how to stop run of a program after a message display [modified]

[David Crow]

mrby123 wrote:

I use exit(-1)...

To exit a Windows GUI application? :confused: Not a good choice.

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[mrby123]

When you program suddenly stop, you may want to inform the use what happen. Otherwise, the use feels not good.

[mrby123]

I am running MFC C++ application. Your suggestion is good. I do not know which dialoge box should I use to do such interaction. Thanks again

[Luc Pattyn]

I agree, but then you should choose a more accurate message; maybe "next time you run this program, please enter ...". Although I still think it is rather rude to stop a program just because the interactive user entered something you did not like; you should allow for another chance. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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I only read formatted code with indentation, so please use PRE tags for code snippets.

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[mrby123]

I agree with you, it is better to give user a chance to correct. I wish to find an interactive message box to allow user to inter a correct value for the parameter. Do anyone know how to program an interactive dialogue box? Thanks again

[_Superman_]

Assuming you're using MFC...

If (IDYES == MessageBox(_T("Are you sure you want to quit"), _T("Confirm Exit"), MB_YESNO))
{
PostQuitMessage(0);
}

«_Superman_» I love work. It gives me something to do between weekends.
Microsoft MVP (Visual C++)
Polymorphism in C

[Luc Pattyn]

you may want to implement this pseudo-code:

string s="Please enter a number in the range [a,b]"
for(;;) {
int n=NumericInputBox.Show(s);
if (n==-1) Application.Exit();
if (n>=a && n<=b) break;
s="Sorry, "+n+" is not valid as it is not in the range [a,b]; please try again now (or enter -1 to quit)";
}

:)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

---

I only read formatted code with indentation, so please use PRE tags for code snippets.

---

I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).

---

[mrby123]

Hi Thanks. I will try it. Another Key is to make sure the app can catch the new value entered in the dialogue box. Thanks for any specific instructions.

[Aescleal]

Hi, As you're using an MFC app look up Dialog Data Exchange (DDX) and Dialog Data Validation (DDV). Between the pair of them you can specify allowed ranges for field in a dialog box and give the user a message if they enter something that's out of the range. Out of the box it's a bit clunky but works okay with a bit of tender loving care. So if you've got an edit control with the sampling interval in milliseconds (IDC_SAMPLE_INTERVAL) and you want the user to be able to enter something between 10 and 1000ms, you overide DoDataExchange in your dialogue box class as something like:

void CSampleDlg::DoDataExchange( CDataExchange *pDX )
{
CDialog::DoDataExchange( pDX );

DDX\_Text( pDX, IDC\_SAMPLE\_INTERVAL, sample\_interval\_ );
DDV\_MinMaxInt( pDX, sample\_interval\_, 10, 1000 ); 

}

where sample_interval_ is the data member containing your er, sample interval. If the entered interval isn't between 10 and 1000 MFC displays an message box and lets the user choose to abandon the edit or try again. Cheers, Ash PS: Using exit() in a C++ program can be a bad idea one main reason - destructors aren't run for any objects. If those objects are managing a system global resource then that resource can leak. It can also mean that files aren't flushed and closed properly and may not have the contents you expect. On the other hand exit() can be a quick way to bail out of a misbehaving program with a long shutdown time if that shutdown time is due to a large number of or slow destructors. This is generally regarded as being pretty vile by most C++ experts and only used as a desperate measure.

[KarstenK]

a nice program would check the range and ask for a proper value, before saving the value. -> "Please enter a valid value or quit"

Press F1 for help or google it. Greetings from Germany