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then what will be the following is true for that instance
1)all instances of the parent class will reference one variable and each instance of the child class
would reference its own separate variable
2)all instances of the parent class would reference one variable and all instance of the child class would reference another variable.
3)All instance of the parent and the child classes would reference the same variable.
4)Each instance of the parent and the child classes would reference its own separate variable.
5)None of the above
I want to know answer with some detail, if anybody could have .
Thanks in advance
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Sometimes a little test is better than a thousand words:
(assuming 'parent' is base class and 'child' is derived one)
#include <iostream>
using namespace std;
class A
{
public:
static int alpha;
};
class AA: public A
{
public:
static int alpha;
};
int A::alpha = 1;
int AA::alpha = 5;
void main()
{
int i;
const int N=5;
A a[N];
AA aa[N];
for (i=0; i<n;> {
cout << "a[" << i << "].alpha = " << a[i].alpha << endl;
cout << "aa[" << i << "].alpha = " << aa[i].alpha << endl;
}
}
</iostream>
The output is:
a[0].alpha = 1
aa[0].alpha = 5
a[1].alpha = 1
aa[1].alpha = 5
a[2].alpha = 1
aa[2].alpha = 5
a[3].alpha = 1
aa[3].alpha = 5
a[4].alpha = 1
aa[4].alpha = 5
Personally, I'll bet on point (2). 
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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What is this? Actually writing code to see how C++ works? Why, that's revolutionary.
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
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Joe Woodbury wrote: Why, that's revolutionary.
Yes, since about XVII century.
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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Hello,
I am making a GUI on Visual Studio's (2005) Windows Form Application. I have set the radio buttons to a default value. But, I want to give the user the choice to choose another radio button. But since I have set the value of "Checked" in the event handler of the radio button, right now the default value is the only value that can be chosen (so its fixed). How do I make this changeable?
Thank you in advance,
jazz24
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I'm not all that sure what you are asking.
If you have individual options, which can be on or off independently of each other, then you should be using checkboxes, not radio buttons.
If you have a choice of (eg) three things, only one of which can be selected, radio buttons are good.
They need to be one after each other in the tab order, the first one needs the group bit selected, and all after the first need it deselected.
I would also strongly recommend that the ID numbers are in the same order as the radio buttons.
Then you can use
CheckRadioButton (int nIDFirst, int nIDLast, int nIDSelect);
to programmatically select a radio button, and IsDlgButtonChecked to check whether a radio button is checked or not.
Or DDX_Radio (...) in your CDialog::DoDataExchange (...) function for MFC dialogs.
Iain.
Plz sir... CPallini CPallini abuz drugz, plz plz help urgent.
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My VC6.0 (win 2000 server) stopped responding to F1 and won’t do MSDN search either.
I get an hour glass and File Manager indicates that application is not responding.
I have reinstalled VC 6.0, with SP 6 and reinstalled my MSDN. Any other suggestions?
I am ready to do new install from scratch.
Please, no Vista / VS 200x “upgrades” suggestions , not an option!
Thanks for reading.
Vaclav
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I am trying to create a dll from c++ to be used as a plugin for iTunes. Unfortunately I cannot find any documentation on this. The plugin I am trying to make will be pulling information from iTunes while running and display it in the taskbar as an icon with bubble notifications when the song changes, showing song title etc. Does anyone have any code from plugins they have made in the past? I am very new to this haha.
Thank you
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How can you create a freestanding .exe that does not require the CLR using VS2008. The program is actually ANSI C code, no C++ except for // COMMENTARY.
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Member 4194593 wrote: freestanding .exe
you mean a standalone ?
just statically link the required libraries in your linker settings...
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Member 4194593 wrote: How can you create a freestanding .exe that does not require the CLR using VS2008
In the project settings/Configuration Properties/General, set Common Language Runtime support to
No Common Language Runtime support.
Mark
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Thank you all for the help.
I did not exactly state the true situation, and that was causing me some problems. The project actually linked in another library (also ANSI C only), but the library was build with /MD and this caused multi-defined errors when I tried to use /MT for the base project. I did have the source of the library (fortunately) so I rebuilt it using /MT also, and then the base project compiled correctly. Tested the .EXE on this machine (without VS installed) and it works correctly.
Dave Augustine.
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I have this dialog:
<br />
MYAPP DIALOG 10, 19, 158, 104<br />
STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU<br />
...<br />
BEGIN<br />
...<br />
RADIOBUTTON "1&50%", IDD_Zoom150RB, 16, 10, 32, 10, WS_GROUP | WS_TABSTOP<br />
...<br />
RADIOBUTTON " ", IDD_ZoomSpinRB, 62, 38, 12, 10, WS_TABSTOP<br />
EDITTEXT IDD_ZoomSpinEF, 76, 36, 36, 14, WS_GROUP<br />
...<br />
END<br />
The contents within IDD_ZoomSpinEF editbox, needs to update the IDD_ZoomSpinRB label.
The editbox isn’t associated with the ratio button, thus when the ratio button is selected nothing is read.
How can I associate the editbox with the ratio button?
danginkgo
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danginkgo wrote: How can I associate the editbox with the ratio button?
You can't "associate" them, and have it automatically work.
What you can do is write a EN_CHANGE handler for the edit box, then use SetDlgItemText (ZoomSpinRB, ...) to set the text for the radio button.
I'd be tempted to skip this step though - make the radio button text be blank, and just put the edit box where the radio text would have been. Then when they click on the custom option radio button, read the edit box and use that percentage for whatever you want it for.
Iain.
Plz sir... CPallini CPallini abuz drugz, plz plz help urgent.
