C / C++ / MFC

9-Aug-08 2:28

Hello everyone,

I am shamed to ask this question because I can not figure out after some experiment. I think for reference variable, once it is binded, the target can not be changed.

But why in my following sample, pi can be binded to a and later binded to b without any issues?

int main()
{
	int a = 10;
	int b = 20;
	int& pi = a;
	pi = b;
	
	return 0;
}

thanks in advance,
George

Mark Salsbery9-Aug-08 5:57

Mark Salsbery

9-Aug-08 5:57

I don't know what you mean by "binded".

All you are doing is assigning a value to a variable...
You are free to assign any value to a non-const variable,
as many times as you want to.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

George_George10-Aug-08 14:53

10-Aug-08 14:53

Thanks Mark!

Cool.

regards,
George

Mark Salsbery11-Aug-08 5:41

Mark Salsbery

11-Aug-08 5:41

Heh don't thank me - my reply made no sense.

Jijo and Nemanja have it right Smile | :)

Cheers,
Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

George_George11-Aug-08 19:54

Re: change the target of a reference [modified]

11-Aug-08 19:54

Good man, thanks Mark! Participation is also appreciated. Smile | :)

regards,
George

Jijo.Raj9-Aug-08 6:25

Jijo.Raj

9-Aug-08 6:25

George_George wrote:
int& pi = a;

In this statement you're initializing your reference variable. Now pi refers to variable a.

George_George wrote:
pi = b;

In this statement you're assigning a value to your reference variable which will updates the value of variable a. Don't get confused - This is not re-initialization, Its just assignment.

George_George wrote:
I think for reference variable, once it is binded, the target can not be changed.

Yes. Thats right. ~~You cannot re-initialize a reference.~~
<modified with respect to Mark's comment>
Once reference is initialized and binded to one variable, you cannot re-initialize it or re-bind it to point another variable. But in your case, the statement pi = b; is just assignment. Thats why its legal. Wink | ;)

Regards,
Jijo.

_____________________________________________________

http://weseetips.com[^] Visual C++ tips and tricks. Updated daily.

modified on Sunday, August 10, 2008 1:33 AM

Mark Salsbery9-Aug-08 11:28

Mark Salsbery

9-Aug-08 11:28

Jijo raj wrote:
Yes. Thats right. You cannot re-initialize a reference.

What do you mean by that?

*edit*  I see - you were illustrating the difference between<br />
initialization and assignment, right?

Thanks,
Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Jijo.Raj9-Aug-08 19:32

Jijo.Raj

9-Aug-08 19:32

Mark Salsbery wrote:

*edit* I see - you were illustrating the difference between
initialization and assignment, right?

Yes Mark.

Regards,
Jijo.

_____________________________________________________

http://weseetips.com[^] Visual C++ tips and tricks. Updated daily.

George_George10-Aug-08 14:54

10-Aug-08 14:54

Cool, thanks Jijo!

regards,
George

Smith#10-Aug-08 2:24

Smith#

10-Aug-08 2:24

Binding?

the use of reference variable is that it can be made to point to anything. Imagine it like a minutes pointer in a wall Clock. It can be rotated any degree to point to I,II,III,IV Smile | :)

. here a,b is just like the I, II. You can turn your reference onto anything. No binding happens, but "referencing".

George_George10-Aug-08 14:56

10-Aug-08 14:56

Thanks Smith,

From here, I got the answer. Any comments? Agree or not? Smile | :)

http://www.codeproject.com/script/Forums/View.aspx?fid=1647&msg=2671657[^]

regards,
George

Nemanja Trifunovic10-Aug-08 12:10

Nemanja Trifunovic

10-Aug-08 12:10

George_George wrote:
But why in my following sample, pi can be binded to a and later binded to b without any issues?

It is not. The line

pi = b;

does not bind pi to b, but assignes a new value to a

Programming Blog

utf8-cpp

George_George10-Aug-08 14:57

Access Vector Objects by ID

10-Aug-08 14:57

You are correct, Nemanja!

regards,
George

Ehsan Baghaki9-Aug-08 1:04

Ehsan Baghaki

9-Aug-08 1:04

Hi, I just want to know if it's possible to access a vector object by it's unique id.
In vector objects don't have id's you can just access them by their locations!

for example:

std::vector<myobject> objs;
objs.at(1).my_property = 'qwerty';

here 1 is the location of the object in that vector and it's not unique..
it can change if you delete or add a object on top of this object.

but i want to give them a unique id and access them by that.
Any suggestions?

Re: Access Vector Objects by ID

super_ttd9-Aug-08 1:07

super_ttd

9-Aug-08 1:07

you must use a std::map instead if you want to identify a record with a unique key.

Help file(.chm) in MFC !

Le@rner9-Aug-08 1:01

Trying to use vista icon in my vc2005 application gives error

9-Aug-08 1:01

Hi all,

i m using *.chm as a help file of application.i m open this through menu of application.

In help file diffrent categories like Contents,Index,Search,Favorite etc.
i want if i click on contents menu than help file open with Contents category,same for others.

so please tell me how can i do this.

Thanks in advance.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

VCProgrammer9-Aug-08 0:01

VCProgrammer

9-Aug-08 0:01

Hi all,

i am trying to use a vista icon in my vc2005 application, by vista i mean that it changes it size according to its view. Now when i import that icon in my application and compile that application it gives error

error RC2176 : old DIB in G:\all__size_ico\Custom Software Box CD.ico; pass it through SDKPAINT

..

How to resolve this error???

Can anybody help me in this...

thanks in advance

Re: Trying to use vista icon in my vc2005 application gives error

Le@rner9-Aug-08 1:08

marshall proxy interface pointer

9-Aug-08 1:08

chk this

http://www.rw-designer.com/compile-vista-icon[^]

and

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=446984&SiteID=1[^]

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

George_George8-Aug-08 23:17

Global interface table release issue

8-Aug-08 23:17

Hello everyone,

Mentioned here,

--------------------
http://www.codeproject.com/KB/COM/CCOMThread2.aspx

However, one down side to this feature is that it does not support the marshaling of proxies. This is a disappointment because table marshaling of proxies is most useful in many situations especially in distributed applications.

To cater to this specific requirement, Windows NT 4.0 Service Pack 3 introduced the Global Interface Table (GIT).
--------------------

Really confused about reading it. Does it mean in current Windows version, GIT has supported the marshalling of pointer to proxies, but in early version of Windows, it is not supported?

thanks in advance,
George

George_George8-Aug-08 23:10

8-Aug-08 23:10

Hello everyone,

When using GIT to perform inter-apartment marshalling, what is the guideline whether need to call Release method of GIT?

Currently, I just call Release in the methods,

- which register interface to be marshalled into GIT;
- which retrieves unmarshalled interface from GIT.

Not sure whether there are more accurate practices when we should call Relase.

thanks in advance,
George

Auto close Dialog box.

Le@rner8-Aug-08 21:47

Re: Auto close Dialog box.

8-Aug-08 21:47

Hi all,

i m using a dialogbox witout close button.i want this dialog box is auto close after some time.

so please tell me how can i do this?

Thanks in advance.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

Naveen8-Aug-08 21:51

Naveen

8-Aug-08 21:51

Add a timer using SetTimer() function and when the timer triggers, call EndDialog().

nave

[OpenedFileFinder]

Re: Auto close Dialog box.

Le@rner8-Aug-08 22:04