Re: operations in the cout<< - C / C++ / MFC Discussion Boards

Re: I've got it :-)

prasad_som4-Sep-06 1:39

prasad_som

4-Sep-06 1:39

welcome.

yummi wrote:
Hi Pasrad

I hope,you want to say 'Prasad', Smile | :)

Prasad
Notifier using ATL

CFormView help needed

mkoliv3-Sep-06 6:39

mkoliv

3-Sep-06 6:39

Thanks

modified 28-Sep-16 7:30am.

Re: CFormView help needed

Gary R. Wheeler3-Sep-06 8:14

Gary R. Wheeler

3-Sep-06 8:14

You probably need to call ShowWindow for your controls after you create them.

Software Zen: delete this;

Fold With Us![^]

PlaySound with NULL

YaronNir3-Sep-06 5:30

YaronNir

3-Sep-06 5:30

Hi all,

i play a sound using:

PlaySound(MAKEINTRESOURCE(IDR_WAVE),AfxGetInstanceHandle(),SND_PURGE | SND_RESOURCE | SND_ASYNC);

i stop this sound using:

PlaySound(NULL,AfxGetInstanceHandle(),SND_PURGE | SND_RESOURCE | SND_ASYNC);

But when i call the above line again (PlaySound with NULL), the sound is being played again

is there a way to avoid this problem?

thanks

Yaron

Interface basics click here :
http://www.codeproject.com/com/COMBasics.asp

don't forget to vote Smile | :)

links appearance in the CRichEditCtrl

YaronNir3-Sep-06 5:23

YaronNir

3-Sep-06 5:23

Hi all,

all the links that appear in CRichEdit Ctrl are based on the window scheme i am using.
is there a way to tell the rich edit that all my link will apear in a blue color regardless the window scheme i am using?

thanks in advanced

Yaron

Interface basics click here :
http://www.codeproject.com/com/COMBasics.asp

don't forget to vote Smile | :)

operations in the cout<<

Ahmed Ismail Mohamed3-Sep-06 4:48

Ahmed Ismail Mohamed

3-Sep-06 4:48

int x = 4;
cout<< x+3;

i want to know what is the type of variable holds the expression x+3 in the cout statement.

******************
******************
** Ahmed Ismail **
******************
******************

Re: operations in the cout<<

toxcct3-Sep-06 5:22

toxcct

3-Sep-06 5:22

as both operands of the operator + are integers, the resulting variable is also an integer...

TOXCCT >>> GEII power

[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]

Re: operations in the cout<<

ahmed mega3-Sep-06 9:42

ahmed mega

3-Sep-06 9:42

I think that it's atemporary variable which made in the run time
from the type int to hold the output then it will be destroyed.

Re: operations in the cout<<

MIAN KAMRAN6-Sep-06 1:58

MIAN KAMRAN

6-Sep-06 1:58

it should be int but it is Compiler to decide wrt its Type Expressions

Audio playback in a Win32 Service

dubbaluga3-Sep-06 4:42

dubbaluga

3-Sep-06 4:42

Hello,

I' tried to develop a small application that's able to play MP3s in a windows service. My intention is to build a small media-player. The core of it shall run as a service and the communication between service and frontend is then some kind of IPC (not so important at the moment).

My question is, why applications like Winamp don't want to work as a background service. It only works, if I allow these applications to interact with my desktop. It even does not work, with fmod, that does not rely on a GUI:

===================================================
if (!FSOUND_Init(44100, 64, 0))
{
debug_stream = fopen("c:\\temp\\wmus.log", "w");
fprintf(debug_stream, "%s\n", FMOD_ErrorString(FSOUND_GetError()));
fclose(debug_stream);
exit(EXIT_FAILURE);
}
===================================================

This snippet always fails with "Error setting cooperative level for hardware." when started as a service (it works, when it's executed by a logged-in user) and I think, that this messages comes from DirectSound, since FMOD (http://www.fmod.org) relies on it.

Best regards and thanks for reading,
Rainer

Re: Audio playback in a Win32 Service

Gary R. Wheeler4-Sep-06 3:49

Gary R. Wheeler

4-Sep-06 3:49

I would guess the basic problem you're having is that, since sound is owned by the active desktop, you can't play sound from a service without letting that service interact with the desktop. The whole point of a service is to do work in the background without interacting with the user.

If the effect you are looking for is to have the player running 'in the background' without a main window, you can do that by making the main window a hidden one. You can then set a notification icon to interact with the application when you need to.

Software Zen: delete this;

Fold With Us![^]

Adding two large numbers

Waldermort3-Sep-06 3:14

Waldermort

3-Sep-06 3:14

This is the same with any data type, when 1 large number is added to another and the result is larger than the data type can hold, it wraps around. i.e.

ULONG size1 = 0xFFFFFF00;<br />
ULONG size2 = 0xFFFFFF00;<br />
size1 += size2; // == 0xFFFFFE00

The output is less than the input. I want to check for this problem and if it's there I would prefer the output to be the max value the data type can hold. What is the best way to approach this?

