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Groups > comp.lang.c++ > #4291
| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: Problem with array objects |
| Date | 2011-04-24 09:26 +1200 |
| Message-ID | <91guh2F6cmU1@mid.individual.net> (permalink) |
| References | (2 earlier) <eg1rp.4730$9h6.2764@newsfe02.ams2> <slrniqrm4f.2usb.aggedor@earl-grey.cloud9.net> <ZuTrp.20047$Vm5.2779@newsfe30.ams2> <slrnir64sj.pso.aggedor@earl-grey.cloud9.net> <%OFsp.42022$bT6.13973@newsfe05.ams2> |
On 04/24/11 07:31 AM, Paul wrote:
>
> "A. Bolmarcich"<aggedor@earl-grey.cloud9.net> wrote in message
> news:slrnir64sj.pso.aggedor@earl-grey.cloud9.net...
>> On 2011-04-20, Paul<pchristor@yahoo.co.uk> wrote:
>>>
>>> "A. Bolmarcich"<aggedor@earl-grey.cloud9.net> wrote in message
>>> news:slrniqrm4f.2usb.aggedor@earl-grey.cloud9.net...
>> [snip]
>>>> A pointer to an array of 4 ints, when dereferenced, returns an array
>>>> of 4 ints. Look at the output of running the following program.
>>>>
>>>> #include<iostream>
>>>> #include<typeinfo>
>>>>
>>>> int main() {
>>>> int a1i[4], (*pa1i)[4] =&a1i;
>>>>
>>>> std::cout<<"typeid( a1i)="<<typeid(a1i).name()<<std::endl;
>>>> std::cout<<"typeid(*pa1i)="<<typeid(*pa1i).name()<<std::endl;
>>>> }
>>>>
>>> You are dereferencing an array-type , not an array.
>>> For example:
>>>
>>> int arr[40] ={0};
>>> int* parr = arr;
>>> int (*pparr)[40] =&arr;
>>>
>>> std::cout<< "address of arr[0]:\t"<< &arr[0]<<std::endl;
>>> std::cout<< "value of *parr:\t\t"<< *parr<<std::endl;
>>> std::cout<< "value of *pparr\t\t"<< *pparr<<std::endl;
>>>
>>> Dereferencing pparr does not access the array it accesses a temporary
>>> pointer.
>>> The pointer pparr does not reference the array, it references an
>>> array-type
>>> object.
>>
>> Dereferencing pparr accesses an array in the same sense that using
>> the name arr accesses an array.
> No it doesn't
All together now - oh yes it does!
try adding
(*pparr)[0] = 42;
std::cout<< "value of arr[0]\t\t" << arr[0] <<std::endl;
arr[10] = 1234;
std::cout<< "value of (*pparr)[0]\t\t" << (*pparr)[10] <<std::endl;
--
Ian Collins
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Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-04-18 12:44 -0500
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-18 21:35 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-04-19 13:46 -0500
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-20 17:29 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-04-23 12:59 -0500
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-23 20:31 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-24 09:26 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-24 00:04 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-24 11:24 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-24 02:16 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-24 14:10 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-24 04:37 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-24 16:11 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-24 13:31 +0100
Re: Problem with array objects Peter Remmers <p.remmers@expires-2011-04-30.arcornews.de> - 2011-04-24 17:57 +0200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-24 17:39 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-25 10:19 +1200
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-25 10:12 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-25 00:46 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-25 11:59 +1200
Re: Problem with array objects "Alf P. Steinbach /Usenet" <alf.p.steinbach+usenet@gmail.com> - 2011-04-25 05:01 +0200
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-04-25 14:56 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-25 10:57 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-04-26 12:36 -0500
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-26 22:42 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-04-27 12:53 -0500
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-04-27 19:06 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-27 20:09 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-04-29 12:57 -0500
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-04-29 19:10 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-04-29 19:56 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-05-02 13:20 -0500
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-02 22:43 +0100
Re: Problem with array objects "A. Bolmarcich" <aggedor@earl-grey.cloud9.net> - 2011-05-05 14:13 -0500
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-05 22:21 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-05-06 10:49 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-06 12:29 +0100
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