# Binary Division Problem Help

Discussion in 'C Programming' started by jamestuck21, Nov 30, 2006.

1. ### jamestuck21Guest

Hi,

I'm trying to work out a binary division problem

1100 / 101010101010111

Here is what I have so far but I'm not sure if I'm doing it correctly
and I'm suppose to continue the division until there is only a
remainder left

110
______________________
1100 [ 101010101010111
1100
_______________
1101
1100
_______________
01010
1100
_____________
110

I'm not sure if I'm doing this correctly and I don't really have a way
of checking if I'm doing it right. Does anyone know of a simple web
calculator that I can check against my answer or if someone could run
through this example with me, that would be great. thank you

jamestuck21, Nov 30, 2006

2. ### santoshGuest

jamestuck21 wrote:
> Hi,
>
> I'm trying to work out a binary division problem

<snip>

Post to sci.math

santosh, Nov 30, 2006

3. ### Ben PfaffGuest

"jamestuck21" <> writes:

> I'm trying to work out a binary division problem
>
> 1100 / 101010101010111

The integer quotient is 0, as always when the divisor is greater
than the dividend, for positive operands. The remainder is 1100.
--
Ben Pfaff
email:
web: http://benpfaff.org

Ben Pfaff, Nov 30, 2006
4. ### Fred KleinschmidtGuest

"jamestuck21" <> wrote in message
news:...
> Hi,
>
> I'm trying to work out a binary division problem
>
> 1100 / 101010101010111
>
> Here is what I have so far but I'm not sure if I'm doing it correctly
> and I'm suppose to continue the division until there is only a
> remainder left
>
> 110
> ______________________
> 1100 [ 101010101010111
> 1100
> _______________
> 1101
> 1100
> _______________
> 01010
> 1100
> _____________
> 110
>
> I'm not sure if I'm doing this correctly and I don't really have a way
> of checking if I'm doing it right. Does anyone know of a simple web
> calculator that I can check against my answer or if someone could run
> through this example with me, that would be great. thank you
>

You have
A=1100
B=101010101010111

But your division example tries (incorrectly) to do B/A

Try a newsgroup like sci.math. But be sure you know which division you want!
--
Fred L. Kleinschmidt
Boeing Associate Technical Fellow
Technical Architect, Software Reuse Project

Fred Kleinschmidt, Nov 30, 2006
5. ### Al BalmerGuest

On 30 Nov 2006 10:27:57 -0800, "jamestuck21" <>
wrote:

> Does anyone know of a simple web
>calculator that I can check against my answer or if someone could run
>through this example with me, that would be great. thank you

Does it have to be on the web? Since you're appear to be posting from
Windows, I'd suggest the Windows calculator, in scientific mode.

11100011100

--
Al Balmer
Sun City, AZ

Al Balmer, Nov 30, 2006
6. ### jamestuck21Guest

Windows calculator does not give the correct solution.

An example that I worked out with the correct solution is not the same
as the windows calculator is giving

1001 / 101110000

Solution = 101011 with Remainder of 011 and the remainder is what I'm
interested in.

Al Balmer wrote:
> On 30 Nov 2006 10:27:57 -0800, "jamestuck21" <>
> wrote:
>
> > Does anyone know of a simple web
> >calculator that I can check against my answer or if someone could run
> >through this example with me, that would be great. thank you

>
> Does it have to be on the web? Since you're appear to be posting from
> Windows, I'd suggest the Windows calculator, in scientific mode.
>
> 11100011100
>
> --
> Al Balmer
> Sun City, AZ

jamestuck21, Dec 1, 2006
7. ### Ben PfaffGuest

"jamestuck21" <> writes:

> An example that I worked out with the correct solution is not the same
> as the windows calculator is giving
>
> 1001 / 101110000
>
> Solution = 101011 with Remainder of 011 and the remainder is what I'm
> interested in.

