Binary Division Problem Help

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

  1. jamestuck21

    jamestuck21 Guest

    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
    #1
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  2. jamestuck21

    santosh Guest

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

    <snip>

    Post to sci.math
    santosh, Nov 30, 2006
    #2
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  3. jamestuck21

    Ben Pfaff Guest

    "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
    #3
  4. "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

    Your first question asks how to take A/B

    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
    #4
  5. jamestuck21

    Al Balmer Guest

    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
    #5
  6. jamestuck21

    jamestuck21 Guest

    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
    #6
  7. jamestuck21

    Ben Pfaff Guest

    "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
    #7
  8. jamestuck21

    jamestuck21 Guest

    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
    #8
  9. jamestuck21

    Coos Haak Guest

    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
    #9
  10. jamestuck21

    jamestuck21 Guest

    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
    #10
  11. jamestuck21

    Coos Haak Guest

    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
    #11
  12. jamestuck21

    Michael Guest

    > 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
    #12
  13. jamestuck21

    MQ Guest

    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
    #13
  14. jamestuck21

    jamestuck21 Guest

    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
    #14
  15. jamestuck21

    MQ Guest

    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
    #15
  16. jamestuck21

    CBFalconer Guest

    *** 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.

    Please do not top-post.

    --
    Chuck F (cbfalconer at maineline dot net)
    Available for consulting/temporary embedded and systems.
    <http://cbfalconer.home.att.net>
    CBFalconer, Dec 1, 2006
    #16
  17. "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.


    Please don't top post. Read the following:

    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
    #17
  18. jamestuck21

    jamestuck21 Guest

    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
    #18
  19. jamestuck21

    jamestuck21 Guest

    I just figured out the problem. Thanks again.
    jamestuck21, Dec 1, 2006
    #19
  20. jamestuck21

    Thad Smith Guest

    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.

    --
    Thad
    Thad Smith, Dec 1, 2006
    #20
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