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I am defining a vector as a private variable of a class Grid. Class Points has only two instance vars that are all ints. Did I initialize constructor correctly and When writing a destructor for Grid do I need to write a destructor for vector like this: ~vecotr() or with delete or using iterator?
class Grid{
public:
Grid(vector<Points> v) : vector<Points>(3, 0) {};
~Grid() {
~vector<Points>(); }
~Grid() {
delete v_points;
}
~Grid() {
for (vector<Points>::iterator it = v_points.begin(),
vector<Points>::iterator it_end = v_points.end(); it != it_end; it++)
}
private:
vector<Points> v_points;
};
Which option should I use and did I initialize constructor correctly?
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You din't need any of your options. The vector destructor is automatically called by the Grid one. In turn the vector destructor calls the destructor of every object stored.
Try the following code:
#include <iostream>
#include <vector>
using namespace std;
class A
{
public:
~A(){cout << "A dtor" << endl;}
};
class B
{
vector <A> v;
public:
B()
{
A a;
v.push_back(a);
v.push_back(a);
v.push_back(a);
}
};
int main()
{
B b;
}
Veni, vidi, vici.
modified 30-Aug-13 4:24am.
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The vector initialization is not correct. It should be
Grid(vector<points> v) : v_points(v) {};
Also you should consider making the parameter a const reference. This way you avoid one copy operation.
The good thing about pessimism is, that you are always either right or pleasently surprised.
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which initialization is better considering I will definitely have to increase the number of points at runtime? Will option 3 stop me form doing that?
option 1:
private:
vector<Points> const v_points
option 2:
private:
const vector<Points> v_points
option 3:
private:
const vector<Points> const v_points
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None will work for your purpose: the first and second are equivalent, and, if it is syntactically valid at all, so is the third.
The previous comment about a const reference refers to your constructor code, not the member variable declaration. I. e. you should write
Grid(const vector<Points>& v) : v_points(v) {};
instead of
Grid(vector<Points> v) : vector<Points>(3, 0) {};
This will initialize the member variable v_points with the exact same values that are stored in the vector v you pass as a fcuntion parameter.
If you want a constructor that initializes your vector with 3 points, you don't need the parameter v, so you only need:
Grid() : v_points(3) {};
Note that these three points will be initialized by calling the default constructor for your class Point. If that constructor does not initialize it the way you want, you must change the values inside your constructor body like this:
Grid() : v_points(3) {
for (auto it_point = v_points.begin(); it_point != v_points.end(); ++it_point)
*it_point = 0; };
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How to pass array from MFC (dialogbased) to win 32 DLL ?
In MFC application I have read csv file and stored 2nd column into into array(Elastmod)how do I pass that array to win 32 DLL?right now it only takes first element of array not all the eelements.
// MFC File
extern "C" __declspec(dllimport)void CommonBinFrame(char Scanfile[_MAX_PATH],float E[25]);
// read .csv file
CString Token;
CString Separator = _T(",");
int Position = 0;
CString strFilePath = ("C:\\dm1.csv");
CString strText;
CStdioFile readFile;
CFileException fileException;
if (readFile.Open(strFilePath, CFile::modeRead, &fileException))
{
while(readFile.ReadString(strText))
{
float Elastmod[25];
float *P;
P= Elastmod;
int Position = 0;
while(strText.Tokenize(Separator, Position)!="")
{
for(int i=0;i<=24;i++)
{
int Position = 0;
Token = strText.Tokenize(Separator, Position);
Token = strText.Tokenize(Separator, Position);
Elastmod[i] = atof(Token);
readFile.ReadString(strText);
}
}
char Scanfile[_MAX_PATH];
CommonBinFrame(Scanfile,Elastmod); // Here I got full array which i wanted to pass to DLL
}
}
else
{
CString strErrorMsg;
strErrorMsg.Format(_T("Can't open file %s , error : %u"),"C:\\dm1.csv" , fileException.m_cause);
AfxMessageBox(strErrorMsg);
}
readFile.Close();
}
//DLL file
extern "C" __declspec(dllexport)void CommonBinFrame(char Scanfile, float *E);
void CommonBinFrame(char Scanfile, float E[])
{
}
Float E[]= only have 1st array element
Thank you.
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Since Elastmod points to the array, when you pass Elastmod, you ARE passing the whole array.
It looks to me as if the real problem is how do you tell the CommonBinFrame function the size of the array?
Do you have the source code for the DLL?
The difficult we do right away...
...the impossible takes slightly longer.
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//Dll Code
extern "C" __declspec(dllexport)void CommonBinFrame(char Scanfile, float Elstmod[25]);
float Poisson[] = {0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,
char Scanfile[_MAX_PATH]; 0.3};
void CommonBinFrame(char Scanfile, float Elastmod[25])
{
//some code//
new_header_out(Elastmod);
//some code//
}
void new_header_out(float Elastmod[25)
{
//some code//
for(count=0;count
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Well, if the CommonBinFrame function is expecting an array with 25 elements, then I guess all is well.
The difficult we do right away...
...the impossible takes slightly longer.
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peoria123 wrote:
extern "C" __declspec(dllexport)void CommonBinFrame(char Scanfile, float *E);
void CommonBinFrame(char Scanfile, float E[])
{
}
Float E[]= only have 1st array element
I'm not sure what that is supposed to be but it does not look like valid code. You also have a separate issue that your function definition declares its first parameter as a char rather than a char*. It should rather be something like:
extern "C" __declspec(dllexport)void CommonBinFrame(char* Scanfile, float *E);
void CommonBinFrame(char* Scanfile, float *E)
{
printf("%s\n", Scanfile);
for (int i = 0; i < 25; ++i)
{
printf("item[%d]: %6.2f\n", i, E[i]);
}
}
<div class="signature">Veni, vidi, abiit domum</div>
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I have a hierarchy of classes processing serial (COM port) data.
