Location of entry in database -help!ADO - C / C++ / MFC Discussion Boards

cadinfo10-Sep-02 2:57

10-Sep-02 2:57

Your reply sounds reasonable, but both the varibale of 'ca' and 'cb' have same address in memory, but their value is different, I just can't unstand it, it must be somewhere else for 'ca' or 'cb', is that correct!

Re: Guess what output, and tell me why?

jhwurmbach10-Sep-02 3:56

jhwurmbach

10-Sep-02 3:56

cadinfo wrote:
, but both the varibale of 'ca' and 'cb' have same address in memory

After the compiler optimization, 'ca' has NO address in memory any more. It simply is the value '200' known at compile time.
You promised not to change this value by declaring it const, remember?
So the compiler can replace every access to 'ca' by the value '200' at compile time.
In effect, this is a little like a precompiler #define, in that both methods don't make a variable.

Re: Guess what output, and tell me why?

cadinfo10-Sep-02 16:14

cadinfo

10-Sep-02 16:14

jhwurmbach wrote:
,After the compiler optimization, 'ca' has NO address in memory any more.

but in debug mode or use
cout<<"&ca="<<&ca<<"\t&cb="<<cb<<endl;
you will find address of ca is same to cb, and in debug time the value of ca will change to new value, but when output it return to '200'

Re: Guess what output, and tell me why?

jhwurmbach10-Sep-02 20:31

jhwurmbach

10-Sep-02 20:31

Well, I did look at the assembly-code, after tracing did not reveal why '2400' is changed to '200' in output:

16: cout<<"ca="<<ca<<"\tcb="<<cb<<endl;
004017BE push offset @ILT+195(std::endl) (004010c8)
004017C3 mov edx,dword ptr [ebp-8]
004017C6 mov eax,dword ptr [edx]
004017C8 push eax
004017C9 push offset string "\tcb=" (0046e020)
004017CE push 0C8h
004017D3 push offset string "ca=" (0046e01c)
004017D8 push offset std::cout (0047c0c0)
004017DD call @ILT+640(std::operator<<) (00401285)
004017E2 add esp,8
004017E5 mov ecx,eax
004017E7 call @ILT+250(std::basic_ostream<char,std::char_traits<char> >::operator<< ) (004010ff)

At address 004017CE you see how the code inserts the '200' (0C8h) into the output stream and does not access the variable at [ebp-4].

Some sort of optimisation, even in debug mode.
But you can't blame the compiler, after all you *promised* that 'ca' would not change!

how to copy file from dir1 to dir2 in code

ns9-Sep-02 12:20

9-Sep-02 12:20

I have an MFC MDI App. In this I want to copy a bmp from Folder1 into folder2 .How does one do this?

Thanks,
ns

Re: how to copy file from dir1 to dir2 in code

Anders Molin9-Sep-02 12:27

Anders Molin

9-Sep-02 12:27

You could use CopyFile(), look it up in MSDN...

- Anders

Money talks, but all mine ever says is "Goodbye!"

Re: how to copy file from dir1 to dir2 in code

Anonymous9-Sep-02 14:07

Anonymous

9-Sep-02 14:07

SHFileOperation could find some use as well

Location of entry in database -help!ADO

ns9-Sep-02 12:05

9-Sep-02 12:05

I created a new database using ADOX. When I go to add ecords to it, they are added haphazardly, not in order. THe latest one might be in the middle somewhere...

How do I ensure that they get added in order?
Heres my code:

	try
	{

		ADO::_RecordsetPtr rsBlob (__uuidof(ADO::Recordset) );

		m_pCommand->CommandText="SELECT * FROM tblTest" ;  

		rsBlob->CursorLocation = ADO::adUseClient;
		rsBlob->Open ((IDispatch *) m_pCommand, vtMissing, ADO::adOpenKeyset,
							ADO::adLockOptimistic, -1);

		
		rsBlob->AddNew();
		rsBlob->Fields->Item["A_Image"]->Value = bstrFile;//strmBlob->Read(adReadAll);

///////////////////////////////////////////////////////////////////////////////



		char* charID = new char[strID.GetLength()+1];

		strcpy(charID, strID);

//		AfxMessageBox(charID);

		rsBlob->Fields->Item["MINE_TYPE"]->Value = charID;

		delete[] charID;



		}

Thanks for helping,
ns

Re: Location of entry in database -help!ADO

Pavel Klocek10-Sep-02 3:20

Pavel Klocek

10-Sep-02 3:20

The SQL database does not guarantees, that it stores records in particular order (even if it often does). It's by design. The order of returned records is defined by the ORDER BY clause of SELECT query.

Pavel
Sonork 100.15206

Question About Classes

Nick Parker9-Sep-02 12:02

Nick Parker

9-Sep-02 12:02

Can someone give me a practical example/reason of why classes can contain static member functions, aside from data encapsulation I'm not sure I see their purpose. We were talking about them today in a class that I have and my professor couldn't give me any specific reason as to why we have this. Any ideas would be great as I am just a little curious (aside from those that say "So you can call method X without object instantiation" Smile | :)

). Thanks.

Nick Parker

Re: Question About Classes

Christian Graus9-Sep-02 12:27

Christian Graus

9-Sep-02 12:27

I am writing a wrapper for XML in C# at the moment, and one thing that takes a few lines of code normally is to take a node and return the text value, if any, associated with it. node.text simply won't do the job well. By making the function GetNodeValue static, I am able to call it if I have a node kicking around but I don't have an instance of my class. The class essentially becomes a namespace that contains functions which I may have a use for even if I don't have an instance of the class at that point in time, so it saves me building the object needlessly.

