C / C++ / MFC

Use of string class in c++

19-Feb-20 2:51

Have a look at this competitors page voip - Microsip softphone build problem (cannot open file 'hid.lib') - Stack Overflow[^].

Awantika Singh14-Feb-20 21:26

Awantika Singh

14-Feb-20 21:26

My C++ compiler is not accepting string as a predefined class. No objects of string class could be created.

Victor Nijegorodov14-Feb-20 21:35

Victor Nijegorodov

14-Feb-20 21:35

Do you mean the std::string?
Did you add the
#include <string>

Stephane Capo14-Feb-20 21:38

Stephane Capo

14-Feb-20 21:38

Hello,

some more details would be helpful!

Do you mean std::string ? If this is the case did you include <string> ? :

#include <string>

then use std::string :

std::string astring("a string");

Awantika Singh15-Feb-20 4:27

Awantika Singh

15-Feb-20 4:27

I've included the header file but "using namespace std" this line is also not working.

Richard MacCutchan15-Feb-20 5:06

15-Feb-20 5:06

Quote:
not working.

What does that mean? Generally speaking: nothing.

Please do not expect us to guess what you are doing. Edit your question, show the code you are using, the exact error message that is produced, and which line of code it occurs on.

Stephane Capo15-Feb-20 21:52

Stephane Capo

15-Feb-20 21:52

I agree with other messages, we can not guess everything.

My best guess is that you are compiling a C file? (not C++)...

k505416-Feb-20 3:30

k5054

16-Feb-20 3:30

Or, he could be using an ancient version of C++, like maybe Borland Turbo C++, that doesn't understand namespaces.

Richard MacCutchan16-Feb-20 4:58

16-Feb-20 4:58

But of course, "not working" could mean anything at all.

CPallini16-Feb-20 7:28

16-Feb-20 7:28

The following code should compile (and run) fine in a decent (i.e. reasonable recent) compiler

C++

#include <iostream>
using namespace std;

int main()
{
  const string greetings = "Hello world!";
  cout << greetings << endl;
}

Stefan_Lang16-Feb-20 22:43

Stefan_Lang

16-Feb-20 22:43

Try adding #include <string> Wink | ;)

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

CPallini16-Feb-20 23:02

VfW Saving Compression Options

16-Feb-20 23:02

There's no need, actually.

Member 1305023114-Feb-20 5:35

14-Feb-20 5:35

hi!
i wrote a very simple app to capture videos with VfW.

HWND hwnd = capCreateCaptureWindow ("MyWindow", WS_CHILD | WS_VISIBLE , 0, 0, 160, 120, hwndParent, nID);
capDriverConnect (hWndC, 0);
capDlgVideoCompression(hwnd); // this displays the compression settings dialog
capCaptureSequence (hwnd);

does anyone know how to store the compression settings to reuse them?
is there any possibility to access the internal data of the capture window?
thanks in advance
-arni

Richard MacCutchan14-Feb-20 6:01

14-Feb-20 6:01

Yes, but it depends how the information is stored by the library functions. The documentation should help.

Member 1305023114-Feb-20 11:58

14-Feb-20 11:58

Thanks for the reply...you are right - that's the question! the documentation doesn't say anything about that.

Richard MacCutchan14-Feb-20 22:28

14-Feb-20 22:28

How are these values set in the first place? And, surely if you can display them then you can save the results somewhere.

Member 1305023114-Feb-20 23:36

14-Feb-20 23:36

the call to:

capDlgVideoCompression(hwnd);

displays a dialog to choose compression an parameters, and after "OK" they are stored somewhere (in the hwnd?) this process does work for the current session, but when i restart my app everything is gone. none of the structures (CAPDRIVERCAPS,CAPINFOCHUNK,CAPSTATUS,CAPTUREPARMS,etc.) gives me valid information about the chosen compression. what i need is the COMPVARS or AVICOMPRESSIONOPTIONS structure, but to access these seems to be a completely different approach.
tia.
-arno

Richard MacCutchan14-Feb-20 23:53

14-Feb-20 23:53

The HWND object only exists for the life of the application, so any values stored inside it will be lost when the application terminates. You will need to save all the values yourself in some permanent storage area. See Where should I store my data?[^]; it's written for .NET but can easily be adapted to a Win32 app.

Member 1305023116-Feb-20 1:39

16-Feb-20 1:39

ok, i know that my classes and variables won't survive - the question was not how to SAVE the data, it's how to ACCESS it!
thanks richard.
anyone else has any idea?

jeron117-Feb-20 4:00

jeron1

17-Feb-20 4:00

Quote:
the question was not how to SAVE the data,

from the OP

Title:
VfW Saving Compression Options

Quote:
does anyone know how to store the compression settings to reuse them?

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Member 1305023117-Feb-20 6:35

Change Dir inside CFileDialog

17-Feb-20 6:35

plz read the whole thread! i want to store the settings, that i made in the dialog! i haven't found a way to ACCESS the data/settings programmatically - that was my question.
i know thousands of ways to store/serialize/dump the data.
thank you.

Member 40147611-Feb-20 3:53

Member 401476

11-Feb-20 3:53

Hi everyone, I have a problem in vc6.
In a CFileDialog with 2 configured extensions (eg .Txt and .doc) I want
automatically change directory in my CFileDialog when the extension changes:
when I select the .txt extension I want the CFileDialog in the 'C:\FileTxt' directory,
when instead I select the extension .doc I want the CFileDialog in the directory 'C:\FileDoc'
with the corresponding files list ...
...Can someone help me with some example?
Thank you

I Try, but I'm not sure Smile | :)

)

Re: Change Dir inside CFileDialog

CPallini11-Feb-20 4:56