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Question about initializing strings !

Started by pghTech Sep 12, 2006 at 2:59 PM 0 replies 800+ views

Original Post

Sep 12, 2006 at 2:59 PM

I received the following error ( see below) in VC2005, when I tried to initialize the CString that I added in the header file. But don't received the error when I initialize it the .cpp file. THIS DOESN"T WORK


SourceSnipITView.h

...
...
CString AfxMsg;
AfxMsg = "message goes here";

SourceSnipITView.cpp

...
...
AfxMessageBox(AfxMsg, MB_OKCANCEL);

THIS DOES WORK:



SourceSnipITView.h

public:
    CString AfxMsg;


SourceSnipITView.cpp

AfxMsg = "message goes here"
AfxMessageBox(AfxMsg, MB_OKCANCEL);

I get the following errors if I do the first setup:


------ Build started: Project: SourceSnipIT, Configuration: Debug Win32 ------
Compiling...
SourceSnipITView.cpp
c:\documents and settings\c00smm\my documents\visual studio 2005\projects\sourcesnipit\sourcesnipit\sourcesnipitview.h(74) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
c:\documents and settings\c00smm\my documents\visual studio 2005\projects\sourcesnipit\sourcesnipit\sourcesnipitview.h(74) : error C2864: 'CSourceSnipITView::AfxMsg' : only static const integral data members can be initialized within a class
Generating Code...
Compiling...
SourceSnipIT.cpp
c:\documents and settings\c00smm\my documents\visual studio 2005\projects\sourcesnipit\sourcesnipit\sourcesnipitview.h(74) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
c:\documents and settings\c00smm\my documents\visual studio 2005\projects\sourcesnipit\sourcesnipit\sourcesnipitview.h(74) : error C2864: 'CSourceSnipITView::AfxMsg' : only static const integral data members can be initialized within a class
Generating Code...
Build log was saved at "file://c:\Documents and Settings\c00smm\My Documents\Visual Studio 2005\Projects\SourceSnipIT\SourceSnipIT\Debug\BuildLog.htm"
SourceSnipIT - 4 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Lastly, can anyone tell me where I would find the returned value of AfxMessageBox is? I know it's an int, but thought originally it would be a Sting (i.e MB_OK).

MrAccident

Sep 12, 2006 at 3:12 PM

You're getting those compilation errors because C++ does not allow you to initialize member variables inside a class definition. As the error message says, only static integral constants can be initialized in this manner.

For example, this is allowed:

class Foo{   static const int myConst = 42;   // some other class stuff};

For member variables, though, you must initialize those somewhere in the code of your class; either in a member function, or in a constructor initialization list.

As for AfxMessageBox, it returns an integer. There are a set of #defined macros you can use to check the return value; depending on the style of message box, it could be IDOK, IDCANCEL, IDYES, IDNO, and a couple of others. You can check return values like this:

int return = AfxMessageBox("?", MB_YESNO);if(return == IDYES){   // user clicked "Yes" button}else if(return == IDNO){   // user clicked "No" button}

MB_OK and MB_YESNO are not strings, they are more #defined macros. They're just integers representing message box styles that you can pass to AfxMessageBox() to specify what buttons you want the message box to have.

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