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Thank you! Your answer helped me much. I used EN_CHANGE notify and SetDlgItemText().
danginkgo
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Hi there,
I working in VC 6.0, in which I need to polulate the datas in a grid. One of the field may contain values either text or a check box. So how can I implement a column which have only text in some rows and the some rows having check boxes.
Which control should I use, a Data Grid or a List Control?
thanks in advance.
regards,
Rajesh
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Rajesh_Parameswaran wrote: Which control should I use, a Data Grid or a List Control?
It's really up to you, and dependent on your familiarity with each, other app specific details.
I'd also throw in a recomendation for GridCtrl (by our very own C Maunder), and the newer version posted a few months ago. They can take data from a variety of sources, and you can have cells with all sorts of type of data. Checkbox, text, number, colour pickers and (written by me!) progress bars.
Iain.
Plz sir... CPallini CPallini abuz drugz, plz plz help urgent.
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Hey pal! Good to see you again after a while. Where were you? 
Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP
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I've been on a customer's site a lot recently, with internet access on borrowed PCs to check emails, and that's about it.
Rumours of my death have been exagerated.
Sadly, I've only come up for air for only a few days. Then back into hiding...
Iain.
Plz sir... CPallini CPallini abuz drugz, plz plz help urgent.
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Hi There,
Thanks for your response.
One more question: I'm using a ListCtrl with the LVS_EX_CHECKBOXES option. Now I get the checkbox in the first column of the list control. Is it possible to move the check box to any other column in the list control?
thanks in advance.
regards,
Rajesh
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Rajesh_Parameswaran wrote: Is it possible to move the check box to any other column in the list control?
Nope!
Doing a search for LVS_EX_CHECKBOXES, it pointed me at the ListView_GetCheckState "function". A search of the headers showed this a macro wrapper around LVM_GETITEMSTATE. Further investigation shows this affects a list item, not a sub item.
Maybe you could use owner draw, detect mouse clicks, and use hit test messages and write your own subclasses list control that has sub-checks, but I doubt it's worth the effort when you have other controls as I described in my last email.
Iain.
Plz sir... CPallini CPallini abuz drugz, plz plz help urgent.
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I need to write the ASCII (230) in XML content section using MSXML 4.0.
Premise: XML incompatible with third party tool.
Under MSXML I am converting my string to BSTR (wide char), and it end’s up in the XML file back into the ASCII equivalent. Unfortunately it does not work for the accented characters when in the content section of an element. Instead that part of the string stays in wide-char in the xml file.
This is trouble since the XML file is passed to a third party utility that does not support this wide-char, nor the usual mapping like [& eaccent;] nor a XML header indicating UTF-8 or other.
For example:
I save the string:
<Test>Char é</Test>
It will actually be saved as:
<Test>Char Ç</Test>
Where 'Ç' is an example of some accented char (not necessarily 'é').
Note that you must open the XML in binary to see this. Notepad, Visual Studio or XmlPad all display the accented character fine (they detects the wide char, unlike my third party tool).
If I open the XML using a hex editor to replace the 2 characters by the ASCII # 230, the third party tool works fine.
So my question is: How can I force a char-230 (or other bad char) to actually be into the XML file using MSXML 4.0?
My code to create the XML node:
Example: CreateElementNode( myXmlDoc, "Node_Name", "Test é" );
BSTR AsciiToBSTR( LPCTSTR pszFText )
{
BSTR bsText = NULL;
WCHAR *wszURL = NULL;
int wSize = strlen( pszFText );
::MultiByteToWideChar( CP_ACP, 0, pszFText, -1, wszURL, wSize );
bsText = SysAllocString( wszURL );
free( wszURL );
return bsText;
}
MSXML2::IXMLDOMNodePtr CreateElementNode( MSXML2::IXMLDOMDocument2Ptr pXMLDoc, string sName, string sNamespaceURI )
{
MSXML2::IXMLDOMNodePtr node;
BSTR bsName = NULL;
bsName = AsciiToBSTR( sName );
BSTR bsNamespaceURI = NULL;
bsNamespaceURI = AsciiToBSTR( sNamespaceURI );
VARIANT vtype;
vtype.vt = VT_I4;
V_I4( &vtype ) = (int)MSXML2::NODE_ELEMENT;
node = pXMLDoc->createNode( vtype, bsName, bsNamespaceURI );
return node;
}
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I am not trying to nitpick (honestly  ) but there is no char 230 in ASCII. ASCII is a 7-bit encoding and covers only values 0-127.
What you are doing there is basically using the computer's system code page (CP_ACP) which is really a configurable thing, so it may work on your machine, but not on someone else's.
Anyway, Ç is just a UTF-8 representation of your accented character. UTF-8 is the default encoding for XML files. If the 3rd party tool does not recognize UTF-8, you'll need to explicitelly save your XML document in the encoding it will recognize. Also, you'll need to insert the "encoding" instruction accordingly.
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“you'll need to explicitelly save your XML document in the encoding it will recognize”
That’s what I am trying to do, here is an example in binary: (the HEX values are almost random, not sure if they map to an actual accented char).
I have the string: “54, 65, 73, 74, 3a”
The BSTR becomes: “54, 00, 65, 00, 73, 00, 74, 00, 3a, 00”
The XML file opened in Binary is: “54, 65, 73, 74, 00, 3a, 00”
So a mix of ASCII and Wide Char (???). If I replace (manually) “74, 00, 3a, 00” by “74, 3a” then all is fine.
Certainly their must be a way to force the “extended” chars to be re-mapped like all other chars? Is that what you mean by “you'll need to insert the "encoding" instruction accordingly”? But how can I do this thru MSXML?
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