C / C++ / MFC

Re: what do functions like this behave like

1-Nov-05 17:24

http://www.possibility.com/Cpp/const.html[^]

-prakash

ddmcr2-Nov-05 0:08

ddmcr

2-Nov-05 0:08

Consider we have a class CFoo

CFoo
{
protected :
        //...//
     char* m_sText;
        //...//
public : 
        //...//
     char* getText() const; 
        //...//
   
}

char* CFoo::getText() const
{
return m_sText;
}

By writing const keyword we make sure that CFoo::getText function does not modify the object for which it is called.So we can't write inside , for example :

char* CFoo::getText() const
{
m_sText="Hello"; //error
return m_sText;
}

"Success is the ability to go from one failure to another with no loss of enthusiasm." - W.Churchill

Re: what do functions like this behave like

Renjith Ramachandran2-Nov-05 3:15

Renjith Ramachandran

2-Nov-05 3:15

its a constant function, that can't modify variables with in that function, the compiler will raise an error on that situation.

Ninety-eight percent of the thrill comes from knowing that the thing you designed works, and works almost the way you expected it would. If that happens, part of you is in that machine.

Win32 Vs MFC

urssmiling1-Nov-05 17:01

urssmiling

1-Nov-05 17:01

Hi all,

I have been working in VC++. But I got some basic dobts to be cleared. That is the difference between Win32 application and MFC. I got the "Programming Visual C++" book (its more of MFC) . Can any one suggest me for a good book for win32 application learning. As of i know win32 is the base for MFC. Is "Programming windows by charlespetzold" is it for learning win32 application??? Could anyone help me the difference between MFC and win32?? And provide me some good meterial for that.

Thanks in advance.

Prakash Nadar1-Nov-05 17:25

1-Nov-05 17:25

http://www.codeproject.com/cpp/mfc_architecture.asp[^]

-prakash

urssmiling2-Nov-05 0:45

urssmiling

2-Nov-05 0:45

Hi,

I have read that article already. I want to know more about it. My question is that Is the 'programming windows by charlesPetsold' book for win32 application?? Could u sujjest me some good books on it.

aseef2-Nov-05 1:46

aseef

2-Nov-05 1:46

PREVIOUSLY IN THE EARLIER VERSIONS OF VC++...i mean vc++5.0 and so the applications were win16 but still they were called mfc as they use windows programming compileres.
in win32 or win16 all the related code should be written by the programmer.
where as mostly mfc's have built in procedures and functions that are generated by wizard.
examples for win32 are console applications,api...etc
all the win32 applications can also be called as sdk.
(software development kit)
if u really want to rule win32 and mfc my suggestions is to view the generated code in mfc's and try to write that code seperately using win32 applications.
happy coding. Smile | :)

Asif

urssmiling2-Nov-05 2:17

urssmiling

2-Nov-05 2:17

Thank you for ur reply. So for doing win32 application can i refer "programming windows" by charles petzold book.

How to receive SB_THUMBPOSITION

Blake Miller2-Nov-05 3:48

Blake Miller

2-Nov-05 3:48

Yes, as long as you don't get the similar version of the book he wrote that is related to the MFC programming - check the book titles carefully. Get a newer edition of it as well, since that discusses Win32 programming - his earlier editions talked about Win16 programming.

Luke Murray1-Nov-05 16:51

1-Nov-05 16:51

Hey all, I have a dialog that has a richedit control on it. I receive EN_VSCROLL messages through the WM_COMMAND message in the parent window. I can not figuer out how to catch the SB_THUMBPOSITION message.

To catch the EN_VSCROLL messages I had to set the event mask SendMessage(hrichEdit, EM_SETEVENTMASK, 0, LPARAM(SendMessage(hwndDlg, EM_GETEVENTMASK, 0, 0) | ENM_SCROLL ));

Any ideas?

Cheers,

Luke

Prakash Nadar1-Nov-05 17:30

1-Nov-05 17:30

Luke Murray wrote:
SendMessage(hrichEdit, EM_SETEVENTMASK, 0, LPARAM(SendMessage(hwndDlg, EM_GETEVENTMASK, 0, 0) | ENM_SCROLL ));

is hwndDlg intentional instead of hrichEdit?

