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Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;)

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"Heikki Kallasjoki"  wrote in message news:slrnjra97k.d62.fis@iris.zem.fi...

On 2012-05-17, Skybuck Flying <Windows7IsOK@DreamPC2006.com> wrote:
>> private static void rangeCheck(int arrayLen, int fromIndex, int toIndex) 
>> {
>>     if (fromIndex > toIndex)
>>         throw new IllegalArgumentException("fromIndex(" + fromIndex +
>>                    ") > toIndex(" + toIndex+")");
>>     if (fromIndex < 0)
>>         throw new ArrayIndexOutOfBoundsException(fromIndex);
>>     if (toIndex > arrayLen)
>>         throw new ArrayIndexOutOfBoundsException(toIndex);
>> }

> A very perverse way. The mission is to check if indexes are outside the
> array "out of bounds".
>
> Furthermore it makes no sense, copieing from high to low should be 
> possible

"
Who said anything about copying?
"

It seems likely this code is called right before the array is accessed to 
try and prevent an access violation, instead it tries to throw a somewhat 
nicer exception message to indicate a problem with array access.

(Reading/writing to an array can be considered "copieing").

"
I believe it is checking whether the range fromIndex, fromIndex+1, ...,
toIndex-1 -- i.e., a range given as the first index and one past the
last index, not an uncommon practice -- is within the array, in which
case it has no bugs.  (toIndex may legally equal the length of the array
when the range extends to the last element, and requiring the range to
be specified "the right way around" is not especially perverse.)
"

It's simply not valid. Out of bounds has a very clear meaning in programming 
practice. It's either within bounds or it's not. The bounds of a java array 
are very clearly defined. Thus the only logical conclusion is that the code 
is simply bugged.
Either in logic or in description. Either change the exception-description 
or fix the code.

If this were some stack based structure then it would make sense that the 
index could go one beyond the size. However it's not a stack, but an array.

The perversity is not with checking if "to" is beyond "from". The perversity 
is the logical dependency of the "from" out of bounds check onto the "to" 
out of bounds check.

Both indexes can be considered separate indexes and there a simply routine 
which would check each index individually would be better/preferred.

However this routine seems to try and do multiple tasks all at once, which 
is another bad coding practice.

Therefore advice:

1. Split routine up into two separate routines:

First routine to check if a single index is out of bounds.

Second routine to check if the indexes are in proper order.

Further more checking the indexes independently might even execute faster 
because of instruction level parallelism, so this attempted optimization 
might actually be counter productive, except for perhaps less instruction 
decoding.

The call overhead of using multiple routines could be counter acted by 
inlining features. I am not sure if java has "inlining" support.

Bye,
  Skybuck.

