Using TextOut() to display a number

This is a discussion on Using TextOut() to display a number within the Windows Programming forums, part of the Platform Specific Boards category; So, I want to use the TextOut function to display an integer in my window. Here`s a piece of my ...

  1. #1
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    Question Using TextOut() to display a number

    So, I want to use the TextOut function to display an integer in my window.

    Here`s a piece of my code :

    Code:
    LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
    {
    	int wmId, wmEvent;
    	PAINTSTRUCT ps;
    	HDC hdc;
    	int anumber = 100;
    	switch (message)
    	{
    	case WM_COMMAND:
    		wmId    = LOWORD(wParam);
    		wmEvent = HIWORD(wParam);
    		// Parse the menu selections:
    		switch (wmId)
    		{
    		case IDM_ABOUT:
    			DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
    			break;
    		case IDM_EXIT:
    			DestroyWindow(hWnd);
    			break;
    		default:
    			return DefWindowProc(hWnd, message, wParam, lParam);
    		}
    		break;
    	case WM_PAINT:
    		hdc = BeginPaint(hWnd, &ps);
    		TextOut(hdc, 20, 20, L"Here is a number : " + anumber, 22);
    		EndPaint(hWnd, &ps);
    		break;
    	case WM_DESTROY:
    		PostQuitMessage(0);
    		break;
    	default:
    		return DefWindowProc(hWnd, message, wParam, lParam);
    	}
    	return 0;
    }
    I posted only this much because it would have been a waste of room the post the whole code.
    Can anybody help ?

  2. #2
    Guest Sebastiani's Avatar
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    >> TextOut(hdc, 20, 20, L"Here is a number : " + anumber, 22);

    char* + int == char*

    Hint: use ssprintf, et al.

  3. #3
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    Don`t really know what you mean, but isn`t sprintf a function in C (I should have specified that my app is a Win32 C++ GUI-based one.) ? And ... what do you mean by "char* + int == char*" ?
    Last edited by Fujy; 04-02-2010 at 06:53 AM.

  4. #4
    CSharpener vart's Avatar
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    you need to use sprintf (if you use C) or std::stringstream (if you prefer C++) to convert integer to string

    after that you use your current function to output text string
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  5. #5
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    Thanks, works now.

  6. #6
    train spotter
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    Just as a note....

    Any variable declared in the callback has very limited scope (lifetime). Each message that is processed means a new 'copy' of the variable.

    If you want the variable to retain its value for the life of the app (not just for one individual message), use 'static' variables in the callback.

    EDIT: I advise you to use _snprintf() or similar versions. sprintf() may/will crash your app if the resultant string is equal to or exceeds the lenght of the char array.

    Code:
    char szBuf[3]={0};
    int    iNum=123;
    
    sprintf(sBuf, "%d", iNum);// this may crash your app
    
    _snprintf(sBuf, 2, "%d" , iNum); //will only print '12' but will not crash app
    Last edited by novacain; 04-06-2010 at 11:11 PM.
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