Template function problem - C / C++ / MFC Discussion Boards

Re: Add a CR

samkook2-Mar-06 14:02

samkook

2-Mar-06 14:02

Thanks a lot. I don't know why I didn't think of that.

Re: Add a CR

ThatsAlok2-Mar-06 17:18

ThatsAlok

2-Mar-06 17:18

isn't \n\r work or \r\n ..! OMG | :OMG:

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Re: Add a CR

Michael Dunn2-Mar-06 20:31

Michael Dunn

2-Mar-06 20:31

It depends on what the string will be written to. If it's a text file, use \r\n uness you're going to be using the C I/O functions, in which case use \n and let the CRT change it to \r\n on its own. For multi-line text boxes, use \r\n.
\n\r is never right. Wink | ;)

--Mike--
Visual C++ MVP Cool | :cool:

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Re: Add a CR

ThatsAlok2-Mar-06 20:54

ThatsAlok

2-Mar-06 20:54

Michael Dunn wrote:
\n\r is never right.

Right

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

New to VC++

Chilakaluri2-Mar-06 12:48

Chilakaluri

2-Mar-06 12:48

Can Any one please tell me how can I compile and see the result(on the screen) of the following program using VisualStudio?

include<stdio.h>
main()
{
int i=3;
int*j;
j = &i;

printf("The value of i=%d",*j);

}

Re: New to VC++

Brett Peirce2-Mar-06 13:56

Brett Peirce

2-Mar-06 13:56

Though I personally use streams (cout) for my programs at school, and I am not familiar with the printf() function, If you are using VC++.Net, I think you actually have to put a system("pause"); at the end of your program or it will not remain open long enough for you to see anything... other than that, you'll have to wait for someone else to answer. I hope it helps!

sincerely, Brett Peirce - PolerBear
To err is human; To forgive: divine.

Re: New to VC++

Xing Chen2-Mar-06 14:49

Xing Chen

2-Mar-06 14:49

use getch() function at last,declare in conio.h Smile | :)

Template function problem

Eikthrynir2-Mar-06 11:56

Eikthrynir

2-Mar-06 11:56

Hi! I have a template function problem.
This is what I tried to do:

First, I created a .lib file called writeValue.lib, using this source code:

/* ********************************* */<br />
#include <iostream><br />
<br />
template <class T><br />
void __cdecl writeValue( T value )<br />
{<br />
  std::cout << value << flush;<br />
}<br />
/* ********************************* */

Then, I tried to build a Win32 Console Project, in which I put a single file called main.cpp, containing the following lines:

/* ********************************* */<br />
template <class T><br />
extern void __cdecl writeValue( T value );<br />
<br />
// Link writeValue.lib created above<br />
#pragma comment( lib, "writeValue" )<br />
<br />
int main( void )<br />
{<br />
  writeValue <int> ( 10 );<br />
<br />
  return 0;<br />
}<br />
/* ********************************* */

It compiles, so I get a main.obj, it links writeValue.lib, but I get a link error when I try to use the writeValue( ) function with an integer parameter:

error LNK2019: unresolved external symbol "void __cdecl writeValue<int>(int)" (??$writeValue@H@@YAXH@Z) referenced in function _main

- even though the writeValue( ) function is defined (as a template) in the writeValue.lib file.

All was done in Microsoft Visual Studio .NET Professional 2003.
Can anyone help me with this, please? Thank you!

Re: Template function problem

George L. Jackson2-Mar-06 13:21

George L. Jackson

2-Mar-06 13:21

Template function and classes are created during compile time and instantiation. Thus, your "writeValue" function will not have a definition in your "dll".

You will need to put your template function in a header file. Or, read the following article which involves forcing instantiation: http://www.codeproject.com/cpp/MemberTemplateDLL.asp[^]

Also, this looks promising: http://msdn2.microsoft.com/en-us/library/by56e477(en-US,VS.80).aspx[^]

-- modified at 20:23 Thursday 2nd March, 2006

Handling a double click

Jader892-Mar-06 9:56

Jader89

2-Mar-06 9:56

I want to invoke a certain method when a edit control is double clicked, but i cant seem to find any info on the event handling that i need to do. Any help would be appriacated, thank you.

"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.

Re: Handling a double click

David Crow2-Mar-06 10:06

David Crow

2-Mar-06 10:06

Is this MFC or not?

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: Handling a double click

Jader892-Mar-06 10:09

Jader89

2-Mar-06 10:09

Yea, MFC. Using .NET '02

"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.

Re: Handling a double click

David Crow2-Mar-06 10:33

David Crow

2-Mar-06 10:33

I would instruct you to use ClassWizard, but that does not exist beyond VS v6. I think it has been "replaced" with a properties-type of thing. In any case, You'll need a ON_BN_CLICKED() entry in the dialog's BEGIN_MESSAGE_MAP() method. Don't forget to implement the handler function.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: Handling a double click

Jader892-Mar-06 10:47

Jader89

2-Mar-06 10:47

I tried that. It complies fine, but when its running i tried it out, and it never reachs my method that i attached to it through the ON_BN_CLICKED() method... As of now im just grabbing the cursor on any double click, and having to compare to where my edit controls are, but this seems way to complex for something that i feel should an easier way..

