Re: Comparing strings pointed by * CStringA

From:
wojjed@gmail.com
Newsgroups:
microsoft.public.vc.mfc
Date:
Mon, 1 Sep 2008 03:16:53 -0700 (PDT)
Message-ID:
<67f0d1fd-9e38-41d0-8b91-b7e0e272d686@j22g2000hsf.googlegroups.com>
On 1 Wrz, 10:34, "Giovanni Dicanio"
<giovanniDOTdica...@REMOVEMEgmail.com> wrote:

<woj...@gmail.com> ha scritto nel messaggionews:6919bf24-d4ae-4500-bd95-7=

59018406993@w7g2000hsa.googlegroups.com...

retirve values from my table. If column insqlvas "varchar" , the
object of CDBVariant is *CStringA type. I need to compare two
pointers of CStringA . For example prt1 points on "ID1" and ptr2
points on "ID2". If there is a CStringA type, there is no problem, but
when i got pointers to CStringA types, i completly dont know how to
compare strings pointed by them.


Please correct me if I'm wrong, but my understanding is that you have:

 CStringA * pstr1 ...
 CStringA * pstr2 ...

and you want co compare pstr1 with pstr2.

If you had

 // no pointers
 CStringA str1 ...
 CStringA str2 ...

you would probably do str1.Compare( str2 ).

If you have pointers, you can dereference them:

  pstr1->Compare( *pstr2 );

Which is equivalent to more verbose:

  (*pstr1).Compare( *pstr2 );

Basically, if 'pstr' is a 'CStringA *', then '*pstr' is a 'CStringA'.

HTH,
Giovanni


Yes, that is what i was looking for. Another thing is that i got
"strange" errors when im trying to retrive data from database - code
below:

CDBVariant varValue;
CStringA *pstr;

pstr = new CStringA;
pstr = varValue.m_pstringA;

when im using Find method i got unhandled exeption and complier visual
stopts at " int GetLength() const throw()
    {
        return( GetData()->nDataLength );
    }" from altsimpstr.h
im typieg :
pstr -> Find(_T("ID0"),0)

when im debugging, and move coursor at that line, it shows me : psrt =
<Bad Ptr>
why ? whats wrong ?

WJ

(now pstr is "ID0ID2ID3")

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