Re: Please help with CString to float. - C / C++ / MFC Discussion Boards

Jochum Wittebrood10-Oct-04 11:07

10-Oct-04 11:07

I should also say i've tried: sscanf(CString,"%f",&float) which from what I have read on the web should be able to take CStrings but the compiler (MS Emmbedded visual C++ 3.0) tells me: cannot convert parameter 1 from 'class CString' to 'const char *'" so i've tried other ways to convert CString to LPTSTR and char[102] but i'm stuck. I can't think of what else to try. please help.

In VB all I used was something like: float = CCur (string)
I'm sure its not all the had in C++ but it seems to have me beat!

Thanks in Advance.
Jochum Wittebrood.

Re: Please help with CString to float.

Christian Graus10-Oct-04 11:54

Christian Graus

10-Oct-04 11:54

CString has a method to return the underlying char*, which you can then pass into atof. From memory, it's something like LockString, and you need to call a corresponding Unlock method when you've used the char * for whatever dastardly deed you intend. std::string has the c_str() function which does much the same thing. Sorry, it's too long since I lived in MFC land, I don't know the specific function you want. Hopefully this is enough to push you in the right direction Smile | :)

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Re: Please help with CString to float.

Jochum Wittebrood10-Oct-04 14:32

Jochum Wittebrood

10-Oct-04 14:32

I've had a look through the help docs for functions like that, but I can't find anything that I can get working. I can't find anything on LockString or c_str() maybe i'm not looking in the right places... It shouldn't be this hard should it?

Jochum

Re: Please help with CString to float.

Christian Graus10-Oct-04 14:41

Christian Graus

10-Oct-04 14:41

Jochum Wittebrood wrote:
It shouldn't be this hard should it?

WElcome to MFC....

The methods are GetBuffer and ReleaseBuffer.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Re: Please help with CString to float.

Michael Dunn10-Oct-04 14:49

Michael Dunn

10-Oct-04 14:49

CString s = _T("123.456");
double d = _ttof(s);

--Mike--
Personal stuff:: Ericahist | Homepage
Shareware stuff:: 1ClickPicGrabber | RightClick-Encrypt
CP stuff:: CP SearchBar v2.0.2 | C++ Forum FAQ
----
Wizard needs food, badly!

Re: Please help with CString to float.

toxcct10-Oct-04 21:00

toxcct

10-Oct-04 21:00

simple mathematic operations you say ?
look at this[^]

TOXCCT >>> GEII power

Re: Please help with CString to float.

callisthenes11-Oct-04 3:57

callisthenes

11-Oct-04 3:57

Use the generic C Runtime function _tstof().

See MSDN for more info...

Hope this helps...

Mike

Re: Please help with CString to float.

Jochum Wittebrood12-Oct-04 12:43

Jochum Wittebrood

12-Oct-04 12:43

Thanks for all your help guys, but I tried all the functions that you suggested and they all require 'const char' where the CString seems to be 'unsigned short'. The compiler always gives me convertion errors...

It must be my VB background but I can't seem to get my head around this, while people must use it in code all the time. Does anyone have a small snippit of code to show me how they do it?

This is what I've got...

int ListIndex;
CString WorkingStr;
CString TempStr;
float TAG;

CListBox * List1=(CListBox *)GetDlgItem(IDC_LIST1);

ListIndex = List1->GetCurSel();

List1->GetText(ListIndex,WorkingStr);

TempStr = WorkingStr.Mid(54,8);

TAG = atof(TempStr);

So we know that last line is the problem, but what can I do to fix it?

Thanks for your help.

Jochum

Runtime ComboBox Question

otrcomm10-Oct-04 9:04

otrcomm

10-Oct-04 9:04

Hello,

I know how to change the dropdown width of a combobox during runtime, but does anyone know how to change the width of the actual combobox at runtime?

Thanks,
Murrah Boswell

Re: Runtime ComboBox Question

Antti Keskinen10-Oct-04 9:23

Antti Keskinen

10-Oct-04 9:23

The combo box is the actual control, and the drop-down list box is a child of the combo box.
- To set the width of the list box, send a CB_SETDROPPEDWIDTH message (Win32) or call CComboBox::SetDroppedWidth (MFC).
- To set the width of the combo box control, call SetWindowPos (Win32) or CWnd::SetWindowPos (MFC).

Hope this helps you out.

-Antti Keskinen

----------------------------------------------
The definition of impossible is strictly dependant
on what we think is possible.

Re: Runtime ComboBox Question

otrcomm10-Oct-04 12:03

otrcomm

10-Oct-04 12:03

Thanks for the replay,

How do I get the CWnd handle of my ComboBox?

Murrah Boswell

Re: Runtime ComboBox Question - Never Mind

otrcomm10-Oct-04 12:56

otrcomm

10-Oct-04 12:56

Disregard CWnd question, I figured it out!

Thanks for your help,
Murrah Boswell

Re: Runtime ComboBox Question

toxcct10-Oct-04 21:10

toxcct

10-Oct-04 21:10

GetDlgItem(MY_COMBO)

TOXCCT >>> GEII power

How l

lordmickel10-Oct-04 8:48

lordmickel

10-Oct-04 8:48

Hi, I've created a linked list and in my C++ source file I'm creating objects and passing them to a linked list in a loop. I want to loop over the linked list to show that the values are actually in the list. How would I do this?

I've uploaded all the code here if you want to take a look: http://www.hostmaster-x.co.uk/c++/

Thanks in advance for any help.

