473,789 Members | 2,478 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

sbyte understanding needed

Hello i'm just starting out with csharp.

and am trying to figure out why an sbyte can take any value from '-128'
to 128.

i've drawn a BIT box with eight bytes, and I'm assuming the eighth bit
is used to SIGN the number, which leaves seven bits.

when all 7 bits are on you get : 127
so i was assuming the most you can get negative would be 127, and the
eighth bit would be used to sign the fact that the number was
negative...

where does the extra one to make -128 come from?

If i've totally misunderstood the handling of this variable in the
computers memory.. please advise.

thanks,

Gary.

Jan 25 '06 #1
6 1848
-128 to 127 i mean.. sorry.

Jan 25 '06 #2
ga********@mywa y.com wrote:
Hello i'm just starting out with csharp.

and am trying to figure out why an sbyte can take any value from '-128'
to 128.

i've drawn a BIT box with eight bytes, and I'm assuming the eighth bit
is used to SIGN the number, which leaves seven bits.

when all 7 bits are on you get : 127
so i was assuming the most you can get negative would be 127, and the
eighth bit would be used to sign the fact that the number was
negative...

where does the extra one to make -128 come from?

If i've totally misunderstood the handling of this variable in the
computers memory.. please advise.


sbyte is stored as a two's complement number. See
http://en.wikipedia.or g/wiki/Two's_complemen t
for more information.

Jon

Jan 25 '06 #3
http://en.wikipedia.org/wiki/2%27s_complement_notation

<ga********@myw ay.com> wrote in message
news:11******** **************@ o13g2000cwo.goo glegroups.com.. .
Hello i'm just starting out with csharp.

and am trying to figure out why an sbyte can take any value from '-128'
to 128.

i've drawn a BIT box with eight bytes, and I'm assuming the eighth bit
is used to SIGN the number, which leaves seven bits.

when all 7 bits are on you get : 127
so i was assuming the most you can get negative would be 127, and the
eighth bit would be used to sign the fact that the number was
negative...

where does the extra one to make -128 come from?

If i've totally misunderstood the handling of this variable in the
computers memory.. please advise.

thanks,

Gary.

Jan 25 '06 #4
A byte can have 256 distinct values. In this case (I assume) the high order
bit is used as the sign. Therefore positive values are 0x0000 - 0x7fff and
negative values are 0x8000 - 0xffff (or perhap more appropriately 0xffff
(-1) to 0x8000 (-128)). The key here is that 0 is considered a postive
value since the sign bit is not set.

<ga********@myw ay.com> wrote in message
news:11******** **************@ g44g2000cwa.goo glegroups.com.. .
-128 to 127 i mean.. sorry.

Jan 25 '06 #5
For anyone else seeking the answer to the question I asked - I think
i've managed to find the answer by following the links the people in
this group kindly contributed.

Please - if anyone is reading this, can you confirm or refute what i'm
about to say!

The reason the highest negative number has a magnitude greater by 1,
than the highest positive number is as follows.

When all seven bits are off including the most significant bit (which
is used to denote the sign of the number) the number is read as zero
(i.e. the sign is positive, and the number is 0 )
BUT.. when the most significant bit is on and all the other bits are
off, this number is taken as the highest negative number available, as
(-0 doesn't make sense) - so in this case its -128, which is why the
maximum negative number has a magnitude greater than the highest
positive number by one.

=)

Jan 25 '06 #6
ga********@mywa y.com wrote:
For anyone else seeking the answer to the question I asked - I think
i've managed to find the answer by following the links the people in
this group kindly contributed.

Please - if anyone is reading this, can you confirm or refute what i'm
about to say!

The reason the highest negative number has a magnitude greater by 1,
than the highest positive number is as follows.

When all seven bits are off including the most significant bit (which
is used to denote the sign of the number) the number is read as zero
(i.e. the sign is positive, and the number is 0 )
BUT.. when the most significant bit is on and all the other bits are
off, this number is taken as the highest negative number available, as
(-0 doesn't make sense) - so in this case its -128, which is why the
maximum negative number has a magnitude greater than the highest
positive number by one.

=)


I read the wiki article just like you and I started to think of it this way:

positive numbers are like this:
00000000 = 0
00000001 = 1
00000010 = 2 and so on. That is, they go "up" from zero, countingwise.

negative numbers do the same thing (but with the signbit on), but
instead of the number "origin" at zero, it's at -128:
10000000 = -128
10000001 = -127 etc...

at least that's my take on it at any rate.

Scott
Jan 25 '06 #7

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

2
3716
by: Nick | last post by:
Hi, Problem statement: Calling a java method from Dot Net code that returns a java byte array. Overview: I have a java server from which I need to establish connection. I hva ebeen able to send across data to the server in a serialised stream. However, when I need to geta response back to the client (.Net), I get a binary stream. What I wanna do is to convert this stream into an SByte array (The java byte is actually a signed byte,...
3
1312
by: Stephen Gennard | last post by:
Hello, I having a problem dynamically invoking a static method that takes a reference to a SByte*. If I do it directly it works just fine. Anyone any ideas why? I have include a example below... --
3
2202
by: Steve - DND | last post by:
After downloading and using two different memory profiling applications today, it seems that sbyte, int16, and int32 are all stored using 12b of memory. Someone please tell me I'm reading these memory profilers wrong! If I'm really reading it correctly, then what's the point of using anything other than a 32 bit integer? If they're all going to be stored the same way, then I can't achieve any memory savings(which I was really hoping for) by...
2
24907
by: Ray Ackley | last post by:
I need to convert a byte to an sbyte - and it has to preserve the original binary meaning of the 8 bits. For example - a 1111 1111, which is interpreted as byte to be 255, should show up in the sbyte as -1. The BitConverter class only takes 2 byte arrays or larger, and the Convert.ToSByte simply throws an overflow error. Any ideas? Thanks, Ray Ackley
1
12554
by: Darrel | last post by:
I am using binary writer to write an array of bytes to disk. However, my data starts out as an array of sbytes. I am currently type casting each array element in a for loop. Is there a faster method for converting an array of sbytes to an array of bytes? Thanks, Darrel
5
8518
by: Pat Ireland | last post by:
I am attempting to pass an SByte to another .NET class that expects the data to be passed as SByte *. I searched around and found the boxing can be used to produce a pointer but I'm not sure if this is appropriate. I am using the following sequence: // Load class Assembly c = Assembl.LoadFrom("filename ....); // Get the types cTypes = c.GetTypes();
3
6407
by: reju | last post by:
I have to convert an sByte array to byte array. This sbyte array contains some signed values due to this .net converting functions will throw an exception.any work around for this? is there any way to pass sbyte array to stream classes eg: memory stream?
0
1396
by: Ben Voigt [C++ MVP] | last post by:
Chip Gore wrote: Actually, because you are using the C++/CLI compiler, microsoft.public.dotnet.languages.vc is the most appropriate place to discuss this. To be useful from C# and other .NET languages, the member functions of your ref class should accept parameters of type System::String^. The C++/CLI compiler provides some pretty simple methods for getting the data as native C++ characters if you need to, for example the...
2
1379
by: K Viltersten | last post by:
I try the following. sbyte HalvOfFour () { sbyte b = 4; return b / 2; } Apparently, since 2 is regarded as int, the operation upgrades my b to and int and after it has been performed, i stand there with an int, which is wrong
0
9663
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
10195
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
0
9979
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
9016
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
1
7525
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
6765
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5415
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
5548
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4090
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.