There's no way that the quotient to that division can be 101011.
That's as silly as saying that 1234 / 123456789 = 456789.
Dividing a small number by a large number yields 0, with the
small number as remainder.
--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan

Ben Pfaff, Dec 1, 2006
8. ### jamestuck21Guest

This is an example on calculating the remainder in use with CRC. Maybe
I might of not explained it properly, but that is the correct solution
and this is using binary division to get a quotient and specifically
interested in the remainder value because that is the extra amount of
bits tacked onto a file for checksum.

Ben Pfaff wrote:
> "jamestuck21" <> writes:
>
> > An example that I worked out with the correct solution is not the same
> > as the windows calculator is giving
> >
> > 1001 / 101110000
> >
> > Solution = 101011 with Remainder of 011 and the remainder is what I'm
> > interested in.

>
> There's no way that the quotient to that division can be 101011.
> That's as silly as saying that 1234 / 123456789 = 456789.
> Dividing a small number by a large number yields 0, with the
> small number as remainder.
> --
> "Debugging is twice as hard as writing the code in the first place.
> Therefore, if you write the code as cleverly as possible, you are,
> by definition, not smart enough to debug it."
> --Brian Kernighan

jamestuck21, Dec 1, 2006
9. ### Coos HaakGuest

Op 30 Nov 2006 16:23:36 -0800 schreef jamestuck21:

> Windows calculator does not give the correct solution.
>
> An example that I worked out with the correct solution is not the same
> as the windows calculator is giving
>
> 1001 / 101110000
>
> Solution = 101011 with Remainder of 011 and the remainder is what I'm
> interested in.
>
>
> Al Balmer wrote:
>> On 30 Nov 2006 10:27:57 -0800, "jamestuck21" <>
>> wrote:
>>
>>> Does anyone know of a simple web
>>>calculator that I can check against my answer or if someone could run
>>>through this example with me, that would be great. thank you

>>
>> Does it have to be on the web? Since you're appear to be posting from
>> Windows, I'd suggest the Windows calculator, in scientific mode.
>>
>> 11100011100

<OT>
Why didn't you use the 'MOD' button on the Windows calculator?
(I am lucky to know Forth, '/MOD' gives the quotient and remaider at once.)
</OT>
--
Coos

Coos Haak, Dec 1, 2006
10. ### jamestuck21Guest

The mod button does not give you the correct solution. It just returns
the original value that you're trying to use to divide into.

Coos Haak wrote:
> Op 30 Nov 2006 16:23:36 -0800 schreef jamestuck21:
>
> > Windows calculator does not give the correct solution.
> >
> > An example that I worked out with the correct solution is not the same
> > as the windows calculator is giving
> >
> > 1001 / 101110000
> >
> > Solution = 101011 with Remainder of 011 and the remainder is what I'm
> > interested in.
> >
> >
> > Al Balmer wrote:
> >> On 30 Nov 2006 10:27:57 -0800, "jamestuck21" <>
> >> wrote:
> >>
> >>> Does anyone know of a simple web
> >>>calculator that I can check against my answer or if someone could run
> >>>through this example with me, that would be great. thank you
> >>
> >> Does it have to be on the web? Since you're appear to be posting from
> >> Windows, I'd suggest the Windows calculator, in scientific mode.
> >>
> >> 11100011100

> <OT>
> Why didn't you use the 'MOD' button on the Windows calculator?
> (I am lucky to know Forth, '/MOD' gives the quotient and remaider at once.)
> </OT>
> --
> Coos

jamestuck21, Dec 1, 2006
11. ### Coos HaakGuest

Op 30 Nov 2006 16:49:25 -0800 schreef jamestuck21:
Top-posting corrected.

