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First you don't use VC6 to compiling this code,you can guess the result that will call several Construction and Destruction,at last try to compiling it:
#include iostream.h
class A
{
public:
A()
{
cout<<"Constitution..."<<endl;
}
~A()
{
cout<<"Destruction...."<<endl;
}
};
A foo(A a)
{
return a;
}
int main(int argc, char* argv[])
{
A a;
foo(a);
A b = foo(a);
return 0;
}
why is 1 Counstruction and 5 Destruction ?
thanks for you reply !
Best Reguards !
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Because your code only calls the default constructor once and several times the copy constructor (for which you didn't supply any specific function, so a default will be generated by the compiler).
If you supply a copy constructor the same way you provided a default constructor, you would see that both count matches.
modified on Thursday, November 12, 2009 9:20 AM
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Damn... Cédric-The-Fast-Guy! 
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I stole some monkeys from Rajesh. See, he's not that efficient anymore 
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That's interesting !
thanks for you reply !
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wangningyu wrote: why is 1 Counstruction and 5 Destruction ?
Because default constructor is not the unique constructor, try:
#include <iostream>
using namespace std;
class A
{
public:
A()
{
cout<<"Construction..."<<endl;
}
A(const A & a){cout<<"Copy Construction..."<<endl;}
A & operator=(const A & a){cout<<"Assignment operator..."<<endl;}
~A()
{
cout<<"Destruction...."<<endl;
}
};
A foo(A a)
{
return a;
}
int main(int argc, char* argv[])
{
A a;
foo(a);
A b = foo(a);
return 0;
}
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Ok, so I have been trawling the web to try and find an answer to this, but to no avail.
Basically, I have a DirectShow filter (well 2) which will allow me to configure a Hauppage WinTV USB adapter (though I doubt the specific filter is 100% relevant to answer the question) to use PAL (I) and to set the source as Composite In. So far, I have found ways to display a filter's property page, and to change the settings of a DMO filter, but not enumerate and change the properties of a non DMO source filter.
The reason for needing to do this is that both filter options seem to reset with Windows, meaning that our source becomes NTSC and Tuner In, rather than Pal-I and Composite In. The filters are classed as a Video Capture Source (WinTV HVR-900H Capture) and a WDM Streaming Crossbar Device (WinTV HVR-900H Crossbar), but the ability to change any property of any filter sans a GUI will be a step in the right direction
I am using a .Net wrapper to play with the filter graph through c#, but have limited knowledge of COM interop (thus the wrapper). If you know how to go about this in C++ then I'll do the code rearranging to C#.
What's the easiest method to go about this?
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My project is about data acquisition through USB port and show the data on PC monitor in graph.So I want to implement the queue to keep the data from USB port before send it to show on graph or save it to file.
Does MFC has the class for create or managing the queue?
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I don't really like the MFC container classes (but that's just my opinion), but you could check the std::queue (from the STL).
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Hi all,
I have a combo box. I have created it by declaring CComboBox m_comboBox; at MainFrame class and
if(!m_comboBox.Create(CBS_DROPDOWN | CBS_SORT | WS_VISIBLE |
WS_TABSTOP | WS_VSCROLL, rect, &m_wndToolBar, ID_COMBO))
{
TRACE(_T("Failed to create combo-box\n"));
return FALSE;
}
But the text size very small. How can i increase the size of this text.
Thanks
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Shaheen.India wrote: How can i increase the size of this text.
Have you tried using the combobox's SetFont() method?
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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hello
i need a programme In C how to convert Hexadecimal to decimal and end of programme with @ plz help me
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Hexadecimal and decimal are just different ways of representing the same number, so what's the conversion you're looking for?! 
“Follow your bliss.” – Joseph Campbell
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learn about scanf and printf
--
Si dos montan un caballo, uno debe ir detrás.
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Do you need to convert an hexadecimal representation of a number (i.e. a string, like "5f") to an int value? If the answer is yes then you may try strtol [^], for instance:
int i = strtol("5f", NULL, 16);
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I use the code "Bitmap::FromResource(HINSTANCE, WCHAR)" to load the bmp pic form res and then to fill a rectangle.but can not get a bitmap.