Cheers,

lordmickel Confused | :confused:

Re: How l

Christian Graus10-Oct-04 8:54

Christian Graus

10-Oct-04 8:54

If this is not homework, why are you not just using the list class included in C++ ?

Otherwise, just grab the first item, and keep stepping through the list, printing out each item as you go, or whatever else your homework requires. The code you've commented out looks like it should work, if your list is working.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Re: How l

lordmickel10-Oct-04 9:21

lordmickel

10-Oct-04 9:21

Christian, thank you for your reply. This is homework - kind of. I'm not taking classes as such, just dabbling a little. From what you have said it would seem that the list isn't working correctly because when I uncomment the code I get the following output:

Please enter the driver's name then press enter:
driver1
name = driver1
driver2
name = driver2
driver3
name = driver3
name 1:

name 2:

name 1:

name 2:

Press any key to continue

Any ideas what the problem could be?

Cheers again,

lordmickel

Re: How l

Christian Graus10-Oct-04 9:30

Christian Graus

10-Oct-04 9:30

lordmickel wrote:
This is homework - kind of. I'm not taking classes as such, just dabbling a little.

Cool - I applaud that you're writing your own list then. Once it works, you'll understand how they work, and you should then use the STL exclusively Smile | :)

What happens when you step through the code in the debugger ? Are your values getting stored correctly in the list ? What about the pointer values as you step through, where do they go ?

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Re: How l

lordmickel11-Oct-04 7:59

lordmickel

11-Oct-04 7:59

Thank you, thank you! Smile | :)

........ I'm not really familiar with stepping through the code, MS VC++ doesn't seem to be too helpful - or perhaps its just me. Unfortunately I can't really answer any of your questions exactly.

When I ran the debugger, the command prompt popped up and began running the program. When it had finished it produced this:

Loaded 'ntdll.dll', no matching symbolic information found.
Loaded 'C:\WINDOWS\system32\kernel32.dll', no matching symbolic information found.
The thread 0xF9C has exited with code 0 (0x0).
The program 'C:\Program Files\Microsoft Visual Studio\MyProjects\text_class\Debug\text_class.exe' has exited with code 0 (0x0).

Is there a better, more user friendly compiler that I could use that would be able to step through the code properly? I can't seem to get VC++ to do it Frown | :(

Thanks again,

lordmickel Smile | :)

Re: How l

Christian Graus11-Oct-04 10:19

Christian Graus

11-Oct-04 10:19

lordmickel wrote:
Is there a better, more user friendly compiler that I could use

No.

lordmickel wrote:
that would be able to step through the code properly? I

The problem is not the compiler Smile | :)

Use F9 to set breakpoints ( they look like a big black circle on the left margin, make sure you're building a debug version and hit F5. Then VC++ will stop at the breakpoint and allow you to step through the code, set and check variable values, etc.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Re: How l

Antti Keskinen10-Oct-04 8:56

Antti Keskinen

10-Oct-04 8:56

If you need to 'prove' that certain elements (an element of a list contains a value and a pointer to the next element) are members of a list, then the most effective way is to start from the header element and print the value of the 'next' pointer, which is the address of the next element. Then you would move into the next element, print it's address (which resolves to the same as the 'next' pointer on the previous cell), and print the value of this new element's 'next' pointer and move on again, repeating the process.

This will bring forth an effective way to prove that certain elements are linked to each other. It will not work for circularly linked lists, because the loop would never end. For a non-circular list, the last 'next' pointer is a NULL value.

However, I see no reason in 'proving' that the elements are members of a list. Why would anyone need to do such ? Isn't it enough if the list fills it's purpose, whatever that purpose might be ?

-Antti Keskinen

----------------------------------------------
The definition of impossible is strictly dependant
on what we think is possible.

Re: How l

lordmickel10-Oct-04 9:23

lordmickel

10-Oct-04 9:23

Antti, thank you for your reply. I had set something like that up in my classes but something isn't working correctly. I'm just doing this to prove that the list works - which at the moment it doesn't. Thanks for the circular linked list tip.

Thanks again,

lordmickel

Re: How l

Paul Ranson11-Oct-04 10:55

Paul Ranson

11-Oct-04 10:55

Your first problem is that you are not storing valid pointers in your list. Try replacing the load code with,

details * driver = new details ;
driver->enter_driver_name();
output.DisplayDriverName(driver->get_name());
list.add_driver(driver);

And to print the contents try,

details* pDriver = list.getFirstDriver();
while ( pDriver )
{
   cout << "name: " << pDriver->get_name() << "\n" << endl;
   pDriver = list.getNextDriver () ;
}

Note I haven't suggested changed anything in your details or list classes which are basically working... Although you haven't made any attempt to manage memory, a 'package' should probably be able to delete a 'details' and a 'driver_list' should probably have a destructor that deletes all the packages.

Paul

Re: How l

lordmickel13-Dec-04 10:41

lordmickel

13-Dec-04 10:41

Paul, please forgive me for the extremely late reply. I've changed the code and it works perfectly, thank you so much for your very helpful reply!

Thank you,

lordmickel Big Grin | :-D

system info

Lanre Ogunkola10-Oct-04 6:35

Lanre Ogunkola

10-Oct-04 6:35

Does anyone have ideas on how i can retrieve the following system information:
1. processor serial #
2. hard-disk serial #

Thanks

larry_larry

Re: system info

Ravi Bhavnani10-Oct-04 7:09

Ravi Bhavnani

10-Oct-04 7:09

GetVolumeInformation() will get you a disk's serial number.

/ravi

My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.