C / C++ / MFC

Can I change defined value or const value?

9-Mar-09 20:22

You can use of CDatabae class:
Using the CDatabase class to read an Access databases[^].

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Re: DATABASE W ITH MFC

hrishiS9-Mar-09 21:43

hrishiS

9-Mar-09 21:43

thanks for your valuable reply

It works fine.But not able to create an object of CDatabase in a generic class.
Actually I want to access the database reading functions from different dialogs. So I thought of having a class in the application, and I can create the object of that class from any dialog class and use the functions(read_database_data).
But I am not able to create the CDatabase object , since it is a generic class. I know I have to inherit something .
Could you please suggest.
Also please suggest if the idea of creating the global class is alright.(All I needed is to call a function from different dialog classes).

thanks

I am a beginner

Re: DATABASE W ITH MFC

David Crow10-Mar-09 3:54

David Crow

10-Mar-09 3:54

himangshuS wrote:
But not able to create an object of CDatabase in a generic class.

This makes no sense. You can do the following from within any class:

CDatabase db1;
CDatabase *db2 = new Database();

himangshuS wrote:
Also please suggest if the idea of creating the global class is alright.(All I needed is to call a function from different dialog classes).

I see nothing wrong with that approach.

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CView problem

prithaa9-Mar-09 20:19

prithaa

9-Mar-09 20:19

Hello,

I have created ac CView object for a CMDIChildWnd but now I am not able to destroy it.It works fine otherwise . But how to destroy an object of type CView .
I am not useing Doc-View Achitecture and have no idea or little about CRuntime Class.

Prithaa

Re: CView problem

Code-o-mat9-Mar-09 22:51

Code-o-mat

9-Mar-09 22:51

Give more details, please, how do you mean "destroy it", how/when you try to do it and what happens?

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Re: CView problem

prithaa9-Mar-09 23:47

prithaa

9-Mar-09 23:47

thanks for your reply

I got my problem

z01e9-Mar-09 20:17

z01e

9-Mar-09 20:17

First i wrote this code to test some algorithm. And it's work but somehow there is a problem when i assemble it with another program. This is some code of my program.

<br />
#define numpic 2 // or const int numpic = 2;<br />
#define numline 20 // or const int numline =20;<br />
int numpictest;<br />
<br />
void swapy(int a[numline][numpic])<br />
{<br />
...<br />
}<br />
<br />
void main()<br />
{<br />
	readnumpic(numpictest); // get value<br />
	numpic = numpictest; // This one get error!! because i can't change defined value or const value<br />
        int size[numpic]; <br />
        ...<br />
}<br />

As you can see that my function and declaration use the value from defined value. But i want this program to be more dynamic (I can change the "numpic" and "numline" variable in main). So is there a way i can change defined value or const value?

Thank you for every help.

Hamid_RT9-Mar-09 20:20

9-Mar-09 20:20

You cant change value of constants.

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Cedric Moonen9-Mar-09 21:42

Cedric Moonen

9-Mar-09 21:42

z01e wrote:
So is there a way i can change defined value or const value?

Why would you do that ? If it is constant, it means it can't be modified. Why do you declare it as constant then ?
And for the #define, it is just a preprocessor directive: before compiling your sources, every occurence of the text "numpic" will be replaced by the text "2". So, it's normal that you can't assign anything to it.

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer10-Mar-09 1:07

10-Mar-09 1:07

As Cedric said, think about what the compiler sees.

#define numpic 2
...
numpic = numpictest;

becomes:

2 = numpictest;

You would not expect that to work.

As for the other option...

Look up the work "constant" in the dictionary.

If you want it to be casually changable, that is the exact opposite of a constant. A Variable.

I'm not sure how to give a more helpful / friendly answer, as it will depend a lot on the rest of your application, and how you're interacting from different programs. Do you want to pass a number as a parameter?

ie:

myalgorithmapp.exe /pi=7.2

?

Iain.

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Can we capture sound using c++?