My project is mfc project. so my first question is how to get hte handle of the HINSTANTCE and the second is the wchar parameter, I use "MAKEINTRESOURCE(pResId)" to get he pic name, but get a blank.
and why? whether the gdi+ need more configuration or any other reason.
below is my the whole code
hInstResource = AfxFindResourceHandle(MAKEINTRESOURCE(pResId), RT_BITMAP);
CString src = MAKEINTRESOURCE(pResId);
int strLen = 0;
strLen =src.GetLength();
WCHAR* ch = new WCHAR[strLen];
wcscpy(ch, CT2CW(src));
Bitmap* pBitmap = Bitmap::FromResource(hInstResource, ch);
if(!FindResource(hInstResource, src, RT_BITMAP))
{
AfxMessageBox("Fail load pic!", MB_OK, 0);
}
graphics.DrawImage(pBitmap, 75,35);
TextureBrush* pTextureBrush = new TextureBrush(pBitmap, WrapModeTileFlipY);
graphics.FillRectangle(pTextureBrush, 50,300,200,80);
Color m_penColor(233,100,54);
Pen pen1(m_penColor, 1);
graphics.DrawRectangle(&pen1, 50,300,200,80);
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I have already resolved it
first: hinstance = AfxGetInstanceHandle();
second: FromResource(hInstResource, (LPCWSTR)MAKEINTRESOURCE(pResId));
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how did you do that?
please help
www.logicsims.ir
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Hello community,
i make my own CFileDialogEx derived from CFileDialog, with some new controls on it, but if i run my program on
vista or win7, this new controls are not visible, mean, it is the standard Vista File dialog showed,
but not my own!
How to solve this, so that my CFileDialogEx is showed??
The constructor of my file dialog is called, but newer this OnInitDialog() of my custom file dialog!! 
In the MSDN says that there is a new parameter BOOL bVistaStyle and i set them to FALSE, but i see again the vista standard CFileDialog, not my own!!
Does any one have a idea how to solve this, so i can use my custom CFileDialogEx(derived from CFileDialog)!?
I hope its understandably what i have wrote
In XP is all there, my complete CFileDialogEx!
thanks for any help!
Arrin
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I've used CFileDialog with extra UI (extra dialog) attached to it, and had to use the new bVistaStyle flag to make it work on Vista; the constructor gets called, as well as the OnInitDialog.
class MyFileDialog: public CFileDialog
{
DECLARE_DYNAMIC(MyFileDialog)
};
MyFileDialog::MyFileDialog(LPCTSTR lpszFilter , LPCTSTR lpszDefExt, LPCTSTR lpszFileName, CWnd* pParentWnd) :
CFileDialog(TRUE, lpszDefExt, lpszFileName,
OFN_ALLOWMULTISELECT | OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT | OFN_SHOWHELP | OFN_EXPLORER | OFN_ENABLETEMPLATE , lpszFilter, pParentWnd, 0, <code>FALSE</code>)
{
SetTemplate(0,IDD_MYCUSTOM_DIALOG);
}
I don't think we do any other initializations for the application.
Can you try it with a simple barebone project ?
good luck.
Max.
This signature was proudly tested on animals.
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Hi,
thanx for answer, and i have a own dialog with controls that i show bottom of this standard CFileDialog controls, bottom of combobox of file types.
And the constructor gets called too, but not the OnInitDialog() of my custom dialog(its a modeless dialog as parent), i work on XP system!
I try with SetTemplate()!
regards
Arrin
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Hi,
SetTemplate() dont works
any other idea??
regards
Arrin
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Hi,
I want to display one scrollbar in my view class.
So i created the scrollbar in OnCreate() of view class.
void CTrendView::OnCreate(LPCREATESTRUCT l)
{
CView::OnCreate (l);
HScroll.Create(SBS_HORZ | SBS_TOPALIGN | WS_CHILD | WS_VISIBLE, CRect( 10,10,200,15), this, 1);
}
I declared HScroll in .h file
CScrollBar HScroll;
But the scrollbar doesnot get displayed in my view.
Did i miss anything?
Anu
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If your view class is drived from CView, replace all CView with CScrollView
then you can use scrollbars easily!
www.logicsims.ir
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