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Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-17 15:09 +0200
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-17 09:23 -0400
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-17 17:26 +0200
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Heikki Kallasjoki <fis+usenet@zem.fi> - 2012-05-17 16:19 +0000
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-17 19:57 +0200
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-05-17 18:33 +0000
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-17 23:25 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <lewbloch@gmail.com> - 2012-05-17 14:52 -0700
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-05-17 14:58 -0700
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-17 17:59 -0400
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Heikki Kallasjoki <fis+usenet@zem.fi> - 2012-05-17 22:13 +0000
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-18 01:18 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-17 21:32 -0400
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Noob <root@127.0.0.1> - 2012-05-18 17:08 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-19 20:53 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-19 21:19 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-05-19 18:47 -0700
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-20 17:55 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-19 20:18 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-19 20:21 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-19 20:52 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:27 -0400
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <noone@lewscanon.com> - 2012-05-19 14:48 -0700
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <noone@lewscanon.com> - 2012-05-19 15:20 -0700
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <noone@lewscanon.com> - 2012-05-19 15:35 -0700
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:25 -0400
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) bugbear <bugbear@trim_papermule.co.uk_trim> - 2012-05-21 17:12 +0100
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Heikki Kallasjoki <fis+usenet@zem.fi> - 2012-05-18 07:22 +0000
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <noone@lewscanon.com> - 2012-05-19 14:50 -0700
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:21 -0400
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:23 -0400
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-18 01:09 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:14 -0400
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 09:36 +0200
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-20 17:53 +0200
            Re: names for parameters of ranges Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:30 -0400
              Re: names for parameters of ranges Gene Wirchenko <genew@ocis.net> - 2012-05-20 20:48 -0700
            Re: names for parameters of ranges (was: ...) Willem <willem@toad.stack.nl> - 2012-05-23 09:43 +0000
              Re: names for parameters of ranges Willem <willem@toad.stack.nl> - 2012-05-23 11:07 +0000
                Re: names for parameters of ranges Willem <willem@toad.stack.nl> - 2012-05-23 15:42 +0000
              Re: names for parameters of ranges Willem <willem@toad.stack.nl> - 2012-05-23 11:11 +0000
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Heikki Kallasjoki <fis+usenet@zem.fi> - 2012-05-17 19:13 +0000
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Heikki Kallasjoki <fis+usenet@zem.fi> - 2012-05-17 19:19 +0000
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Jim Janney <jjanney@shell.xmission.com> - 2012-05-17 18:35 -0600
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-17 23:16 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:32 -0400
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 09:40 +0200
                Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-21 10:05 -0400
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 14:41 -0400
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:12 -0400
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Keith Thompson <kst-u@mib.org> - 2012-05-20 16:38 -0700
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <noone@lewscanon.com> - 2012-05-20 18:52 -0700
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Keith Thompson <kst-u@mib.org> - 2012-05-20 19:21 -0700
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) gazelle@shell.xmission.com (Kenny McCormack) - 2012-05-21 08:24 +0000
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Bill Leary" <Bill_Leary@msn.com> - 2012-05-23 14:34 -0400
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-05-20 21:46 -0600
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <noone@lewscanon.com> - 2012-05-21 00:04 -0700
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) gazelle@shell.xmission.com (Kenny McCormack) - 2012-05-21 08:25 +0000
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 09:46 +0200
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) jacob navia <jacob@spamsink.net> - 2012-05-17 18:54 +0200
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Mark Storkamp <mstorkamp@yahoo.com> - 2012-05-17 12:06 -0500
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) markspace <-@.> - 2012-05-17 10:11 -0700
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <lewbloch@gmail.com> - 2012-05-17 14:43 -0700
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) markspace <-@.> - 2012-05-17 16:13 -0700
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) markspace <-@.> - 2012-05-17 16:42 -0700
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Jan Burse <janburse@fastmail.fm> - 2012-05-18 02:27 +0200
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 15:06 -0400
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Marius" <sorry@nospamfor.me> - 2012-05-17 17:32 +0000
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-17 23:45 +0200
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Marius" <sorry@nospamfor.me> - 2012-05-17 22:16 +0000
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-18 00:47 +0200
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-24 14:11 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-24 14:17 +0200
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Roedy Green <see_website@mindprod.com.invalid> - 2012-05-18 02:57 -0700
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-05-18 05:26 -0500
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-18 08:08 -0400
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 14:46 -0400
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) rossum <rossum48@coldmail.com> - 2012-05-18 12:25 +0100
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Gene Wirchenko <genew@ocis.net> - 2012-05-18 10:46 -0700
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-19 21:01 +0200
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:33 -0400
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Patricia Shanahan <pats@acm.org> - 2012-05-20 16:30 -0700
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Gene Wirchenko <genew@ocis.net> - 2012-05-20 20:36 -0700
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Kaz Kylheku <kaz@kylheku.com> - 2012-05-21 04:28 +0000
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 09:55 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 09:49 +0200
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-21 10:08 -0400
          Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 10:45 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 11:13 +0200
            Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 11:19 +0200
              Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <lewbloch@gmail.com> - 2012-05-21 11:40 -0700
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-20 18:10 -0400
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-21 10:00 +0200
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-05-21 10:10 -0400
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) falk@rahul.net (Edward A. Falk) - 2012-05-23 05:40 +0000
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Jim Janney <jjanney@shell.xmission.com> - 2012-05-23 08:46 -0600
    Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2012-05-24 14:03 +0200
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Lew <lewbloch@gmail.com> - 2012-05-24 09:56 -0700
      Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) falk@rahul.net (Edward A. Falk) - 2012-05-26 00:52 +0000
        Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> - 2012-05-25 21:16 -0400
  Re: Oracle/Google demonstrate human beings cannot write 10 lines of code without making a mistake ;) Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2012-05-24 09:42 -0700

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