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i tried fopen. but this normally used to open a file in a specified format na. i need to open an already created xml file as text file in my program and then i have to read the contents. i think fopen cant be used.
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A xml file *is* a text file. There are no problems what so ever to use fopen in order to open a xml file.
(Furthermore, there are no problems opening a binary file either. Just give the correct opening flags, i.e. "rt" for reading a text file, "rb" for reading a binary file).
But there are newer ways of file handling besides using the old C functions. Consider using them.
Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson
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There is no such thing as "opening a file in a specific format".
If there was, then every file format would have a corresponding C-function for opening it.
It's up to you to know the format of the file you're opening. The only thing you can choose from is whether carriage return and line feed combinations should be translated to a single line feed or not. That's the difference between calling fopen with or without the "t" switch in the mode string.
When you've opened the file with fopen you can use fread for reading the contents of the file and fclose for closing it.
Consider using file operations from MFC framework or STL library instead.
"It's supposed to be hard, otherwise anybody could do it!" - selfquote
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deeps_cute wrote: i tried fopen.
Then what was problem ?
deeps_cute wrote: i think fopen cant be used.
It can be.
As mentioned earlier, its a text file. Follow code, you would write for a text file.
deeps_cute wrote: but this normally used to open a file in a specified format na
I think you are mistaking file formats with opening mode. In case of file format like .doc you can use fopen, but you cant read its content to your like because of its format. But thats not issue with .xml file.
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Hello , I am new to VC++ 6.0
I am now developing a MFC dialog based project which will display the signal information in real time and signal strength.
[IMG]http://i176.photobucket.com/albums/w196/well_aisec/image-1.jpg[/IMG]
I need to have 1 analog meter which will constantly update the signal strength value as well as an oscilloscope which will graph the received signal in real time. What I will do to set a Timer which will trigger every 250ms for update and display in Analog meter. At the same time I need to perform
real time graphing for the signal. Meaning the two task is perform asynchronously.
Now here's come the problem.
As the timer is triggered in fast speed, my program seems very laggy to perform both operation in parallel.
May I know what's the problem and solutions?The timer consume a lot of memory space and processing speed? How to improve the program so that it can progress smoothly.
Thanks
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What hardware do you use to collect the signal strength values?
Probably you should have a worker thread waiting on a waitable timer or multimedia timer event. When the timer expires a signal strength value sample is created and assigned a time stamp and put in a queue to be read by the main thread which should be responsible for the presentation.
In cases like this it's usually the data gathering which is time critical. It doesn't matter if the GUI is running 50ms late, the user won't notice anyway but the data would be correct (or as accurate as possible).
"It's supposed to be hard, otherwise anybody could do it!" - selfquote
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The signal strength values comes from a receiver, very much like a radio which will be connected to our serial port.
I am not sure the method you were referring( maybe you can further elaborate in a simple way which i can easily understand?). What I did was my program will be collect signal strength values at the predefined frequency. As the signal strength value of a fixed frequency keep on changes, I created a timer with 250ms time interval to read and update the display. This timer will trigger an event to collect signal strength and update the meter
-- modified at 11:05 Tuesday 6th February, 2007
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Take a look at these[^] articles.
They are aimed at game developers and outline some of the timing issues related to running games at the same speed on various PC's. I feel they relate quite closely to what you are trying to do.
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Your main problem is that the application slow and inresponsive, right?
Is your application multithreaded?
How do you interface with the serial port?
Does the receiver require you to request each sample, or is it sent automatically?
Are you using overlapped I/O? If you're not, then each call to ::ReadFile() will "hang" the application until something is received if the call is made from the primary thread.
There's a fairly large risk that it's the serial communication part that's causing you troubles. Have a look at Joe Newcomer's article on serial communication and see if that helps: clickety[^].
"It's supposed to be hard, otherwise anybody could do it!" - selfquote
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Hi,
I need to do that develop a tree tree control within ListCtrol. How can i do this ?
Can any one suggest me in this ?
Thanks.
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<br />
class base<br />
{<br />
protected:<br />
base() { }<br />
};<br />
<br />
class derived : public base<br />
{<br />
public:<br />
derived() { }<br />
};<br />
<br />
int main()<br />
{<br />
derived* d = new derived; <br />
<br />
}<br />
<br />
Since the base constructor is protected, is creating a derived class in function main() legal? gcc does not give even a warning. I was looking for a means to prevent creation of instances of derived class.
Thomas
modified 29-Aug-18 21:01pm.
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Thomas George wrote: Since the base constructor is protected, is creating a derived class in function main() legal?
Yes, it is.
Thomas George wrote: I was looking for a means to prevent creation of instances of derived class.
Make derived class's c'tor as private, or protected if want to make it inheritable.
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Thank you
modified 29-Aug-18 21:01pm.
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You using public inheritance which gives the subclass access to protected members of the baseclass.
Declare the base class ctor as private, then the inheritance type won't matter.
You could also use protected or private inheritance:
class derived : protected base
class derived : private base ...but then the protection would be the responsability of the subclass which is not so great even if it's syntachtically correct.
"It's supposed to be hard, otherwise anybody could do it!" - selfquote
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Thank you. I will check it out.
modified 29-Aug-18 21:01pm.
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I have got a window divided into 4 parts by means of a splitter. Each part is a CView-derived view which will display a jpeg image.
My problem lies in getting each view to display an image. After I select an image then the window appears transparent and only becomes opaque when I click on the menu bar. The image in the first view remains being displayed but the images in the rest of the views disappear. I have overriden the Paint function so the images should be repainted but this doesn't help.
I am using Visual Studio 2003 on Windows XP SP2.
Any help will be appreciated.
I am the handsome one in the crowd.
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Are all the views displaying the same image?
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No. Each View will display a different image. Each time File Open is selected from the menu then the next view is given an image to display. So eventually all 4 views will have a different image in it.
I am the handsome one in the crowd.
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Are you using Doc/View architecture?
Regardless, each "view" window needs to have access to the image data so it can redraw the image
when necessary (tyically redrawing is done in response to a WM_PAINT message).
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Yes I am using the Doc\View architecture. I have overriden the WM_PAINT and each view then should redraw/paint its own image. I am using CPicture as found here:
http://www.codeproject.com/bitmap/pictureshow.asp[^].
I tried storing the CPicture variable in the CDocument derived class but it seems only one CDocument is created for all 4 views.
I am the handsome one in the crowd.
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Franz Klein wrote: but it seems only one CDocument is created for all 4 views
That's what I was afraid of 
Do you create all 4 views at the start before you have 4 documents?
If so then Doc/View will get in your way a bit since a CView has no way to set a document later.
Maybe create the views with an "empty" document - by empty, I mean with some flag or variable
that indicates the image isn't loaded/available yet. When the image becomes available, use
CDocument::UpdateAllViews() to force a refresh on the views.
In your view classes you can override OnDraw() instead of handling WM_PAINT.
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Hi,
I am making VC++.NET windows application. I made a configuration file (app.config) for my database server settings. But when I am trying to get setting from the file using “ConfigurationSettings” class I am getting NULL in it. Here is my code for that.
NameValueCollection* configCol = ::ConfigurationSettings::AppSettings;
Can I know what is the problem in this?
Thanks in advance,
Priyank
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