Re: Count Character in string (even faster) - C / C++ / MFC Discussion Boards

Cedric Moonen20-Nov-07 20:19

20-Nov-07 20:19

Why are you using a BYTE array to store characters ? Do you need to store characters or unsigned characters ?

Can you post the code of your loop, because it shouldn't take too much time to check each character of your string (except if it is exceptionally long).

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Count Character in string

manish.patel20-Nov-07 20:45

manish.patel

20-Nov-07 20:45

I am storing bytes in buffer. And its too long. Thats why i need for in built function.

Any idea?

i had done like this:

int countByte(BYTE *src, BYTE b)<br />
{<br />
	int count = 0;<br />
	for(int i = 0; i < strlen((char *)src); i++)<br />
		if(src[i] == b)<br />
			count++;<br />
	return count;<br />
}

Any Suggestion..

Manish Patel.
B.E. - Information Technology.

Re: Count Character in string

Cedric Moonen20-Nov-07 20:55

Cedric Moonen

20-Nov-07 20:55

Is your buffer NULL-terminated ? If no, then there is a big problem because strlen calculates the lenght of the string by counting the number of characters until it finds a 0.

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Count Character in string

manish.patel20-Nov-07 21:03

manish.patel

20-Nov-07 21:03

Ya, My string is NULL terminated.

My function working properly but it takes to much time for string length greater than 10000.

Please provide me any idea to decrease this time.

Manish Patel.
B.E. - Information Technology.

Re: Count Character in string

KarstenK20-Nov-07 21:04

KarstenK

20-Nov-07 21:04

//this one should run faster
int countByte(BYTE *src, BYTE b)
{
int count = 0;
int i = 0;

while( src[i] )
{
if(src[i] == b)
count++;

i++;
}
return count;
}

Greetings from Germany

Re: Count Character in string

manish.patel20-Nov-07 21:13

manish.patel

20-Nov-07 21:13

Wow its working fine.

Thanks a lot.

Manish Patel.
B.E. - Information Technology.

Re: Count Character in string

Cedric Moonen20-Nov-07 21:44

Cedric Moonen

20-Nov-07 21:44

It was taking so much time because at each iteration of your for loop, you call strlen. And strlen is basically just a loop that counts the number of characters until a 0 is encountered. So, redoing that at each iteration is quite costly.

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Count Character in string (even faster)

bolivar12321-Nov-07 3:06

bolivar123

21-Nov-07 3:06

<br />
typedef unsigned char BYTE;<br />
<br />
int countByte(BYTE *src, BYTE b)<br />
{<br />
   int count = 0;<br />
   BYTE *s;<br />
   for (s=src;*s; s++)<br />
     if (*s == b)<br />
       count++;<br />
   return count;<br />
} <br />
<br />
int _tmain(int argc, _TCHAR* argv[])<br />
{<br />
	char s[20] = "111222333";<br />
	//Count the # of 1's in string s<br />
	printf("%d",countByte((BYTE*)s,'1'));<br />
	return 0;<br />
}<br />

This version eliminates the strlen call and it eliminates the use of the square brackets []. Each time you use the square bracket array index, an offset into your array has to be calculated.

CWnd

kk.tvm20-Nov-07 19:07

kk.tvm

20-Nov-07 19:07

Hi Friends

I anybody have an idea to create a window, that is appeared in top of other windows. ie timeline slider in Windows Movie Maker

thanx in advance

-RisKhan-

Re: CWnd

Hamid_RT20-Nov-07 19:11

Hamid_RT

20-Nov-07 19:11

You can use of SetWindowPos for set it to top.

Re: CWnd

kk.tvm20-Nov-07 21:11

kk.tvm

20-Nov-07 21:11

thanks hamid. One more question, how to create a shapeless window. Do u have idea

thanks

-RisKhan-

Re: CWnd

Hamid_RT20-Nov-07 21:18

Hamid_RT

20-Nov-07 21:18

Do you want to make like this window Simple way to create non-rectangular shaped dialogs[^].

How to SetWindowPos correctly? Actually confused with GetClientRect,GetWindowRect,ScreenToClient and ClientToScreen etc.

fantasy121520-Nov-07 18:36

fantasy1215

20-Nov-07 18:36

when create a dialog based MFC project defaultly, we have the OK, cancel buttons in the topright corner, I want to create a CListBox dynamicly and place it in the position relative to the IDOK button( the top cordination of CListBox is the same as IDOK), so I write my code like below:

first, construct a CListBox in the .h file
CListBox m_ctlBox;

then, within the OnInitDialog

BOOL CMyDialog::OnInitDialog()
{
  CDialog::OnInitDialog();
  m_ctlBox.Create(STYLE, CRect(0, 0, 0, 0), rightcode);
  m_ctlBox.ShowWindow(SW_HIDE);

  //below code to set the position for the CListBox
  CRect rcOK;
  GetDlgItem(IDOK)->GetWindowRect(&rcOK);
  int nBoxWidth = 30;
  int nBoxHeight = 40;
  int nxMargin = 10;
  int nBoxTop = rcOK.top;
  int nBoxLeft = rcOK.left - nxMargin - nBoxWidth;
  m_ctlBox.SetWindowPos(&CWnd::wndTop, nBoxLeft, nBoxTop, nBoxWidth, nBoxHeight, SWP_SHOWWINDOW);
  m_ctlBox.ShowWindow(SW_SHOW);
  return TRUE;
}

but the m_ctlBox's top is not as IDOK's. Really confused with how to use GetClientRect 、GetWindowRect、ScreenToClient and ClientToScreen correctly to set window position correctly.
So I can't write my code to deal with WM_SIZE correctly.

