C / C++ / MFC

9-Aug-04 7:39

Thanks for the information and your offer to zip and send me the code.

I will look into the Q article, as well as another possibility.

If I think the zipped code would be useful, I'll send you an email.

Thanks again for the offer.

sizeof(class) question

kfaday9-Aug-04 1:43

Re: sizeof(class) question

9-Aug-04 1:43

Hi, i've got this class

template<class t=""> class pointer
{
private:
T *p;
};

and i get 4 if i do sizeof(pointer).
if i add a static member data, it doesn;t count. why is it that? is it because there's only one copy of that atribute for all the instances of the class?

then, if i add a virtual function (or 2, or 3), i get 8 if i do sizeof(pointer). why is that?

thanks for your help!

gokings9-Aug-04 1:50

Re: sizeof(class) question

9-Aug-04 1:50

Adding a static member does not affect the size because a static member does not exist in an object (instantiation) of the class. The memory for the static member is allocated in ONE place, not for each object.

The reason that the size increases when you add a virtual method, is that the object needs a pointer to the VTable. This is a table of pointers, one for each virtual method. This table is specific to your class. Each object of the class will contain a pointer to this VTable. The size of this pointer is 4 bytes.

kfaday9-Aug-04 13:15

Operator for casting a class to void*

9-Aug-04 13:15

thanks~!

kfaday9-Aug-04 1:40

Re: Operator for casting a class to void*

9-Aug-04 1:40

Hi, i would like to know hot to implement an operator to cast a class to void*.
I thought of overloading operator (), but i don't know how to proceed (as i didn't find anything on the web). Any ideas?
thanks!!

Re: Overloading

4apai9-Aug-04 1:47

4apai

9-Aug-04 1:47

The following example overloads the + operator to add two complex numbers and returns the result.
// operator_overloading.cpp
// compile with: /EHsc
#include <iostream>

using namespace std;
class Complex
{
public:
Complex( double r, double i ) : re(r), im(i) {}
Complex operator+( Complex &other );
void Display( ) { cout << re << ", " << im << endl; }
private:
double re, im;
};

// Operator overloaded using a member function
Complex Complex::operator+( Complex &other )
{
return Complex( re + other.re, im + other.im );
}

int main()
{
Complex a = Complex( 1.2, 3.4 );
Complex b = Complex( 5.6, 7.8 );
Complex c = Complex( 0.0, 0.0 );

c = a + b;
c.Display();
}

David Crow9-Aug-04 2:35

David Crow

9-Aug-04 2:35

Something like:

class MyClass
{
public:
    operator LPVOID() const
    {
        return ???;
    }
};

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: Operator for casting a class to void*

kfaday9-Aug-04 13:14

Re: Operator for casting a class to void*

9-Aug-04 13:14

what do you mean with ???

thanks!

David Crow10-Aug-04 2:44

David Crow

10-Aug-04 2:44

Since you did not tell us anything about your class, I obviously don't know what that method needs to return.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Dynamic Toolbar :sigh:

rerereerer9-Aug-04 1:31

rerereerer

9-Aug-04 1:31

hi ,
I want to change the toolbar at click of a button .I am new to vc++ and i dont know how to solve this task.Any help would be much appreciated . thanks in advance .

regards,
vinod Confused | :confused:

Re: Dynamic Toolbar :sigh:

John R. Shaw9-Aug-04 5:28

John R. Shaw

9-Aug-04 5:28

Here is a partial clip for switching toolbars, from "The MFC Answer Book":

UINT nIDFrom = ::GetWindowLong( pBarFrom->GetSafeHwnd(), GWL_ID );
UINT nIDTo = ::GetWindowLong( pBarTo->GetSafeHwnd(), GWL_ID );

::SetWindowLong( pBarFrom->GetSafeHwnd(), GWL_ID, nIDTo );
::SetWindowLong( pBarTo->GetSafeHwnd(), GWL_ID, nIDFrom );

pFrame->ShowControlBar( pBarFrom, FALSE, bDelay );
pFrame->ShowControlBar( pBarTo, bVisible, bDelay );

This example is used to switch between toolbars that only differ in the size of the buttons. It could also be used to switch between a toolbar that contains image buttons and one that uses test buttons instead.

I hope that helps!

INTP

Terminal Services Client. IMsTscAx

4apai9-Aug-04 1:27

4apai

9-Aug-04 1:27

i use IMsTscAx control to connect to the TS Server.
setting valid server name and so on i finnaly call connect method. he return s_ok. but exploring other property's values i find that startconnected property is false - thats mean that control is not trying to connect. as a sequel connected property is false too.
what do i do wrong?

regards

Obtaining screen dimensions

gokings9-Aug-04 1:16

9-Aug-04 1:16

Can anyone tell me how to obtain the screen dimensions in an MFC app?

Thanks

4apai9-Aug-04 1:30

4apai

9-Aug-04 1:30

it doesnt seems to be mfc. but its simply call api functions:
GetSystemMetrics(SM_CXSCREEN);
GetSystemMetrics(SM_CYSCREEN);

gokings9-Aug-04 1:57

9-Aug-04 1:57

Awesome, thanks!

V.9-Aug-04 1:42

9-Aug-04 1:42

Get SystemMetrics will do the trick, if you'd like to substract the taskbar of other toolbars => use SystemParametersInfo.

"If I don't see you in this world, I'll see you in the next one... and don't be late." ~ Jimi Hendrix

gokings9-Aug-04 1:56