-prakash

Luke Murray1-Nov-05 17:52

1-Nov-05 17:52

Sorry that is meant to be hrichEdit, like
SendMessage(hrichEdit, EM_SETEVENTMASK, NULL, LPARAM(SendMessage(hrichEdit, EM_GETEVENTMASK, 0, 0) | ENM_SCROLL ));

From what I have read. if you have a winproc for a window you can catch WM_VSCROLL and LOWORD(lParam) will be SB_THUMBPOSITION. the issue I have it when its a scroll message from a child window (like in this case) first you catch WM_COMMAND then EN_VSCROLL through HIWORD(wParam) and lParam in this case is the handle to the richedit control. So i'm not sure how to get the message for SB_THUMBPOSITION from the child window.

I guess I have to have a winproc for the richedit control and handle it through the WM_VSCROLL etc? Then i'm not too sure on how to do that. The dialog is loaded from a resource file as well.

Cheers,

Luke

Prakash Nadar1-Nov-05 18:00

1-Nov-05 18:00

humm, you might want to do subclassing.

-prakash

Luke Murray1-Nov-05 18:07

1-Nov-05 18:07

Yeah, that was something I hoped to avoid. I really would have thought there would be a way.

Calc202-Nov-05 0:39

Calc20

2-Nov-05 0:39

You have to catch WM_HSCROLL or WM_VSCROLL messages and in the WPARAM argument you can find SB_THUMBPOSITION or some other code depending on what the user is doing with the scroll bar.

Luke Murray2-Nov-05 10:59

2-Nov-05 10:59

The problem is WM_VSCROLL etc get sent to the richedit control, not my dialog. the winproc in my dialog I have to catch WM_COMMAND and in that wparam is EN_VSCROLL, and the lparam is the richedit handle, so I lose the SB_THUMBPOSITION and SB_BOTTOM etc.

If i subclassed the richedit and had a winproc for that i could get the WM_VSCROLL messages. but I did not want to sub class the richedit.

Thanks anyway

Luke

Luke Murray2-Nov-05 11:59

2-Nov-05 11:59

Well, I got it. If you add ENM_SCROLLEVENTS to the event mask, you will get the messages through WM_NOTIFY. Then the lParam is a pointer to a MSGFILTER stucture, which gives us the message code of original message, in this case WM_VSCROLL, and LOWORD(msgFilter->wparam) is the SB_*

N ow this is great. Only problem now is the mouse wheel does not fire this event, but it did fire the EN_VSCROLL through WM_COMMAND. annoying.

Thanks all

Luke Murray2-Nov-05 12:04

How to improve my record program's quality?

2-Nov-05 12:04

My bad, the wheel does fire the WM_VSCROLL through WM_NOTIFY. it did ever trigger the SB_ENDSCROLL which I was also testing for.

extraf1-Nov-05 16:30

extraf

1-Nov-05 16:30

I write a record program ,But it's quality is very poor,What effect the
quality except the format

Re: How to improve my record program's quality?

Prakash Nadar1-Nov-05 16:46

1-Nov-05 16:46

bit rate at which the recording was done,

for example 128 bps gives almost a CD-quality recording.

Other possible reason could be your hardware.

-prakash

Debug VS Release

FarPointer1-Nov-05 16:24

FarPointer

1-Nov-05 16:24

Hi,
why is that some errors come in the release mode ,but not in debug mode ,like

Char ch[1];
then i try to copy the wholeno(1,2,....) into it ,it crashes in the release mode but not in the debug mode ,does it assign more space in the debug mode to the ch(in memory) more than told.

Regards
Farpointer

Re: Debug VS Release

Prakash Nadar1-Nov-05 16:45

1-Nov-05 16:45

can you provide us with the copying code?

sometimes programming errors escapes in the debug mode and ideally there is no difference between the functionalit of debug and release apis.

-prakash

Re: Debug VS Release

Prakash Nadar1-Nov-05 17:37