Re: Adding two large numbers

Ahmed Ismail Mohamed3-Sep-06 3:29

Ahmed Ismail Mohamed

3-Sep-06 3:29

waldermort wrote:
ULONG size1 = 0xFFFFFF00;
ULONG size2 = 0xFFFFFF00;

if you divede both size1 and size by a big number that make you sure that you can add and you still in the range of long.
size1 = size1/n;
size2 = size2/n;

waldermort wrote:
size1 += size2; // == 0xFFFFFE00

adding in this line will not make a problem

then finally, when you want to output the final value , make the value the program do it time the number you devide by it:
ex: textbox1.text = Tostring(size2 * n) // n is the number you devided by it.

I hope it work properly with you.
regards; Smile | :)

** Ahmed Ismail **

Re: Adding two large numbers

Waldermort3-Sep-06 3:42

Waldermort

3-Sep-06 3:42

That doesn't work, it produces exactly the same result as simply adding them:

ULONG max1 = 0xFFFFFF00;<br />
ULONG max2 = 0xFFFFFF00;<br />
max1 = max1/4;<br />
max2 = max2/4;<br />
max2 += max1;<br />
max2 *= 4; // == 0xFFFFFE00

The only way I have found is to cast them to a larger data type and check the value using an if else block

if ( ((UINT64)max1 + (UINT64)max2) > 0xFFFFFFFF )<br />
    max2 = 0xFFFFFFFF;<br />
else<br />
    max2 += max1;

But I'm sure there must be a more accurate way of doing it.

Re: Adding two large numbers

Waldermort3-Sep-06 8:26

Waldermort

3-Sep-06 8:26

Ahmed Ismail Mohamed wrote:
i think that you should make max2 *4 only when you output the resualt.

What you are saying makes no sense. Why divide and add when it is taking the result I want further away.

Re: Adding two large numbers

Nader Elshehabi3-Sep-06 4:40

Nader Elshehabi

3-Sep-06 4:40

Hello

Well, if you have some assembly background you'd remember that there is a bit in the status register called overflow bit to check for this error. Anyway, I know how to check for overflow in Assembly and C#, but sorry, my C++ is too rusty to remember how to do it in C++ Big Grin | :-D

.

You are right, there is a better way to detect overflow, yet I will provide you with a simpler way of detecting it. Usualy the overflow result is smaller than any of the two operands. So, try this:

ULONG size1 = 0xFFFFFF00;
ULONG size2 = 0xFFFFFF00;
size1 += size2; // == 0xFFFFFE00

if( size1 < size2)
    size1 = 0xFFFFFFFF;

Remember, maximum value of each type is totally OS dependant. Keep that in mind. Smile | :)

If someone got a better approach, please post. I'll try to remember how to check overflow in C++. If I got anything, I'll keep you posted.

Regards

Re: Adding two large numbers

Waldermort3-Sep-06 7:39

Waldermort

3-Sep-06 7:39

That probably is a better way of doing it. Thinking about it, the output would always be smaller. If you remember the better way, please post it. I would love to know.

Re: Adding two large numbers

toxcct3-Sep-06 5:24

toxcct

3-Sep-06 5:24

use the header <LIMITS.h>

with this, you can know the types max and min values, and some other informations for floating points types.

TOXCCT >>> GEII power

[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]

Re: Adding two large numbers

Rick York3-Sep-06 16:06

Rick York

3-Sep-06 16:06

You could do something like this :

_int64 sum = (_int64)size1 + (_int64)size2;
if( sum > ULONG_MAX )
TRACE( "an overflow occurred\n" );
else
size1 = (ULONG)sum;

Re: Adding two large numbers

Stephen Hewitt3-Sep-06 16:16

Stephen Hewitt

3-Sep-06 16:16

Try this:

ULONG size1 = 0xFFFFFF00;
ULONG size2 = 0xFFFFFF00;
ULONG sizeR = size1 + size2; // == 0xFFFFFE00
if (sizeR < max(size1, size2))
{
    // Overflow.
}

Steve

Re: Adding two large numbers

MayankT3-Sep-06 17:08

MayankT

3-Sep-06 17:08

try this:

<br />
if (MAXVAL - size1 < size2)<br />
{<br />
//overflow<br />
}<br />
else<br />
{<br />
size1 += size2;<br />
}<br />

MAXVAL can be obtained from limits.h as toxcct said.

----------------------
Mayank Thakore
Learning C++ - since 1998

They didn't print my card right; so I resigned.

CString to wchar_t*!!!!!!

mostafa_pasha3-Sep-06 3:13

mostafa_pasha

3-Sep-06 3:13

Hi,
how can i convert CString to wchar_t*? for example
CString m_strFilename;
how can i convert m_strFilename to wchar_t*?

i use L"" for string such that L"c:\filename.cpp", but is
there any function or macro do this?

Best Regards.
MJM

Re: CString to wchar_t*!!!!!!

Waldermort3-Sep-06 3:25

Waldermort

3-Sep-06 3:25

MultiByteToWideChar() is the function you want, but why not just use CStringW?

Re: CString to wchar_t*!!!!!!

mostafa_pasha3-Sep-06 3:33

mostafa_pasha

3-Sep-06 3:33

thanks , I use CStringW !

Re: CString to wchar_t*!!!!!!

messages3-Sep-06 7:50

messages

3-Sep-06 7:50

See

<br />
USES_CONVERSION;<br />
CString str;<br />
str="Test";<br />
<br />
wchar_t* m_wchar = T2W(str.GetBuffer());<br />
str.ReleaseBuffer();<br />
<br />

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.