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Re: Bignumb addition function, suggestion improvements.

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Den söndag 15 mars 2015 kl. 00:51:35 UTC+1 skrev Dr....@nyc.rr.com:
> On Sat, 14 Mar 2015 04:15:24 -0700 (PDT), jonas.thornvall@gmail.com wrote
> in <f9fe170d-9fdf-42bf-9fca-23a3bc48f76c@googlegroups.com>:
> 
> >I just wrote a big numb addition function this morning, it is a bit silly and naive, not pure string not pure integer. I think it is correct, but i may have missed leading last digit.
> >
> >Suggestions to write it shorter and more clear, but keeping the naive approach appreciated.
> <snip>
> 
> There are zillions of things to play with doing this.   :)
> 
> The first thing that comes to mind is what was on the back cover of grade
> school notebooks since before The War (that's WWII) -- tables.  More
> precisely addition and multiplication tables.  Simply two dimensional
> arrays to give the sum or product of the two digits.  (Actually they went
> up to 12 by 12.)  Rather than doing your addition just look up the sum and
> carry.
> 
> And stop your laughing -- this was the method that was used in BCD machines
> a half century ago!  In one computer I used, those tables were in regular
> memory and I reset them to do octal arithmetic instead of decimal.
> 
> It would make more sense to make sure your strings are all numeric before
> you start rather than during the calculation. 

Actually i was more in favor for skipping using the built in math operators all together, just doing string manipulations but that would required a table. And i am unsure how well such approach would have coped with changing base doing addition. I think i basicly only need exchange 10 with a variable that it a parameter that passed at function call to change base for the addition.


 You only have to add for the
> number of digits of the shorter string and then add the carry to the left
> portion of the longer one and concatenate.  Alternatively, you can left pad
> the shorter one with zeros to make them the same length.  That what you do
> when you add manually (when learning). 
> 
> Also, pad the longer one first with a 0 and then the last carry is not
> special.
> 
> Have fun.
> 
> K

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Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-14 04:15 -0700
  Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-14 04:40 -0700
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-14 04:56 -0700
  Re: Bignumb addition function, suggestion improvements. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-03-14 13:41 +0000
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-14 10:17 -0700
      Re: Bignumb addition function, suggestion improvements. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-03-14 19:39 +0000
        Re: Bignumb addition function, suggestion improvements. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-03-14 20:56 +0100
        Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 01:52 -0700
          Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 02:57 -0700
            Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 03:07 -0700
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-14 10:57 -0700
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 03:40 -0700
      Re: Bignumb addition function, suggestion improvements. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-03-15 11:06 +0000
      Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 04:09 -0700
  Re: Bignumb addition function, suggestion improvements. Dr.Kral@nyc.rr.com - 2015-03-14 19:51 -0400
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-14 23:57 -0700
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 00:08 -0700
  Re: Bignumb addition function, suggestion improvements. John Harris <niam@jghnorth.org.uk.invalid> - 2015-03-15 10:46 +0000
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 04:12 -0700
      Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 06:00 -0700
    Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 04:27 -0700
      Re: Bignumb addition function, suggestion improvements. jonas.thornvall@gmail.com - 2015-03-15 05:30 -0700

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