C / C++ / MFC

Re: How to use MFC to design an app that can connect 2 types of database

19-Mar-15 22:38

There are no limitations to support different types of databases in one application. The application wizard only prepares the project to support a specific database interface. Support for other interfaces can be added later manually.

My suggestion:
Create two new empty projects with support for different database interfaces. Then choose one as your project and add the necessary definitions from the created source files of the other project by comparing the files.

DHLao19-Mar-15 23:06

DHLao

19-Mar-15 23:06

Thanks for reply.
Since wizard can relief my work. I just think is it possible to select both ODBC and OLEDB by using wizard.
If it is not possible, I have to implement the code myself.
That's hell a lot of work Dead | X|

Re: How to use MFC to design an app that can connect 2 types of database

Jochen Arndt19-Mar-15 23:29

Re: How to use MFC to design an app that can connect 2 types of database

19-Mar-15 23:29

The selection uses radio buttons. So only one can be selected.

You must write the code to access the database anyway. The wizard will not do that. It just prepares your project. Merging two empty projects into one is not much work.

jschell20-Mar-15 13:06

jschell

20-Mar-15 13:06

Note that reading even a trivial excel file in an application can be a difficult task.
Once you have read the data the user interface and writing to a database is easier because there are more sources that one can learn from.

To copy path of selected file or folder

Member 1147315918-Mar-15 7:33

Member 11473159

18-Mar-15 7:33

I added one extra "copy path" option in windows 7 context menu using regedit ...
when I right click on any file and select "copy path" option the path of that file should get copied to txt file

plz help me out ....I m working on one project where I need this...

Re: To copy path of selected file or folder

jeron118-Mar-15 8:11

jeron1

18-Mar-15 8:11

What is the C/C++/MFC question here?

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment

"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst

REPOST

Richard Deeming18-Mar-15 8:37

Richard Deeming

18-Mar-15 8:37

You already asked this question a couple of weeks ago:
"copy path" option in right click context menu using c#[^]

DO NOT post the same question multiple times.

Either follow the article that Sergey linked to[^], or use the built-in "Copy as path" option[^] that I linked to.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

How to fast read excel file, with VC2005

lichengbyd18-Mar-15 2:46

lichengbyd

18-Mar-15 2:46

When read big excel file, it takes many time to read cell one by one.

Jochen Arndt18-Mar-15 3:09

18-Mar-15 3:09

You did not tell us which method you are using to read Excel files.

If you use OLE automation, you should use arrays to read multiple cells at once (e.g. all cells of a row or all cells of muliple rows).

See the MSDN article How to automate Excel from MFC and Visual C++ 2005 or Visual C++ .NET to fill or obtain data in a range using arrays[^].

lichengbyd18-Mar-15 3:50

lichengbyd

18-Mar-15 3:50

I'm Using Library for Office

// Loop through the data and report the contents.
for (int rowCounter = 1; rowCounter <= iRows; rowCounter++) {
for (int colCounter = 1; colCounter <= iCols; colCounter++) {
index[0]=rowCounter;
index[1]=colCounter;
COleVariant vData;
saRet.GetElement(index,vData);
CString szdata(vData);
valueString += szdata;
valueString += "\t";
}
valueString += "\r\n";
}

In this example, it's using loop to read cells, the reading speed is not good.

Jochen Arndt18-Mar-15 4:02

18-Mar-15 4:02

Which library?

lichengbyd wrote:
In this example, it's using loop to read cells, the reading speed is not good.

It is using the loops to extract the values from the safe array. But the data are already in memory of your application. You missed the call that retrieves the data from Excel:

// Get the data.
COleSafeArray saRet(oRange.get_Value(covOptional));

Writing Vector object into a .txt file

lichengbyd18-Mar-15 4:30

lichengbyd

18-Mar-15 4:30

Indeed, thanks for you infomation!

Member 935023718-Mar-15 0:16

18-Mar-15 0:16

Hi all!,

I've been working on a code to develop a tracking game with a haptic device as controller. I use library Chai3D and OpenGL.