Christian

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Cats, and most other animals apart from mad cows can write fully functional vb code. - Simon Walton - 6-Aug-2002

Re: Question About Classes

Nick Parker10-Sep-02 2:58

Nick Parker

10-Sep-02 2:58

Gotcha, I think that pretty much explains it. Smile | :)

Nick Parker

Re: Question About Classes

jparsons10-Sep-02 3:05

jparsons

10-Sep-02 3:05

One of the good uses I've found for static members is factory like functions. If I have a class that I dont' want anybody but me to be able to instanciate I make all of hte constructors private. Then I allow creation through static member functions. This comes in handy sometimes especially in other languages such as C# and Java

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Re: Question About Classes

Pavel Klocek10-Sep-02 3:23

Pavel Klocek

10-Sep-02 3:23

Sometimes you need a class attribute, which is shared between all instances of the class.

Pavel
Sonork 100.15206

Re: Question About Classes

Nick Parker10-Sep-02 7:42

Nick Parker

10-Sep-02 7:42

Pavel Klocek wrote:
Sometimes you need a class attribute, which is shared between all instances of the class.

Could you elaborate?

Nick Parker

Can I include like this #include "C:/1.prv"?

ooosawaddee39-Sep-02 11:54

ooosawaddee3

9-Sep-02 11:54

If I have the data in 1.prv and I want embed that data in program while compile.
Can I include like this #include "C:/1.prv"?

Thank you.

Re: Can I include like this #include "C:/1.prv"?

Christian Graus9-Sep-02 12:28

Christian Graus

9-Sep-02 12:28

Dunno - have you tried ?

Christian

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Cats, and most other animals apart from mad cows can write fully functional vb code. - Simon Walton - 6-Aug-2002

GetDocument() for CDialog?

Brad Jennings9-Sep-02 11:12

Brad Jennings

9-Sep-02 11:12

hey all. I am working on a single document MFC program and currently have a problem. Under a CFormView document, there is the GetDocument function. Is there any way to use this function or get the same effect in a CDialog document? Any help is appreciated. Thanks.

Brad Jennings

Re: GetDocument() for CDialog?

Joaquín M López Muñoz9-Sep-02 11:25

Joaquín M López Muñoz

9-Sep-02 11:25

CYourDoc *pDoc = (CYourDoc *)(((CFrameWnd *)AfxGetMainWnd())->GetActiveView()->GetDocument());

I guess this is what you're after.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

mem_fun & stl question

Jurgen9-Sep-02 11:00

Jurgen

9-Sep-02 11:00

Hi,

I have a vector with pointers to an object. Now for each object I need to call a function Update(float fTime). Now when I write something like this:

for_each(...begin(), ...end(), mem_fun1(CActor::Update(fTime));

fTime is a valid floating point value in the method which calls this algorithm. This does not compile! I tried a variety of alternatives but none compile. Any suggestion on how to compile this?

Jurgen

Re: mem_fun & stl question

Joaquín M López Muñoz9-Sep-02 11:07

Joaquín M López Muñoz

9-Sep-02 11:07

Try with

for_each(...begin(), ...end(), bind2nd(mem_fun(CActor::Update),fTime));

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

CMonthCalCtrl bug?

Deian9-Sep-02 10:55

Deian

9-Sep-02 10:55

Is there anyone that knows why the following piece of code does not work as it's supposed to?

void CStomGraphDlg::OnSelectMonthcalendar(NMHDR* pNMHDR, LRESULT* pResult)
{
COleDateTime dtSel;

if(m_ctlMonthCalendar.GetCurSel(dtSel)!=0)
{
MessageBox(dtSel.Format("%x"));
// set current selection
GetDlgItem(IDC_STATIC_SEL)->SetWindowText(dtSel.Format(_T("%x")));
}
else
{
MessageBox(_T("Error getting current selection"), _T("Error"), MB_OK|MB_ICONERROR);
}
*pResult = 0;
}

It is supposed to return the date selection in COleDateTime format but the only time it works is after the program has just started, and you select the current date. After changing the selection it crashes and returns invalid date format or something. GetCurSel should return the selection date, right?

Any help appreciated,

Mad | :mad:

Deian

Re: CMonthCalCtrl bug?

adamUK9-Sep-02 12:40

adamUK

9-Sep-02 12:40

Deian,

Have a look at this Same problem I perhaps? Only way I could get round it was with GetCurSel( LPSYSTEMTIME pDateTime ) which seemed to return the right result.

Adam.

"I spent a lot of my money on booze, birds and fast cars. The rest I just squandered"
George Best.

Re: CMonthCalCtrl bug?

Deian10-Sep-02 4:19

Deian

10-Sep-02 4:19

Thanks, I will try that solution Smile | :)

))

Greetings,

Deian

Opening Access 2000 database from CD !!!

Hadi Rezaee9-Sep-02 10:32

Hadi Rezaee

9-Sep-02 10:32

Hello there,
I run my program from CD, when my program wants to open the database from CD ... my program crashes Confused | :confused:

I think it's for strange file( .LDB Suspicious | :suss:

) because the database can not make .LDB file beside the access database !

How can i change the .LDB path ?????

Please help me !!!

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

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