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Hello:
I have this interesting problem...
I have to use a c-library that contains a function that is defined as follow:
int func(char * cpData);
I have been using a structure accually a nested structure as follows
struct A
{
char cString;
char cAnotherstring;
}sA;
struct B
{
int iIndex;
float fData[MAXDATA];
}sB;
struct C
{
struct A nA;
struct B nB[8];
}sStream;
I can call this structure with now problems
using func((char *) &sStream);
I wanted to use a vector for the float fData
such as the struct B is as follows:
struct B
{
int iIndex;
vector< float> fData;
} sB;
when I call the function I getting garbaged data.
I do take care of reserving the data size.
In fact I can see that the correct data is there just prior to calling
this legecy function.
Is there a way I can convert somehow to c-array which the function understand
but be able to use the advantage of the vector.
Your speedy reply wiill be vey much appreciated.
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Hy,
Change call to this:
func((char*)&sStream.nA)
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Sorry but the whole structure has to be sent.
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And how you wan't use C++ class vector in C library ? 
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Hello,
The function takes a character array as an argument. Therefore, you cant pass a struct, unless you want to find out how the function accesses the memory...
A better way is to do your own data conversion prior to passing it to the function.
Multiply it by infinity and take it beyond eternity and you'll still have no idea about what I'm talking about.
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I'm sure its simple but I just can't seem to figure out how the get the number I have in a CString object into a float so I can do simple math on it.
I grab a CString from a CListBox, then use CString.MID to strip the string for some number values I want to add tax values to. Thats where I get stuck. Then the plan is to play with the float values and stick them into Static controls as CStrings again which I should be able to do with CString.Format.
I'm sure its just a silly beginer question, but I can't figure it out. Please help!
Jochum Wittebrood
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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.
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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
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
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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
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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
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simple mathematic operations you say ?
look at this[^]
TOXCCT >>> GEII power
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Use the generic C Runtime function _tstof().
See MSDN for more info...
Hope this helps...
Mike
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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
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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
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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.
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Thanks for the replay,
How do I get the CWnd handle of my ComboBox?
Murrah Boswell
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Disregard CWnd question, I figured it out!
Thanks for your help,
Murrah Boswell
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GetDlgItem(MY_COMBO)
TOXCCT >>> GEII power
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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
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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
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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
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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 
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
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Thank you, thank you! ........ 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 
Thanks again,
lordmickel
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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
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
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