"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.

Re: Handling a double click

David Crow2-Mar-06 10:58

David Crow

2-Mar-06 10:58

See the example here.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

loop processing

ronwurster2-Mar-06 9:51

ronwurster

2-Mar-06 9:51

I have a dialog with several controls in it for several miscellaneous functions. Among them, I created a pushbutton control (function) which, when entered, loops forever processing the following:
opens a file, processes file data, closes the file, sleeps to
allow file access and repeats within the loop.

Once I select the pushbutton to do this, it locks me out from any of the other controls. How can I suspend (etc.) the loop to allow me to tell if another control has been selected and, if so, leave this loop to process the selected control.

Thanks, Ron

Re: loop processing

David Crow2-Mar-06 9:53

David Crow

2-Mar-06 9:53

ronwurster wrote:
opens a file, processes file data, closes the file,

You need to put this code in a worker thread.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: loop processing

ronwurster3-Mar-06 4:33

ronwurster

3-Mar-06 4:33

Thanks David.

getline from file

Peter Charlesworth2-Mar-06 9:34

Peter Charlesworth

2-Mar-06 9:34

hi everyone!

I have a question regarding input and output with files (standard C/C++).
Whenever I use the 'getline' function to get a line from a file and then ask the
program to display that line, it always displays more than a line.
In other words: it doesn't stop 'getting the line' whenever it encounters a
newline.
How can I make sure he reads only one line and no more?
And how can I tell the program to get a specific line, like line n° 34
or the line that follows the words 'myline:' or whatever?

Thanks in advance!

Peter

The program that's supposed to get one line but gets more then that is this one:

<br />
#include <iostream><br />
#include <fstream><br />
#include <string><br />
using namespace std;<br />
<br />
int main () {<br />
  string line;                      // declare a string named 'line'<br />
  ifstream myfile ("example.txt");<br />
  if (myfile.is_open())             // if the file is open, then...<br />
  {<br />
    while (! myfile.eof() )         // while the end of the file is NOT reached...<br />
    {<br />
      getline (myfile,line);        // get a line from the file and put it in the string 'line'<br />
      cout << line << endl;         // output the contents of 'line' to the screen<br />
    }<br />
    myfile.close();                 // close the file   <br />
  }<br />
<br />
  else cout << "Unable to open file";    // if the file can't be opened, display "Unable to open file<br />
<br />
  return 0;                         // close the program<br />
}<br />
<br />

Re: getline from file

David Crow2-Mar-06 9:52

David Crow

2-Mar-06 9:52

Peter Charlesworth wrote:
Whenever I use the 'getline' function to get a line from a file and then ask the
program to display that line, it always displays more than a line.

What do you mean? I tried your code verbatim and it worked fine.

Peter Charlesworth wrote:
In other words: it doesn't stop 'getting the line' whenever it encounters a
newline.

It did for me. What was printed to the console window looked exactly like the contents of the file.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: getline from file

Peter Charlesworth2-Mar-06 9:57

Peter Charlesworth

2-Mar-06 9:57

Well, what I'm trying to accomplish is this:

Suppose a file named "example.txt" has this as content:

<br />
This is line one.<br />
This is the second line.<br />
As you can guess, this is the third line.<br />

And i run the program i mentioned above, then it would output this:

<br />
This is line one.<br />
This is the second line.<br />
As you can guess, this is the third line.<br />

But it's supposed to output this:

<br />
This is line one.<br />

Getline... Get one line and then execute the next piece of code, but instead
it gets the contents of the entire file.

I use Borland C++ 5.5 as my compiler, maybe that my problem is a problem just with my
compiler.

Anyway, thank for responding!

Peter

Re: getline from file

David Crow2-Mar-06 10:05

David Crow

2-Mar-06 10:05

So get rid of the while() loop and see what happens. If what you say is true, then a single call to getline()/cout will display the entire file.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: getline from file

Peter Charlesworth3-Mar-06 3:01

Peter Charlesworth

3-Mar-06 3:01

How could I have overlooked that while() loop?
A very stupid human error...
Well, I'm a novice for something, eh?
Thanks, David!

embedded VC and activesync problem

neodan2-Mar-06 9:27

neodan

2-Mar-06 9:27

Hi. anyone face this problem?

Downloading files
The Microsoft ActiveSync connection server has failed.
Please make sure Microsoft ActiveSync is running and retry the download by Rebuild All or Update Remote Output File(s).
Also make sure that you have selected the correct platform.
Failed downloading.

It seem that this problem was not new when i google this problem but no solution was given. Hope some kind souls will shed some light on this matter. =)

Cheers
dan

ps: btw i using the code from the code project as a sample view
Pocket PC 2003 Filetransfer - The OBEX way
By MBuehrer

Re: embedded VC and activesync problem

Mauro Leggieri2-Mar-06 16:11

Mauro Leggieri

2-Mar-06 16:11

I had a similar problem when my old McAffee antivirus was active. It took a long time to scan the pocket pc (?) and dropped the activesync connection.

Best regards,
Mauro.

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