Merge sort - C / C++ / MFC Discussion Boards

Anonymous13-Nov-03 8:13

13-Nov-03 8:13

In my program I have 2 file:input and output.
When I open the first file I am reading the lines where
I have my specific string, other lines I am skiping.
In my output file I need to write my lines with tab delimeter.
How do I do this?

Re: Output file

David Crow13-Nov-03 9:00

David Crow

13-Nov-03 9:00

What are you using to read with: FILE*, istream, CFile, etc?

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Output file

Anonymous13-Nov-03 9:05

Anonymous

13-Nov-03 9:05

I am using istream.

Re: Output file

David Crow13-Nov-03 9:10

David Crow

13-Nov-03 9:10

Then use ostream::write() to write the data to an output stream (e.g., file).

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

StretchDIBits problem with 16-bit (65536) color

tchu13-Nov-03 7:31

tchu

13-Nov-03 7:31

hello all,

my name is durval and i've the following problem in my project:
when the color-palette from the windows-desktop (properties)
16-bit (65536) is set. on ms-c++ print-preview (mfc) the
::StretchBlt(...)/::StretchDIBits(...)/::::BitBlt(...)
doesn't work properly. the bitmap is dividing in 2 parts, the
right (1/3 from the bitmap) will be put on the left place and
the left is displaced to the right.
at all the other color-settings there's no problem: 8-bit, 24-bit...

do you know this problem?
please, if everybody could help me, it would be very nice.

thanx a lot,
durval.
Frown | :(

the code:

BOOL CDib::Draw(CDC* pDC, CPoint origin, CSize size)
{
if(m_lpBMIH == NULL) return FALSE;
if(m_hPalette != NULL)
::SelectPalette(pDC->GetSafeHdc(), m_hPalette, TRUE);
pDC->SetStretchBltMode(COLORONCOLOR);

// ::BitBlt( pDC->GetSafeHdc(), origin.x, origin.y, m_lpBMIH->biWidth, m_lpBMIH->biHeight, memDC.m_hDC, 0, 0, SRCCOPY );

// ::StretchBlt( pDC->GetSafeHdc(), origin.x, origin.y, size.cx, size.cy, memDC.m_hDC, 0, 0, m_lpBMIH->biWidth, m_lpBMIH->biHeight , SRCCOPY );

::StretchDIBits(pDC->GetSafeHdc(), origin.x, origin.y, size.cx, size.cy,
0, 0, m_lpBMIH->biWidth, m_lpBMIH->biHeight,
m_lpImage, (LPBITMAPINFO) m_lpBMIH, DIB_RGB_COLORS, SRCCOPY);
return TRUE;
}

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

system:

Microsoft (R) Windows NT (TM) Workstation
Version 4.0 (Build 1381: Service Pack 6) x86 Uniprocessor Free

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

graphic:

BIOS-Datum: 11/17/20
BIOS-Version: Video memory: 1 MB Device Revision: 2.0
Hardware Version 0.0
Adapter:
Setting: 1280 x 1024 x 65536 75 Hz
Typ: i81xnt4-kompatible Grafikkarte
Description: Intel815 Video Accelerator
Memory: 4 MB
Chip-Typ: Intel815
DAC-Typ: Internal
Driver:
Company: <n a="">
Datei(en): i81xnt4.sys, i81xdnt4.dll
Version: <n a="">, 4.0.32

81386745

Float Roading.

Mike Doner13-Nov-03 7:08

Mike Doner

13-Nov-03 7:08

Hi Guys,

I'm having a heck of a time doing some rounding here, hoping someone has a quick solution.

Example:

CHAR string[xx] = "1.019", null terminated string holding the current release.
FLOAT instver, intended to hold the float value of string ( I want it to be 1.019 )

When I do:

sscanf ( string, "%5lf", &instver );

My result is always: 1.0189999

I've tried:

instver = atof ( string );

And I still get the same results. I've done some peeking around the helpfile, can't find anything that will let me truncate/round the decimal spots.

Anybody?
Thx.
Mike.

Re: Float Roading.

JWood13-Nov-03 8:42

JWood

13-Nov-03 8:42

You are always going to get this degradation of floating point accuracy. You need to read up on how floats are stored in IEEE 754 specification.

Floats are stored as a binary value that is composed of the mantissa and the exponent just like in regular scientific notation, however they are binary, so you are converting a decimal format into binary - this is going to cause round-off error.