KarstenK10-Mar-09 2:12

KarstenK

10-Mar-09 2:12

a #define gots compiled fixed as value in the build, so you cant change it. D'Oh! | :doh:

int numpic = 2;

You better wrote that your a newbie Blush | :O

Greetings from Germany

Markandaiya Harsh9-Mar-09 20:17

9-Mar-09 20:17

hi, my question is can we capture sound using c++? if yes how do we do that?? please help me!!

Hamid_RT9-Mar-09 20:19

9-Mar-09 20:19

Yes you can do it with MCI's (MCI_RECORD).
A Simple Voice Recording Application Using MCI[^].

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

ShiXiangYang9-Mar-09 21:25

ShiXiangYang

9-Mar-09 21:25

MCI_OPEN_PARMS mciOpen;
mciSendCommand(NULL,MCI_OPEN,MCI_OPEN_ELEMENT,(DWORD)(LPVOID&mciOpen);
DWORD m_waveID=mciOpen.wDeviceID;
MCI_RECORD_PARMS mciRecord;
mciRecord.dwFrom=0;
mciSendCommand(m_waveID,MCI_RECORD,MCI_FROM,(DWORD)(LPVOID)&mciRecord);

Hamid_RT9-Mar-09 21:29

9-Mar-09 21:29

Thank you but I need to use it or see it! Big Grin | :-D

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Markandaiya Harsh12-Mar-09 1:37

12-Mar-09 1:37

Sir I wasn't able to understand the code u proposed to me can u please give me a simpler code or can u explain me that code (mci)....sir please guide me.
thank you .

Hamid_RT12-Mar-09 20:01

Re: Can we capture sound using c++? - On "ShiXiangYang"'s behalf

12-Mar-09 20:01

That code was easy first you need to set your device (waveaudio) and then you need to open it for use then you need to set MilliSeconds that you want to record and then you send MCI_RECORD to your device and finaly you need to save ypur file with set its name(MCI_SAVE).

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Iain Clarke, Warrior Programmer10-Mar-09 1:09

Iain Clarke, Warrior Programmer

10-Mar-09 1:09

He wrote this reply for you. Please reply to his message, not mine!
http://www.codeproject.com/script/Forums/View.aspx?fid=1647&msg=2957301[^]
- Iain.

-------------------------

MCI_OPEN_PARMS mciOpen;
mciSendCommand(NULL,MCI_OPEN,MCI_OPEN_ELEMENT,(DWORD)(LPVOID&mciOpen);
DWORD m_waveID=mciOpen.wDeviceID;
MCI_RECORD_PARMS mciRecord;
mciRecord.dwFrom=0;
mciSendCommand(m_waveID,MCI_RECORD,MCI_FROM,(DWORD)(LPVOID)&mciRecord);
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Codeproject MVP for C++, I can't believe it's for my lounge posts...

I need a source code in c++.

Markandaiya Harsh9-Mar-09 20:12

9-Mar-09 20:12

I need a source code for a program which takes sound as its input and tell the user which note(for the octate) was played,was the note correct or not. where can I get its scource code. please help me.

_AnsHUMAN_ 9-Mar-09 20:16

_AnsHUMAN_

9-Mar-09 20:16

Some questions.

Markandaiya Harsh wrote:
I need a source code for a program which takes sound as its input

From where does it take the input. Do you read it from some device?

Markandaiya Harsh wrote:
user which note(for the octate) was played,

How does the user play a sound?

Markandaiya Harsh wrote:
where can I get its scource code

This[^] may help

You need to google first, if you have "It's urgent please" mentioned in your question.
Wink | ;-)

_AnShUmAn_

Hamid_RT9-Mar-09 20:17

9-Mar-09 20:17

Do you need an example like a piano?

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Markandaiya Harsh9-Mar-09 20:19

9-Mar-09 20:19

yes i do need an example like piano..

Hamid_RT9-Mar-09 20:28

9-Mar-09 20:28

See CPianoCtrl - A Display Piano Control[^].

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Markandaiya Harsh9-Mar-09 20:42