C / C++ / MFC

Re: I'm doing something silly - help!

24-Jul-02 5:25

From the top of my head - you should have at least three character buffer for "aa", "ss" or "dd" - don't forget about trailing null character. However, why on Earth would one mix these manual, low-level, stinky character operations with STL? Can't you just use string& as keyvalue?

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

ns24-Jul-02 5:54

24-Jul-02 5:54

Thanks. You are quite right about CString being a better choice, but I'm simulating a DLL that pre-exists and returns a char *, so I had to venture into the not-so-friendly world of char. Eventaully it replaces my fake function.

Thanks again,
ns

- I meant it didnt compile-got it now!!

ns24-Jul-02 5:24

24-Jul-02 5:24

OOps,I meant it didnt run at all, didnt compile errors were like:

C:\Trainer\Train\Train1\Train1View.cpp(796) : error C2440: '=' : cannot convert from 'char [7]' to 'int'
which didnt clue me in to the fact that I had not declared "value" . I'm sure that error was there too, but I didnt see it buried in all the compiler warnings for STL.

It works now.
Thanks,
ns

Re: I'm doing something silly - help!

Ravi Bhavnani24-Jul-02 7:00

Ravi Bhavnani

24-Jul-02 7:00

(I know I'm not answering your question, but...) You should bracket your code within <pre> and </pre> tags in order to preserve the indentation so that it's easy to read. The new formatting buttons that Chris introduced makes it easy to do this.

Thanks,

/ravi

Let's put "civil" back into "civilization"
http://www.ravib.com
ravib@ravib.com

Re: - I meant it didnt compile-got it now!!

Christian Graus24-Jul-02 12:38

Christian Graus

24-Jul-02 12:38

ns wrote:
I'm sure that error was there too, but I didnt see it buried in all the compiler warnings for STL.

You can get rid of those warnings with a pragma.

Christian

come on all you MS suckups, defend your sugar-daddy now. - Chris Losinger - 11/07/2002

Re: - pragma warning.

ns25-Jul-02 1:34

25-Jul-02 1:34

I found this:

#pragma warning(disable:4786)

I included it in every file that had #include <set> in it. I still got warnings - a ton- and all are 4786. I am reading http://www.codeproject.com/vcpp/stl/stl_without_warnings.asp now. Thanks very much for your response,
ns

How to Integrate a version for DLL

Raphael Kindt24-Jul-02 3:26

Raphael Kindt

24-Jul-02 3:26

I want to integrate a version for my DLL... How to do that???
Thanks in advances

Hello World!!! Smile | :)

from Raphaël

Re: How to Integrate a version for DLL

Ravi Bhavnani24-Jul-02 4:50

Ravi Bhavnani

24-Jul-02 4:50

Add a resource script (.rc) file to the project, then select the "Resources" tab within VC++ and add a version resource.

/ravi

Let's put "civil" back into "civilization"
http://www.ravib.com
ravib@ravib.com

need help in c program

Henry soon24-Jul-02 3:14

Henry soon

24-Jul-02 3:14

I was the beginner of the learner c language now meet some proble instead donot how to apply the colour source in my program so hope can u help me? The project that want to apply in the background text and text that hv the colour.
Thank you.

benjymous24-Jul-02 3:56

benjymous

24-Jul-02 3:56

I'm sorry, but I can't understand what you're trying to ask Frown | :(

--
Help me! I'm turning into a grapefruit!

henry soon24-Jul-02 4:02

henry soon

24-Jul-02 4:02

i want ask how to apply the colour in the c language program while we execute the program that colour will appear at the MS-DOS Prompt

henrysoon24-Jul-02 4:04

henrysoon

24-Jul-02 4:04

i need the colour source code and that function how to use i hv try before that with using the #include <graphics.h> to apply the color for my text and text background color but cannot work

Constructors throwing exceptions cont.

benjymous24-Jul-02 4:35

benjymous

24-Jul-02 4:35

To change colours in a console window use SetConsoleTextAttribute

--
Help me! I'm turning into a grapefruit!

tom7624-Jul-02 3:13

24-Jul-02 3:13

My current code is this

AddPrinterDialog::AddPrinterDialog()
{
try
{
mAddPrinterDialogPointer = new AddPrinterDialog;
}
catch(...)
{
PostMessage( WM_QUIT, 0, 0 );

}
}

BUT what happens if I have an overloaded constructor that initialises data members during construction? My try block won't work will it, as I am using 'new' to implicitly call the default constructor.

