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Re: (simple?) problem with multiplication

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On 2011-06-21 14:04:37 -0400, Ttodir said:

> Hello,
> 
> I need a fast way to calculate (a * b) % B, with the following
> constraints:
> 
> - a, b, B are int
> - B = 10^N , N>0 arbitrary (B always fits in an int)
> - the result must be valid even if the multiplication overflows
> - portable code, no assumptions on the sizeof(int) and no types larger
> than int can be used.
> 
> Any help will be much appreciated.

Read about greatest common divisors.

-- 
  Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The 
Standard C++ Library Extensions: a Tutorial and Reference 
(www.petebecker.com/tr1book)

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(simple?) problem with multiplication Ttodir <sanmrtn96@gmail.com> - 2011-06-21 11:04 -0700
  Re: (simple?) problem with multiplication Ttodir <sanmrtn96@gmail.com> - 2011-06-21 11:11 -0700
  Re: (simple?) problem with multiplication "Balog Pal" <pasa@lib.hu> - 2011-06-21 20:35 +0200
    Re: (simple?) problem with multiplication Anonymous <anonymous@no.net> - 2011-06-21 20:45 +0200
    Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-21 14:46 -0400
      Re: (simple?) problem with multiplication Ttodir <sanmrtn96@gmail.com> - 2011-06-21 12:03 -0700
        Re: (simple?) problem with multiplication Gido <gido0001@gmail.com> - 2011-06-21 14:30 -0700
          Re: (simple?) problem with multiplication Anonymous <anonymous@no.net> - 2011-06-21 23:32 +0200
          Re: (simple?) problem with multiplication Juha Nieminen <nospam@thanks.invalid> - 2011-06-23 06:33 +0000
  Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-21 14:40 -0400
  Re: (simple?) problem with multiplication Christopher <cpisz@austin.rr.com> - 2011-06-21 11:39 -0700
  Re: (simple?) problem with multiplication Anonymous <anonymous@no.net> - 2011-06-21 23:32 +0200
    Re: (simple?) problem with multiplication Kai-Uwe Bux <jkherciueh@gmx.net> - 2011-06-21 23:41 +0200
  Re: (simple?) problem with multiplication Rune Allnor <allnor@tele.ntnu.no> - 2011-06-21 21:33 -0700
    Re: (simple?) problem with multiplication Ttodir <sanmrtn96@gmail.com> - 2011-06-22 04:59 -0700
  Re: (simple?) problem with multiplication gwowen <gwowen@gmail.com> - 2011-06-22 06:55 -0700
    Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-22 10:10 -0400
      Re: (simple?) problem with multiplication Leigh Johnston <leigh@i42.co.uk> - 2011-06-22 15:19 +0100
        Re: (simple?) problem with multiplication Dilip <rdilipk@gmail.com> - 2011-06-22 07:33 -0700
          Re: (simple?) problem with multiplication Leigh Johnston <leigh@i42.co.uk> - 2011-06-22 15:39 +0100
            Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-22 11:02 -0400
              Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-23 23:45 +0100
          Re: (simple?) problem with multiplication gwowen <gwowen@gmail.com> - 2011-06-22 23:59 -0700
      Re: (simple?) problem with multiplication gwowen <gwowen@gmail.com> - 2011-06-22 23:50 -0700
        Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-23 09:26 +0100
  Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-22 21:24 +0100
    Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-24 00:00 +0100
  Re: (simple?) problem with multiplication gwowen <gwowen@gmail.com> - 2011-06-24 01:42 -0700
    Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-24 10:47 +0100
  Re: (simple?) problem with multiplication SG <s.gesemann@gmail.com> - 2011-06-24 10:09 -0700
    Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-24 13:32 -0400
      Re: (simple?) problem with multiplication Kai-Uwe Bux <jkherciueh@gmx.net> - 2011-06-24 20:07 +0200
        Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-24 14:14 -0400
          Re: (simple?) problem with multiplication Kai-Uwe Bux <jkherciueh@gmx.net> - 2011-06-24 20:28 +0200
            Re: (simple?) problem with multiplication Pete Becker <pete@versatilecoding.com> - 2011-06-24 16:26 -0400
              Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-25 03:01 +0100
                Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-25 18:20 +0100
            Re: (simple?) problem with multiplication "Alf P. Steinbach /Usenet" <alf.p.steinbach+usenet@gmail.com> - 2011-06-25 04:21 +0200
            Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-25 10:12 +0100
              Re: (simple?) problem with multiplication SG <s.gesemann@gmail.com> - 2011-06-25 02:51 -0700
                Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-25 11:19 +0100
                Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-25 11:19 +0100
                Re: (simple?) problem with multiplication Gareth Owen <gwowen@gmail.com> - 2011-06-26 07:59 +0100
                Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-26 12:34 +0100
          Re: (simple?) problem with multiplication SG <s.gesemann@gmail.com> - 2011-06-25 02:37 -0700
        Re: (simple?) problem with multiplication Gareth Owen <gwowen@gmail.com> - 2011-06-25 08:58 +0100
          Re: (simple?) problem with multiplication "Paul" <pchristor@yahoo.co.uk> - 2011-06-25 10:00 +0100
          Re: (simple?) problem with multiplication Kai-Uwe Bux <jkherciueh@gmx.net> - 2011-06-25 10:29 +0200

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