aspose file tools*
The moose likes Programmer Certification (SCJP/OCPJP) and the fly likes use of calculator in exam 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 "use of calculator in exam" Watch "use of calculator in exam" New topic
Author

use of calculator in exam

kundan varma
Ranch Hand

Joined: Mar 08, 2004
Posts: 322
HI all
Can we use calculator in exam from binary to decimal conversions
Thanks
candy


SCJP1.4,SCBCD,SCEA,CNA
Failures are practice shoots for success.
Kurankyi Dadson
Greenhorn

Joined: Mar 12, 2004
Posts: 14
No, afraid not.
Bert Bates
author
Sheriff

Joined: Oct 14, 2002
Posts: 8883
    
    5
candy -
It wouldn't even help if you could! You have to understand two's complement, and if you do you won't need to calculate big old binary numbers.


Spot false dilemmas now, ask me how!
(If you're not on the edge, you're taking up too much room.)
kundan varma
Ranch Hand

Joined: Mar 08, 2004
Posts: 322
Hi Bert
In ur operator and assignment self test, u r saying 2>>5 is 0 but it should be 2/64=0.03125 as per ur formula.Plz clarify.
Also is there any formula for >>> operator.
Thanks
candy
kundan varma
Ranch Hand

Joined: Mar 08, 2004
Posts: 322
HI Bert
If you can throw some light on this, then i will be highly obliged.
Waiting for ur reply
THanks
candy
Lasse Koskela
author
Sheriff

Joined: Jan 23, 2002
Posts: 11962
    
    5
Originally posted by candy varma:
In ur operator and assignment self test, u r saying 2>>5 is 0 but it should be 2/64=0.03125 as per ur formula.

I'm not sure about which formula are we talking about, but here's an explanation:
2 in decimal is 00000010 in binary
Each >> shift "moves" the bits to the right, which leads to
"2 >> 1" = 0000001
"2 >> 2" = 0000000
"2 >> 3" = 0000000
"2 >> 4" = 0000000
etc.
The ">>>" operator works the same way except that when the most significant (sign) bit is moved to the right, the "vacant slots" are filled with zeroes. With ">>" those vacant slots are filled with whatever the sign bit was.


Author of Test Driven (2007) and Effective Unit Testing (2013) [Blog] [HowToAskQuestionsOnJavaRanch]
Bert Bates
author
Sheriff

Joined: Oct 14, 2002
Posts: 8883
    
    5
candy -
It seems to me Lasse's explanation is a great start - do you understand his answer? It seems that your formula for dividing by 2 to the N isn't really the best way to think about this topic - you really have to look at the binary.
kundan varma
Ranch Hand

Joined: Mar 08, 2004
Posts: 322
THanks Lasse and bert for your inputs.
I will sit in this month end for the exam.
THanks again
candy
Jeroen Wenting
Ranch Hand

Joined: Oct 12, 2000
Posts: 5093
Originally posted by Bert Bates:
candy -
It seems to me Lasse's explanation is a great start - do you understand his answer? It seems that your formula for dividing by 2 to the N isn't really the best way to think about this topic - you really have to look at the binary.

bit shifting operations are integer operations, not floating point.
Therefore if you take a floating point division to determine the answer you will need to take into consideration as the result ONLY the integer part of the resulting floating point number.
And even then you have to consider that the result is invalid when you're doing a bitshift operation on a negative number.
Examples (using 8 bit ints for brevity).
-1 >> 1 == 10000001 >> 1 == 01000000
-1 >>> 1 == 10000001 >>> 1 == 11000000
Neither of which is equal to -1/2 == -0.5 (the int part of which is -0 )


42
Lawrence Hom
Greenhorn

Joined: Apr 09, 2004
Posts: 1
Hello Jeroen,
I am looking at your shift operation example.
Do you have the results flipped?
Should the results be:
-1 >> 1 == 10000001 >> 1 == 11000000
-1 >>> 1 == 10000001 >>> 1 == 01000000
Cheers, Lawrence
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: use of calculator in exam