> Coos Haak wrote:
>> Op 30 Nov 2006 16:23:36 -0800 schreef jamestuck21:
>>
>>> Windows calculator does not give the correct solution.
>>>
>>> An example that I worked out with the correct solution is not the same
>>> as the windows calculator is giving
>>>
>>> 1001 / 101110000
>>>
>>> Solution = 101011 with Remainder of 011 and the remainder is what I'm
>>> interested in.
>>>
>>>
>>> Al Balmer wrote:
>>>> On 30 Nov 2006 10:27:57 -0800, "jamestuck21" <>
>>>> wrote:
>>>>
>>>>> Does anyone know of a simple web
>>>>>calculator that I can check against my answer or if someone could run
>>>>>through this example with me, that would be great. thank you
>>>>
>>>> Does it have to be on the web? Since you're appear to be posting from
>>>> Windows, I'd suggest the Windows calculator, in scientific mode.
>>>>
>>>> 11100011100

>> <OT>
>> Why didn't you use the 'MOD' button on the Windows calculator?
>> (I am lucky to know Forth, '/MOD' gives the quotient and remaider at once.)
>> </OT>

> The mod button does not give you the correct solution. It just returns
> the original value that you're trying to use to divide into.
>

Of course, the quotient is zero, so the remainder is the dividend, like Ben
Pfaff said. Simple maths.
--
Coos

Coos Haak, Dec 1, 2006
12. ### MichaelGuest

> Windows calculator does not give the correct solution.
>
> An example that I worked out with the correct solution is not the same
> as the windows calculator is giving
>
> 1001 / 101110000
>
> Solution = 101011 with Remainder of 011 and the remainder is what I'm
> interested in.

It appears from your scratch calculations in previous posts that you
really want to do 101110000 / 1001, i.e., 1001 divided into 101110000,
not divided by.

My copy of Windows calculator does this correctly. Converting to
decimal, the example you gave above is 368 / 9. The answer is 40, with
a remainder of 8, not 43 (= 101011 binary) with a remainder of 3 (= 011
binary) as you're claiming.

Michael

Michael, Dec 1, 2006
13. ### MQGuest

jamestuck21 wrote:
> The mod button does not give you the correct solution. It just returns
> the original value that you're trying to use to divide into.

Yes, and why is this not correct. What answer are you expecting? When
the dividend is smaller than the divisor the answer is always 0 rem
dividend.

MQ, Dec 1, 2006
14. ### jamestuck21Guest

I'm sorry, but the division that's taking place in calculating the CRC
doesn't seem to match what you guys are saying. I have a concrete
example that I'm using which is 1001 divided into 101110000 returns a
solution of 101011 and 011 as the remainder. This was an example in
calculating a CRC problem done for us. I'll consult our professor in
this question, because it doesn't seem that you guys know how to
calculate the additional bit for the CRC checksum through this type of
binary division. Thanks for trying though.

MQ wrote:
> jamestuck21 wrote:
> > The mod button does not give you the correct solution. It just returns
> > the original value that you're trying to use to divide into.

>
> Yes, and why is this not correct. What answer are you expecting? When
> the dividend is smaller than the divisor the answer is always 0 rem
> dividend.

jamestuck21, Dec 1, 2006
15. ### MQGuest

jamestuck21 wrote:
> I'm sorry, but the division that's taking place in calculating the CRC
> doesn't seem to match what you guys are saying. I have a concrete
> example that I'm using which is 1001 divided into 101110000 returns a
> solution of 101011 and 011 as the remainder. This was an example in
> calculating a CRC problem done for us. I'll consult our professor in
> this question, because it doesn't seem that you guys know how to
> calculate the additional bit for the CRC checksum through this type of
> binary division. Thanks for trying though.

I think there may be some confusion from your original post. You
posted 1100 / 101010101010111 , whereas I think you meant to say
101010101010111 / 1100. The answer to this is 1820 remainder 7, or
11100011100 remainder 111 in binary. Does this help?

MQ, Dec 1, 2006
16. ### CBFalconerGuest

*** rude top-posting fixed ***
jamestuck21 wrote:
> Al Balmer wrote:
>> "jamestuck21" <> wrote:
>>
>>> Does anyone know of a simple web
>>> calculator that I can check against my answer or if someone could
>>> run through this example with me, that would be great. thank you

>>
>> Does it have to be on the web? Since you're appear to be posting from
>> Windows, I'd suggest the Windows calculator, in scientific mode.