It is still basicly fairly accurate. If it is just a cosmetic thing you can use format statements and they will round to the correct value for you. printf("%.3f", val); will do this.

J.
----------------------------

Merge sort

Azury13-Nov-03 6:53

Azury

13-Nov-03 6:53

I'm trying to find "Exact Analysis of Merge sort"- M.Golin & R.Sedgewich - Fourth SIAM Conference on Discrete Mathmatics for my assignment. Could you show me where to find it or if you got it, please send to my email
azury_thanh@yahoo.com
Thank you so much Cool | :cool:

Study is suffering!! Unsure | :~

Re: Merge sort

Dhakad13-Nov-03 20:16

Dhakad

13-Nov-03 20:16

merge sort can be implemented in various ways but a very good way to do it is to use the Divide and Conquer Algo.

it divides the array into two.. then sorst the two seperately and then finally merge them back to get the final sorted one.
we use recursive divide calls to divide the array till we get the array with 2 or 1 element.

it runs in time O(n ln n)
if u need the code and the detailed analysis how to derive the complexity.. then mail me.
hope this satisfies u

Deepesh Dhakad
Indian Institute of Information Technology,Allahabad
India

show fields from a table on a Listbox Control using MFC VC++

swerajan13-Nov-03 5:32

swerajan

13-Nov-03 5:32

I have created a lsitbox control, and got a database into MFC application. i am trying to display data from a particular field into the listbox.when i did this
CListBox* pListBox = static_cast<clistbox*> (GetDlgItem(IDC_COURSE));
pListBox->AddString(m_pSet->m_Course);
it is only showing the first one. how can i make display all, and let me choose from it.please let me know

Re: show fields from a table on a Listbox Control using MFC VC++

David Crow13-Nov-03 9:04

David Crow

13-Nov-03 9:04

swerajan wrote:
pListBox->AddString(m_pSet->m_Course);
it is only showing the first one. how can i make display all,

How about a loop?

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: show fields from a table on a Listbox Control using MFC VC++

valikac13-Nov-03 9:07

valikac

13-Nov-03 9:07

One solution is InsertItem().

Kuphryn

Re: show fields from a table on a Listbox Control using MFC VC++

David Crow13-Nov-03 9:12

David Crow

13-Nov-03 9:12

Which would be for a list control, would it not?

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

LPCOLESTR

act_x13-Nov-03 5:24

act_x

13-Nov-03 5:24

how to convert LPCOLESTR to CString and viceversa ?

Re: LPCOLESTR

Michael Dunn13-Nov-03 8:08

Michael Dunn

13-Nov-03 8:08

See The Complete Guide to C++ Strings, Part II - String Wrapper Classes[^]

--Mike--
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Pinky, are you pondering what I'm pondering?
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thread exit with code 13

avallet13-Nov-03 4:30

avallet

13-Nov-03 4:30

Hi!
I have a dialog based project.
The first dialog is the login, the second the menu.
When I exit from the login (cancel), my thread exits with code 0.
But when I exit from the menu, I close my menu dialog with cancel, and automaticaly my login dialog with CDialog::OnOK(), and the thread exits with code 13.
I don't know where is my bug...
Thanks

Re: thread exit with code 13

Michael Dunn13-Nov-03 8:09

Michael Dunn

13-Nov-03 8:09

Thread exit codes can be whatever you want. The fact that it's non-zero doesn't necessarily indicate an error, and in fact the return code of the main thread of a GUI app is generally not useful.

--Mike--
Ericahist | CP SearchBar v2.0.2 | Homepage | RightClick-Encrypt | 1ClickPicGrabber
"That probably would've sounded more commanding if I wasn't wearing my yummy sushi pajamas."
-- Buffy

WM_CTRLCOLOR

Alton Williams13-Nov-03 3:51

Alton Williams

13-Nov-03 3:51

Hi,
I've subclassed a an edit control from CEdit.
below is what's in the header file:

class CMyEdit: public CEdit<br />
{<br />
public:<br />
void ChangeColour(const unsigned long &bg, const unsigned long &fg);<br />
	// Generated message map functions<br />
protected:<br />
	//{{AFX_MSG(CEditEx)<br />
	afx_msg HBRUSH OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor);<br />
	//}}AFX_MSG<br />
<br />
	DECLARE_MESSAGE_MAP()<br />
private:<br />
	CBrush m_brush;<br />
	unsigned long TextColour;<br />
	unsigned long BKColour;<br />
	CFont m_TextFont;<br />
};<br />
<br />
}<br />

the methods in my C++ files are:

