C / C++ / MFC Discussion Boards

Re: operator overloading

Kiran Pinjala9-May-07 3:38

Kiran Pinjala

9-May-07 3:38

Thank you so much for your reply.

Hans Dietrich wrote:
the two arguments are no longer symmetric - automatic type conversion applies to the second arg only.

I request you to explain what exactly these lines mean? If possible with code.

Thank you.

KIRAN PINJARLA

Re: operator overloading

Hans Dietrich9-May-07 4:04

Hans Dietrich

9-May-07 4:04

Consider a class for Complex numbers, which has an addition operator defined as a member:

class Complex
{
public:
   Complex(double re, double im = 0);
   Complex operator+(const Complex& rhs);
private:
   double re, im;
};

We would like to be able to write code like this:

Complex c1(1,1);
Complex c2 = c1 + 4.5;
Complex c3 = 10 + c1;

The first statement simply constructs the complex number c1 = 1 + 1i. The complex number c2 is obtained by adding 4.5 to c1. Writing the assignment in functional form yields:

c2.operator= ( c1.operator+ ( 4.5 ) );

The addition operator takes a Complex argument. So how does this work when a real number, 4.5, is passed as the argument to operator+? It turns out that the compiler uses the constructor to implicitly convert 4.5 into a Complex by creating a temporary variable in order to perform the addition:

Complex c1 (1,1);
{
   Complex t1 (4.5);
   Complex c2 = c1 + t1;
}

The braces are used to show the scope of the temporary t1 which only exists for the duration of the addition. In functional form this can be written:

c2.operator= ( c1.operator+ ( t1 ) );

Next consider the assignment of c3. In functional form, the statement is written:

c3.operator= ((10.0).operator+ ( c1 ));

In order for this to work, 10.0 must be converted to a Complex. However, the compiler will not implicitly convert the left operand to call a member function on it.

If the addition operator is implemented as a non-member:

Complex operator+ (const Complex& a,
                   const Complex& b);

the compiler will implicitly convert both arguments as needed so that the assignment of c3 will compile. The operator may or may not be a friend depending on how it is implemented.

Implicit conversions are also used for conversion of initializers, function arguments, function return values, expression operands, expressions controlling iteration and selection statements, and explicit type conversions.

Implicit conversions (for left operands) will be performed implicitly by the compiler when the operator is a non-member. If type conversions are undesirable, the operator should be implemented as a member function. Most binary operators, such as addition, should be implemented as non-members since implicit type conversions are desired.

For more details, please consult C++ reference book.

Best wishes,
Hans

Re: operator overloading

Kiran Pinjala9-May-07 4:06

Kiran Pinjala

9-May-07 4:06

I am very very thankful to you.

Wish you all the best.

KIRAN PINJARLA

Dissasembler source code

zon_cpp9-May-07 0:43

zon_cpp

9-May-07 0:43

Hi!
I need a Dissasembler source code, example or article

please help me

Zo.Naderi-Iran

Re: Dissasembler source code

Hans Dietrich9-May-07 0:47

Hans Dietrich

9-May-07 0:47

Here you go.

Best wishes,
Hans

Re: Dissasembler source code

zon_cpp9-May-07 22:35

zon_cpp

9-May-07 22:35

Thank you!
has this source code an article to explain it?

Zo.Naderi-Iran

Help! Plot 3D real time.

Aint9-May-07 0:17

Aint

9-May-07 0:17

Hi.

Anyone have any idea of how or what to use to plot a 3D curve in real-time?
I want the 3D curve to be drawn on the canvas in real time so that we are able to see the curve being drawn at which ever direction.
I have tried to plot the 3D curve using openGL and gnuplot but that is not in real-time.
Thanks!

Re: Help! Plot 3D real time.

Hans Dietrich9-May-07 0:44

Hans Dietrich

9-May-07 0:44

Here is a sample of 3D function plotting.

Best wishes,
Hans

How to change size of DialogBox at run time?

Atul238-May-07 23:47

Atul23

8-May-07 23:47

Hi All
I am using VC++ 6.0 for my project in which i want to change size of DialogBox at runtime.So if anybody have solution to this then plz forward me.

Thanks and Regards
Atul OMG | :OMG:

atul

Re: How to change size of DialogBox at run time?

_AnsHUMAN_ 8-May-07 23:56

_AnsHUMAN_

8-May-07 23:56

From your code - use MoveWindow() or SetWindowPos(). or Do you want to allow the user to drag the dialog from it's corners and resize it?

Somethings seem HARD to do, until we know how to do them.
Wink | ;-)

_AnShUmAn_

Re: How to change size of DialogBox at run time?

Atul239-May-07 2:01

Atul23

9-May-07 2:01

Hi
i use this function in onPaint() funtion in

switch()

{

CDialog* dlg = (CDialog*)GetDlgItem(IDD_DIALOG_NSMESSAGE);

HWND hwnd = dlg->GetSafeHwnd();

SetWindowPos(hwnd,50,50,50,50,SWP_SHOWWINDOW) ;

}

but it does'nt work. Is it a right way or i have to do it by some othere way.

