.
The moose likes Programmer Certification (SCJP/OCPJP) and the fly likes Confusion   Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

JavaRanch » Java Forums » Certification » Programmer Certification (SCJP/OCPJP)
Bookmark "Confusion   " Watch "Confusion   " New topic


Priya Jotwani
Ranch Hand

Joined: Oct 30, 2002
Posts: 53
When I try to print the value of z, it gives 64 as result .Can anyone plz tell why ??
byte x=64;
byte y=5;
byte z= (byte)(x*y);
Bhushan Jawle
Ranch Hand

Joined: Nov 22, 2001
Posts: 249
Ideally with proper data type you should get 320 as answer but as it exceeds the capacity of a byte most significant bits (MSB) in binary representation is chopped of . Amount decimal reprn. of remaining bits is 64.
i.e. 101000000 is 320 but if you try to fit that in byte first 10 is chopped of so you get 1000000 which is 64 in dec.
Vijayakumar Arya
Ranch Hand

Joined: Jan 27, 2003
Posts: 76
64 is getting printed correctly. Let me explain how,
z = 64 * 5 = 320 == 0x140
You are doing a type conversion (narrowing) on z, this drops the higher order bytes and takes only upto the bytes specified for the datatype,
byte - 1 byte
short - 2 bytes
int - 4 bytes
(byte)0x140 = 0x40 = 64 in decimal, so 64 is getting printed.

Thanks,<p>Vijay<p>The Hand that gives, Gathers.
Priya Jotwani
Ranch Hand

Joined: Oct 30, 2002
Posts: 53
Thanx Bhushan!!
wood burning stoves
subject: Confusion
It's not a secret anymore!