ANDing and ORing question...

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  • MLH
    #1

    ANDing and ORing question...

    If I have an integer A and I logically AND it
    with some other integer B to produce a result
    C, can I then perform some kind of reverse
    operation with B and C to get back the original
    number A?

    If so, is it guaranteed to work every time with
    all integers A and B?
    Tags: None
    • Bas Cost Budde
      #2
      Re: ANDing and ORing question...

      No!
      With AND, you may set one or more bits in A to zero. That information is
      then lost.

      MLH wrote:
      [color=blue]
      > If I have an integer A and I logically AND it
      > with some other integer B to produce a result
      > C, can I then perform some kind of reverse
      > operation with B and C to get back the original
      > number A?
      >
      > If so, is it guaranteed to work every time with
      > all integers A and B?[/color]

      --
      Bas Cost Budde, Holland
      http://www.heuveltop.nl/BasCB/msac_index.html

      For human replies, replace the queue with a tea

        Comment

        • Tom van Stiphout
          #3
          Re: ANDing and ORing question...

          On Sat, 02 Jul 2005 14:13:10 -0400, MLH <CRCI@NorthStat e.net> wrote:

          That's why we have XOR:

          Sub x2()
          Dim A As Integer
          Dim B As Integer

          A = 10 ' or any other number
          B = 20 ' or any other number
          A = A Xor B
          A = A Xor B
          Debug.Print A

          End Sub


          [color=blue]
          >If I have an integer A and I logically AND it
          >with some other integer B to produce a result
          >C, can I then perform some kind of reverse
          >operation with B and C to get back the original
          >number A?
          >
          >If so, is it guaranteed to work every time with
          >all integers A and B?[/color]

            Comment

            • Mike MacSween
              #4
              Re: ANDing and ORing question...

              "MLH" <CRCI@NorthStat e.net> wrote in message
              news:04mdc1d0dq hem1hmqtf95t0kr b5durmmpm@4ax.c om...[color=blue]
              > If I have an integer A and I logically AND it
              > with some other integer B to produce a result
              > C, can I then perform some kind of reverse
              > operation with B and C to get back the original
              > number A?[/color]

              Wwwwwhhhhhhhhhh aaaaaaaaaaaaaat ttttttttttttttt ?


                Comment

                • Mike MacSween
                  #5
                  Re: ANDing and ORing question...

                  Oh I see

                  "Bas Cost Budde" <b.costbudde@he uvelqop.nl> wrote in message
                  news:da6sdo$ii6 $6@localhost.lo caldomain...[color=blue]
                  > No!
                  > With AND, you may set one or more bits in A to zero. That information is
                  > then lost.
                  >
                  > MLH wrote:
                  >[color=green]
                  >> If I have an integer A and I logically AND it
                  >> with some other integer B to produce a result
                  >> C, can I then perform some kind of reverse
                  >> operation with B and C to get back the original
                  >> number A?
                  >>
                  >> If so, is it guaranteed to work every time with
                  >> all integers A and B?[/color]
                  >
                  > --
                  > Bas Cost Budde, Holland
                  > http://www.heuveltop.nl/BasCB/msac_index.html
                  > For human replies, replace the queue with a tea
                  >[/color]


                    Comment

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