HBRUSH CMyEdit::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor) <br />
{<br />
	HBRUSH hbr = CEdit::OnCtlColor(pDC, pWnd, nCtlColor);<br />
	<br />
	// TODO: Change any attributes of the DC here<br />
	pDC->SetTextColor(TextColour);<br />
	<br />
	// TODO: Return a different brush if the default is not desired<br />
	return m_brush;<br />
}<br />
<br />

void CMyEdit::ChangeColour(const unsigned long &fg, const unsigned long &bg)<br />
{<br />
	TextColour = fg;<br />
	BKColour = bg;<br />
	m_brush.DeleteObject();<br />
	m_brush.CreateSolidBrush(BKColour);<br />
	Invalidate();<br />

My problem is why the method OnCtlColor is NOT being called?
Any explanations

Thanks, Alton

Re: WM_CTRLCOLOR

Steve S13-Nov-03 4:29

Steve S

13-Nov-03 4:29

Have you set a reflection mapping up (ON_WM_CTLCOLOR_REFLECT) in the class's message map?

Steve S

positioning problem

ns13-Nov-03 3:45

13-Nov-03 3:45

In my Cdialog based class, I have three buttons arranged vertically and centered in the dialog at design time. I dont do anything special to the class when I run it. It shows up with the right side of the dialog larger than the left side, i.e. the buttons are no longer horizontally centered. I can I guess do a runtime positioning with MoveWindow etc but am wondering why this is happening. ANything short of runtime positioning I can do at designtime to fix this?
Thanks,
ns

Re: positioning problem

Ravi Bhavnani13-Nov-03 5:23

Ravi Bhavnani

13-Nov-03 5:23

ns wrote:
It shows up with the right side of the dialog larger than the left side,

That shouldn't happen. Windows won't move/align your controls by itself.

/ravi

Let's put "civil" back in "civilization"
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Re: How can I Enable Drag&Drop of IE URL's in my prog

Mike Dimmick13-Nov-03 3:34

Mike Dimmick

13-Nov-03 3:34

DragAcceptFiles is basically a legacy API - this is how Windows 3.1 File Manager used to indicate a file drop onto an application.

Explorer uses the full OLE drag-and-drop protocol. See Transferring Shell Objects with Drag-and-Drop and the Clipboard[^] for some basic information and pointers on how to register for OLE drag-and-drop.

Strange network speed question

Mathias S.13-Nov-03 3:09

Mathias S.

13-Nov-03 3:09

To start my internal net is 100mbit.

I need to read a lot of data ( couple of Gigs ) over the net very frequently.
So I need a program that copies the data and I want to go as fast as possible.

If I copy the files over FTP I get over 10MB/s in transfer speed and task manager shows network usage at 98-99% witch is really great. But I don’t want to use FTP.
I want to read the file from a network share.
And if I do, I only get like 6.5MB/sec so I made my test program to read/write threaded.
Triple buffers and read/write at the same time and stuff. And now I get like 7-7.5 MB (not much of a performance gain)
Anyway network usage only gets up to about 56-59% if I read from network share. I tried reading with different chunk sizes but did not make any difference.

If I copy the file with windows drag'n'drop I get also low speed but a little better, network usage of 62%

I understand that doing a lot of readfile(...) and stuff will generate more io request then receiving data over FTP. But should it really drop so much.

Anyone have any idea of why I can’t get close to 100% network usage when reading from a network share?

/Mathias

Re: Strange network speed question

valikac13-Nov-03 9:10

valikac

13-Nov-03 9:10

The problem depends on the design and implementation of the actual application.

Kuphryn

threads

snmail13-Nov-03 2:59

snmail

13-Nov-03 2:59

Hi.
The callback function is called when it receives some data. But it receives huge amount of data that requires a lot of time to copy. So I want to put this function to some thread. How to do this? I tried to inherit some class from CWinThread :
class MyThread : public CWinThread
{
.....
void SomeCallBack(...);
}

then MyThread m* = new MyThread; m->CreateThread();
but the thread creates and then completed. Why?
How to solwe my problem(how to create thread class that finished existence when I need)? Please, send example if it is possible.
Thankful in advance.

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