I need to save some information of the game during the program execution. And write into a txt file.

I'm attaching part of my code where mentioning vector objects need to be saved:

C++

void updateHaptics(void)
{
    // main haptic simulation loop
    while(simulationRunning)
    {
        // for each device
        
            // read position of haptic devices 1,2
            cVector3d  newPosition1,newPosition2;
			 
			//hapticDevices[i]->getPosition(newPosition);
            hapticDevices[0]->getPosition(newPosition1);
			hapticDevices[1]->getPosition(newPosition2);

            // read orientation of haptic devices 1, 2
            cMatrix3d newRotation1, newRotation2;
            hapticDevices[0]->getRotation(newRotation1);
			hapticDevices[1]->getRotation(newRotation2);

            // update position and orientation of cursors
            cursors[0]->setPos(newPosition1);
			cursors[1]->setPos(newPosition2);
            cursors[0]->setRot(newRotation1);
			cursors[1]->setRot(newRotation2);

            // read linear velocity from devices 1,2
            cVector3d linearVelocity1, linearVelocity2;
            hapticDevices[0]->getLinearVelocity(linearVelocity1);
			hapticDevices[1]->getLinearVelocity(linearVelocity2);

            // update arrow for device 1
            velocityVectors[0]->m_pointA = newPosition1;
            velocityVectors[0]->m_pointB = cAdd(newPosition1, linearVelocity1);
			
			// update arrow for device 2
			velocityVectors[1]->m_pointA = newPosition2;
            velocityVectors[1]->m_pointB = cAdd(newPosition2, linearVelocity2);
			
			
			// Apply a coupled force F1= Kp (X1-X2)
			
			double Kp = 60.0; // [N/m]
			double Kb = 3.0; // [N.s/m]
			
			cVector3d newForce (0,0,0);
            cVector3d coupledForce1 = cMul(Kp, (newPosition1-newPosition2))-(cMul(Kb, (linearVelocity2)));
			newForce.add(coupledForce1);
			hapticDevices[1]->setForce(newForce);// send computed force to haptic device 1

		    
			cVector3d newForce1 (0,0,0);
			cVector3d coupledForce2 = cMul(Kp, (newPosition2-newPosition1))-(cMul(Kb, (linearVelocity1)));
			newForce1.add(coupledForce2);
			hapticDevices[0]->setForce(newForce1);// send computed force to haptic device 0
		
    }
    
    // exit haptics thread
    simulationFinished = true;
}

On the above code I need to save these objects into a file

cVector3d newForce
cVector3d NewForce1

Please help me how to make a provision to save these file effectively into a txt file.

Basically I dont have much idea on saving , writing into files.

Thanks in advance!

Jochen Arndt18-Mar-15 0:46

18-Mar-15 0:46

There is an edit link below your post which should be used rather than posting a new question.

There is also a delete link. Please use that to delete your first question.

To write the elements to a text file, you may open the file using fopen() and then print the elements using fprintf():

C++

FILE *f = fopen(fileName, "wb");
fprintf(f, "%lf %lf %lf\r\n", newForce.x, newForce.y, newForce.z);
fprintf(f, "%lf %lf %lf\r\n", newForce1.x, newForce1.y, newForce1.z);
fclose(f);

Depending on the required accuray it may be necessary to specify the number of significant digits to be printed (see the printf() format specifications).

[EDIT]
The above is for Windows text files. For Unix text files remove the '\r' from the fprintf() format strings.

Member 935023718-Mar-15 1:38

18-Mar-15 1:38

Hey Thank you Jochen!.

Im just wondering how can i make use of a buffer where intitially I can dumb my data..and once the execution is completed writing into a file..do you have a suggestion?.

Jochen Arndt18-Mar-15 1:59

18-Mar-15 1:59

You can do it similar using sprintf() to print to a buffer and then write the buffer to file:

C++

char buffer[128];
char *p = buffer;
int n = sprintf(p, "%lf %lf %lf\r\n", newForce.x, newForce.y, newForce.z);
s += n;
sprintf(p, "%lf %lf %lf\r\n", newForce1.x, newForce1.y, newForce1.z);
FILE *f = fopen(fileName, "wb");
fwrite(buffer, 1, strlen(buffer), f);
fclose(f);

But as you can see this is much more code and it is insecure without checking for buffer overflows (which adds more code).