How could I change my code so I can construct an object with all data members initialised to ArgumentA that is passed in?

Daniel

Obseve everything, remember more...

Tomasz Sowinski24-Jul-02 3:21

24-Jul-02 3:21

I'm not sure what you're after now. Can't you just use right constructor with new?

m_addPrinterDialogPtr = new AddPrinterDialog("doopa", "zoopa", "koopa", NULL, 3.14);

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

tom7624-Jul-02 4:02

24-Jul-02 4:02

I've just found that the following puts the aplication into an assertion loop.

// Default constructor<br />
AddPrinterDialog::AddPrinterDialog()<br />
{<br />
    try<br />
    {<br />
        mAddPrinterDialogPointer = new AddPrinterDialog;<br />
    }<br />
    catch(...)<br />
    {<br />
<br />
    }<br />
<br />
}

All I want is some code that has a constructor throwing an exception if it fails. It seems I can't use the current code.

That webpage was interesting, but the code was v.confusing. For example

<br />
// Example 1(a): Constructor function-try-block<br />
//<br />
C::C()<br />
try<br />
  : A ( /*...*/ ) // optional initialization list<br />
  , b_( /*...*/ )<br />
{<br />
}<br />
catch( ... )<br />
{<br />
  // We get here if either A::A() or B::B() throws.<br />
<br />
  // If A::A() succeeds and then B::B() throws, the<br />
  // language guarantees that A::~A() will be called<br />
  // to destroy the already-created A base subobject<br />
  // before control reaches this catch block.<br />
}<br />
<br />

is all very well but what if you're NOT inheriting? Or you don't care about parent classes (say you derived from an MFC class).

All I want is a default constructor throwing an exception. But I have no idea how you test for an object's existence, especially inside the default constructor's body as the object won't have been created yet.

Obseve everything, remember more...

Tomasz Sowinski24-Jul-02 4:10

24-Jul-02 4:10

First of all, you have infinite recursion in your construction - I didn't spot this in original post. Why are you keeping pointer to AddPrinterDlg inside AddPrinterDlg?

Second: as the article I've pointed you to said, object doesn't live (and, in fact, have never been born) when exception was thrown during construction. If you expect exceptions coming out of constructor, you should create your object in try/catch block.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

tom7624-Jul-02 4:28

24-Jul-02 4:28

Firstly thanks for your continued support. Much appreciated. I am understanding a bit more now.
The pointer is a member of AddPrinterDlg.

My instructions are that "every constructor that fails shall throw an exception" but I am having problems with this.

From what you say, should I assume that every time I create an object in my .cpp files I should put it in a try block?
Like so:

//... some code...
try
{
if ( !AddPrinterDlg DlgObject )
{
throw 100;
}
}
catch( int i )
{
cout << "Error: " << i << endl;
}

DlgObject.DoModal()

//... more code...

Obseve everything, remember more...

Tomasz Sowinski24-Jul-02 4:34

24-Jul-02 4:34

You should use try/catch when your objects may throw an exception from their constructors (and from other methods as well).

What kind of failures are you expecting in AddPrinterDlg constructor?

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

tom7624-Jul-02 4:51

24-Jul-02 4:51

I'm not expecting any failures whatsoever, but it's got to be in as a safeguard.

So what do I put in the empty constructor body? do I need to put a try and catch block in there or do I just leave it blank?

Obseve everything, remember more...

Tomasz Sowinski24-Jul-02 5:03

24-Jul-02 5:03

tom76 wrote:
So what do I put in the empty constructor body?

Nothing. If your base class constructor throws, you're not going to catch it in constructor body. Standard C++ allows try/catch blocks outside body of the constructor (you could see examples at www.gotw.ca site), but Visual C++ doesn't support that, at least in version 6. Even if you could use try/catch outside of the c'tor body, your only option would be translating caught exception to some other type.

For more info on exceptions, I'd recommend reading "Exceptional C++" by Herb Sutter.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?