>
> Windows calculator does not give the correct solution.
>
> An example that I worked out with the correct solution is not the same
> as the windows calculator is giving
>
> 1001 / 101110000
>
> Solution = 101011 with Remainder of 011 and the remainder is what I'm
> interested in.

Which is not the correct answer. Are you incapable of dividing 9
by 368 (decimal) and getting a remainder of 9? Even if you have
the operands exchanged, the remainder would be 8, not 3 and the
quotient would be 40, not 43.

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net>

CBFalconer, Dec 1, 2006
17. ### Keith ThompsonGuest

"jamestuck21" <> writes:
> I'm sorry, but the division that's taking place in calculating the CRC
> doesn't seem to match what you guys are saying. I have a concrete
> example that I'm using which is 1001 divided into 101110000 returns a
> solution of 101011 and 011 as the remainder. This was an example in
> calculating a CRC problem done for us. I'll consult our professor in
> this question, because it doesn't seem that you guys know how to
> calculate the additional bit for the CRC checksum through this type of
> binary division. Thanks for trying though.

http://www.caliburn.nl/topposting.html
http://www.cpax.org.uk/prg/writings/topposting.php

If we don't know how to do CRC checksums, it's probably because this
is a newsgroup for discussing the C programming language. I have yet
to see a posting in this thread that has anything to do with C. I'm
not sure what newsgroup would be more appropriate; comp.programming
*might* be a better starting point.

--
Keith Thompson (The_Other_Keith) <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

Keith Thompson, Dec 1, 2006
18. ### jamestuck21Guest

Well my original post was for a seperate problem that I had to work on,
but I can't get everyone to agree to the example that we've been
talking about so I dont' know if what you say is 100% correct. I think
I'm going to just get this clarified by my professor since he'll know
how to do the binary division in terms of generating the CRC bits.
Again, thanks for everyone's help in trying.

MQ wrote:
> jamestuck21 wrote:
> > I'm sorry, but the division that's taking place in calculating the CRC
> > doesn't seem to match what you guys are saying. I have a concrete
> > example that I'm using which is 1001 divided into 101110000 returns a
> > solution of 101011 and 011 as the remainder. This was an example in
> > calculating a CRC problem done for us. I'll consult our professor in
> > this question, because it doesn't seem that you guys know how to
> > calculate the additional bit for the CRC checksum through this type of
> > binary division. Thanks for trying though.

>
> I think there may be some confusion from your original post. You
> posted 1100 / 101010101010111 , whereas I think you meant to say
> 101010101010111 / 1100. The answer to this is 1820 remainder 7, or
> 11100011100 remainder 111 in binary. Does this help?

jamestuck21, Dec 1, 2006
19. ### jamestuck21Guest

I just figured out the problem. Thanks again.

jamestuck21, Dec 1, 2006

Michael wrote:
>>Windows calculator does not give the correct solution.
>>
>>An example that I worked out with the correct solution is not the same
>>as the windows calculator is giving
>>
>>1001 / 101110000
>>
>>Solution = 101011 with Remainder of 011 and the remainder is what I'm
>>interested in.

>
>
> It appears from your scratch calculations in previous posts that you
> really want to do 101110000 / 1001, i.e., 1001 divided into 101110000,
> not divided by.
>
> My copy of Windows calculator does this correctly. Converting to
> decimal, the example you gave above is 368 / 9. The answer is 40, with
> a remainder of 8, not 43 (= 101011 binary) with a remainder of 3 (= 011
> binary) as you're claiming.

What the OP failed to mention is that he isn't dividing binary numbers,
but CRC polynomials with arithmetic modulo 2. See
http://www.relisoft.com/Science/CrcNaive.html
as an example.

--