If you don't need the data to be in text format (e.g. only loaded by your application), it might be better to write the data to a binary file. That solves also the problem of inaccuracies when converting floating point values to text and back again later.
Example:

C++

FILE *f = fopen(fileName, "wb");
fwrite(&newForce.x, sizeof(newForce.x), 1, f);
// Write other items here
fclose(f);

Reading is then done in a similar way:

C++

FILE *f = fopen(fileName, "rb");
fread(&newForce.x, sizeof(newForce.x), 1, f);
// Read other items here
fclose(f);

Member 935023718-Mar-15 5:03

18-Mar-15 5:03

Many thanks Jochen!! Thumbs Up | :thumbsup:

.

I'm planning to use just one file containing information about two forces, something like this:

timestamp newforce(X Y Z) newForce1(X Y Z))

where the values of x,y,z will be in column.

C++

fprintf(pFile, "%lf %lf %lf\r\n %lf %lf %lf\r\n", newForce.x, newForce.y, newForce.z, newForce1.x, newForce1.y, newForce1.z);

do you think it's a right assignment?, I mean how can I write data effectively into the file with proper indentation?

Jochen Arndt18-Mar-15 5:19

18-Mar-15 5:19

You can use the printf format specifiers (see http://www.cplusplus.com/reference/cstdio/printf/[^]).

Using the width specifier, all numbers will have the same width padded with blanks. For proper alignment of the decimal point you should also use the precision specifier and the flag specifier (use a space or minus). The final values to be used depend on the range of your values and the required precision. Assuming a range up to (but excluding) 100 and a precision of 2 fractional digits:
Precision = 2
Width = 1 (sign) + 2 (digits) + 1 (decimal point) + 2 (digits) = 6

Then use the format "% 6.2f" for each value:

fprintf(pFile, "% 6.2f % 6.2f % 6.2f\r\n% 6.2f % 6.2f % 6.2f\r\n", 
    newForce.x, newForce.y, newForce.z, newForce1.x, newForce1.y, newForce1.z);

For the time stamp you can use the strftime()[^] function.

modified 18-Mar-15 13:08pm.

Member 935023718-Mar-15 6:33

18-Mar-15 6:33

I tried as u suggested , but now the data I'm getting is kind of overflowing, I mean it's always generating a data txt file of 1kb!!

Jochen Arndt18-Mar-15 6:59

18-Mar-15 6:59

You may give an example of your data. Inspecting the text file may also give a hint what is going wrong.

[EDIT]
I have replaced the usage of "%lf" by "%f" in my post. But this should make no difference with MS compilers.

modified 18-Mar-15 13:09pm.

Member 935023718-Mar-15 22:32

18-Mar-15 22:32

Hi Jochen,

I'm getting data like this

18832315686612578000000000000000000000000000000000000000000000000000.00 18832315686612578000000000000000000000000000000000000000000000000000.00 18832315686612578000000000000000000000000000000000000000000000000000.00
18832315686612578000000000000000000000000000000000000000000000000000.00 18832315686612578000000000000000000000000000000000000000000000000000.00 18832315686612578000000000000000000000000000000000000000000000000000.00

It's 2 raws of numbers..3,5 lines are continuation of 1st line..ans so 4,6 ..

It's basically limited to 1kb irrespective of the duration of experiment

Jochen Arndt18-Mar-15 22:44

18-Mar-15 22:44

That are quite large numbers. Are they the correct values? If your numbers are in that range, you should use the "%E" format.

Member 935023719-Mar-15 22:27

19-Mar-15 22:27

Hi Jochen,

Now it's working perfectly!. I did a a mistake in closing the file. Thank you so much for your prompt and precise feedback!.

Jochen Arndt19-Mar-15 22:29