Regards
Cry | :((

Atul

Re: How to change size of DialogBox at run time?

prasad_som9-May-07 2:15

prasad_som

9-May-07 2:15

M. Atul wrote:
. Is it a right way

It is not.
You must understand cases, whenever OnPaint is called. That is not place to change size of window.

Prasad
MS MVP - VC++

Re: How to change size of DialogBox at run time?

Nibu babu thomas9-May-07 0:48

Nibu babu thomas

9-May-07 0:48

M. Atul wrote:
I am using VC++ 6.0 for my project in which i want to change size of DialogBox at runtime.So if anybody have solution to this then plz forward me.

If you just want to change the size call...

CSize csSize( nNewWidth, nNewHeight );
SetWindowPos( 0, 0, 0, csSize.cx, csSize.cy, <code>SWP_NOMOVE</code> | SWP_NOZORDER | SWP_FRAMECHANGED );

Nibu thomas
A Developer

Programming tips[^] My site[^]

Re: How to change size of DialogBox at run time?

ThatsAlok16-May-07 20:36

ThatsAlok

16-May-07 20:36

M. Atul wrote:
Hi
All
I am using VC++ 6.0 for my project in which i want to change size of DialogBox at runtime.So if anybody have solution to this then plz forward me.

where you want to change the size of your dialog box!

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You

get the table name in a .mdb file

hero19958-May-07 23:40

hero1995

8-May-07 23:40

i don't know why the some strange extra table name appear in thelist control:

CListCtrl m_table;
CDaoDatabase db;
db.Open("D:\\ktt.mdb");
short n_table=db.GetTableDefCount( );

CDaoTableDefInfo TableInfo;
for( int i=0; i

Print a CString

Epi8-May-07 23:16

Epi

8-May-07 23:16

Hello,

I have a CString in a CDialog and I want to print it in a Network printer.

I have been taking a look of the diffrent methods to do it but in all of them I have find problems,

For example:

1.-

filebuf fb( "prn:" ); // Filebuf object attached to "prn:"<br />
filebuf fb( "prn:" ); // Filebuf object attached to "prn:"<br />
cout = &fb; // fb associated with cout<br />
cout << "testing"; // Text goes to PRN: not stdout

Can only print to local printer.

2.- CView::OnPrint

I can't use it because I am using CDialog not Cview, CFormView.....

Fixing:

Does any way to print a CString using CPrintDialog?

Thanks in advance,

Best regards

Re: Print a CString

Hans Dietrich9-May-07 0:39

Hans Dietrich

9-May-07 0:39

QPrint may be what you are looking for.

Best wishes,
Hans

Re: Print a CString

Hugo González Castro9-May-07 4:22

Hugo González Castro

9-May-07 4:22

An easy way is to use GetPrinterDC on a CPrintDialog, use StartDoc to begin a new print job, use TextOut to print your CString (you will have to split it...). Use EndPage to end each page you create, and EndDoc to start printing. You have an example at:

http://ourworld.compuserve.com/homepages/tamareg/TechHelp/CPPMiscellaneous.html#Print%20list[^]

Re: Print a CString

Epi9-May-07 22:11

Epi

9-May-07 22:11

Thank you this is what I was looking for,

It is really easy to use.

Regards

VC.net to VC6.0

vibindia8-May-07 22:42

vibindia

8-May-07 22:42

Hi
When an project is created in VC6.0. It can be opened in VC.Net.
But if i create an project in VC.Net, can I open it in VC6.0. WTF | :WTF:

Could i know in which file the version is serialized.

VIBIN

"Fool's run away,where angle's fear to tread"

Re: VC.net to VC6.0

Atul238-May-07 23:50

Atul23

8-May-07 23:50

Hi
U can not open project in VC++ 6.0 which is develop in VC.Net. Because it is advance version so all vc.net features are not in VC++ 6.0.

atul

Re: VC.net to VC6.0

David Crow9-May-07 2:44

David Crow

9-May-07 2:44

vibindia wrote:
But if i create an project in VC.Net, can I open it in VC6.0.

No, but tools do exist to convert from VS2005 back to VS6.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: VC.net to VC6.0

ThatsAlok16-May-07 20:35

ThatsAlok

16-May-07 20:35

vibindia wrote:
But if i create an project in VC.Net, can I open it in VC6.0.

NO, but you can achieve that manually by adding blank solution and project and copying files and setting into them

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You

Urgent Converting stuff

imanos8-May-07 22:15

imanos

8-May-07 22:15

please i was confused a little
i have array of unsigned char where if i print its value by
printf("%2X",stemp);

the value is hexadecimal and it is the desired answer
now i want to write this value into file with its hexa format
how is that possible
please urgently help me

emma

Re: Urgent Converting stuff

_AnsHUMAN_ 8-May-07 22:16

_AnsHUMAN_

8-May-07 22:16

You can use sprintf to change the hexadecimal value into a string format and then write it to a file just like any other string. There could be some other way too, but this is what struck me at this moment.

Somethings seem HARD to do, until we know how to do them.
Wink | ;-)

_AnShUmAn_

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