The UI is CpropertyPage ( in main thread) and the port data is retrieved by a COM port thread.
It all works, sort of.
Two “problems” ,related.
I would like to be able to receive error messages from each stage and need to pass the data received back to the CpropertyPage.
I thought that I could use Post/Send messages to do this, but I cannot figure out how to pass the CpropertyPointer “down the line”.
Here is the first working attempt snippet:
In CpropertyPage class :
SendMessage(WM_SERIAL_OUTPUT); // message received in CpropertyPage OK
CString strTest = this->strFrequency; // just checking OK
lResult = pC_SerialMFC->pC_SerialEx->Open(strPort, 0,0,true,this ); // OK
Here is the first “down step” and it fails
LONG C_SerialEx::Open (LPCTSTR lpszDevice, DWORD dwInQueue,
DWORD dwOutQueue, bool fStartListener, void* pointer )
{
TRACE("\nOpen port %s using base class ",lpszDevice ); // Call the base class first
CString strTest = pointer.strFrequency; // compiler error – see below
SendMessage((HWND) pointer, WM_SERIAL_OUTPUT,0,0); // no message received - I did not use Spy to trace where it went
left of '.strFrequency' must have class/struct/union type
So – how do I pass CproperyPage “this” pointer down the line ? Or is this approach all wrong?
Any constructive help would be greatly appreciated.
Cheers Vaclav
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You are not sending the message anywhere. You need to send it to a specific window, and the pointer should be sent as a parameter; something like:
SendMessage(myHwnd, WM_SERIAL_OUTPUT, 0, (LPARAM)pointer);
where myHwnd is the window handle of your CPropertyPage. Then in your message handler you can recast the pointer and use it to access the object.
Veni, vidi, abiit domum
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Richard ,
I must have muddied the water by using variable name "pointer".
I understand that the first parameter of the message is the handle to the message destination window, so I wanted to use "this" pointer of CProperyPage as such.
For now I am not concerned with the actual message parameters( WPARAM / LPARAM) until I get better understanding of the basic.
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this is a pointer to the class object, not the window handle.
Veni, vidi, abiit domum
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OK. but I should be able to pass it and access the class.
It sure looks as "this" cannot be passed as void*.
But passing "this->m_Hwnd" is OK.
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No, you misunderstand both this and HWND.
this is the implied pointer of the current object. The HWND type is a handle to a Window object, but not to a class object, the two are totally different types. When sending messages between objects the general mathod is to use code of the form:
SendMessage(HWND windowHandle, MSG message, WPARAM wParam, LPARAM lParam);
In your program you wanted to send the pointer to your CpropertyPage object via a WM_SERIAL_OUTPUT message, which could then be used in the receiving window. So your sending code would be something like:
SendMessage(object->m_hWnd, WM_SERIAL_OUTPUT, 0, (LPARAM)this);
And your receiving code would be something like:
BEGIN_MESSAGE_MAP(CMyWnd, CWnd)
ON_MESSAGE(WM_SERIAL_OUTPUT, OnMyMessage)
END_MESSAGE_MAP()
...
LRESULT CMyWnd::OnMyMessage(WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(wParam);
CpropertyPage* prop = (CpropertyPage*)lParam;
return pC_SerialMFC->pC_SerialEx->Open(strPort, 0, 0, true, prop); }
Veni, vidi, abiit domum
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So if I can send this->m_Hwnd why I cannot sent object "this" and retrieve its ( window) HWND in the called process?
But that is strictly academic now, I got it working using exactly what you have described.
Thanks for you help.
Vaclav
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Vaclav_Sal wrote: So if I can send this->m_Hwnd why I cannot sent object "this" and retrieve its ( window) HWND in the called process?
You can, and I have twice shown you how to do it. I suggest you get hold of a book, or look for internet sites, on Windows programming, and read up on Windows message passing and handling.
Veni, vidi, abiit domum
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Well, from your post I couldn't find out what do you do on which thread. Please send more accurate info. Maybe it would be more useful to describe what you want to achieve: a scenario where the user uses this functionality from beginning to the end.
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Solved by passing this->m_hWnd
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you can use SendMessage or PostMessage to send this pointer in same application only...
SendMessage(SENDER_HWND,WM_APP+1,0,(LPARAM)this);
at Receiving side Message callback
CPropertyPage *page = (CPropertyPage *)lparam;
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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Alok,
Ok, either I said it wrong in my OP or I just do not get it.
The doc clearly state the first parameter of Send/Post message is:
hWnd
[in] Handle to the window whose window procedure will receive the message.
You set the first parameter to SENDER_HWND but according to the doc it needs to be the receiver of the message and it works.
As of now I am not using the message WPARAM/LPARAM, just making sure I can get the message to the UI class.
I just need some clarification on this , please.
Thanks for you time.
Vaclav
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I have a ClistView class, I am adding too many columns, 300+. At some point, the last few columns cannot be resized.
Is there a restriction on the number of columns or something to do with pixel sizes allowed?
Any help will be great.
Thanks,
Saleem
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300+ columns? Who is ever going to be able to make head or tail of such a control?
Veni, vidi, abiit domum
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