Re: How to SetWindowPos correctly? Actually confused with GetClientRect,GetWindowRect,ScreenToClient and ClientToScreen etc.

Mark Salsbery20-Nov-07 19:01

Mark Salsbery

20-Nov-07 19:01

GetWindowRect() gets coords relative to the screen.
SetWindowPos() is expecting coords relative to the parents client area.

BOOL CMyDialog::OnInitDialog()
{
  CDialog::OnInitDialog();
  m_ctlBox.Create(STYLE, CRect(0, 0, 0, 0), <font color="Red">this</font>);
  m_ctlBox.ShowWindow(SW_HIDE); <font color="Green">//<-- you could create the window without the WS_VISIBLE style to avoid potential flash doing this</font>

  //below code to set the position for the CListBox
  CRect rcOK;
  GetDlgItem(IDOK)->GetWindowRect(&rcOK);
  int nBoxWidth = 30;
  int nBoxHeight = 40;
  int nxMargin = 10;
<font color="Red">  CPoint BoxUpperLeft;
  BoxUpperLeft.y = rcOK.top;
  BoxUpperLeft.x = rcOK.left - nxMargin - nBoxWidth;
  ScreenToClient(&BoxUpperLeft);  <font color="Green">//<-- converts screen coords to coords relative to this window</font>
</font>  m_ctlBox.SetWindowPos(&CWnd::wndTop, <font color="Red">BoxUpperLeft.x</font>, <font color="Red">BoxUpperLeft.y</font>, nBoxWidth, nBoxHeight, SWP_SHOWWINDOW);
  m_ctlBox.ShowWindow(SW_SHOW);
  return TRUE;
}

Mark

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

Re: How to SetWindowPos correctly? Actually confused with GetClientRect,GetWindowRect,ScreenToClient and ClientToScreen etc. [modified]

fantasy121520-Nov-07 20:34

fantasy1215

20-Nov-07 20:34

Question NO.1

BOOL CMyDialog::OnInitDialog()
{  
  CDialog::OnInitDialog();  
  m_ctlBox.Create(STYLE, CRect(0, 0, 0, 0),this);    
  m_ctlBox.ShowWindow(SW_HIDE); //<-- you could create the window without the WS_VISIBLE style to avoid potential flash doing this  
  //below code to set the position for the CListBox  
  CRect rcOK;  
  GetDlgItem(IDOK)-><big><font color="red">GetWindowRect</font></big>(&rcOK);  
  int nBoxWidth = 30;  
  int nBoxHeight = 40;  
  int nxMargin = 10;  
  CPoint BoxUpperLeft;  
  BoxUpperLeft.y = rcOK.top;  
  BoxUpperLeft.x = rcOK.left - nxMargin - nBoxWidth;   
  
  //you use 
  <big>this->ScreenToClient(&BoxUpperLeft)</big>
  <font color=blue>//why not m_ctlBox.ScreenToClient(&BoxUpperLeft); ?
  </font>
  m_ctlBox.SetWindowPos(&CWnd::wndTop, BoxUpperLeft.x, BoxUpperLeft.y, nBoxWidth, nBoxHeight, SWP_SHOWWINDOW); 
  m_ctlBox.ShowWindow(SW_SHOW);  
  return TRUE;
}

Question NO.2
and how to do it with GetClientRect()?

BOOL CMyDialog::OnInitDialog()
{  
  CDialog::OnInitDialog();  
  m_ctlBox.Create(STYLE, CRect(0, 0, 0, 0),this);    
  m_ctlBox.ShowWindow(SW_HIDE); //<-- you could create the window without the WS_VISIBLE style to avoid potential flash doing this  
  //below code to set the position for the CListBox  
  CRect rcOK;  
  GetDlgItem(IDOK)-><big><font color="red">GetClientRect</font></big>(&rcOK);  
  int nBoxWidth = 30;  
  int nBoxHeight = 40;  
  int nxMargin = 10;  
  CPoint BoxUpperLeft;  
  BoxUpperLeft.y = rcOK.top;  
  BoxUpperLeft.x = rcOK.left - nxMargin - nBoxWidth;   
  
  m_ctlBox.SetWindowPos(&CWnd::wndTop, BoxUpperLeft.x, BoxUpperLeft.y, nBoxWidth, nBoxHeight, SWP_SHOWWINDOW); 
  m_ctlBox.ShowWindow(SW_SHOW);  
  return TRUE;
}

-- modified at 2:40 Wednesday 21st November, 2007

Re: How to SetWindowPos correctly? Actually confused with GetClientRect,GetWindowRect,ScreenToClient and ClientToScreen etc.

Parthi_Appu21-Nov-07 0:25

Parthi_Appu

21-Nov-07 0:25

Before going into your question,

GetWindowRect(..) will return the window rect with respect to screen cooridates.

GetClientRect(..) will return the client area of the window, that is regardless of its position the top left point is 0, 0 and right, bottom point is its width and height respectivly

Now for Question 1:
You got the screen coordinate of OK button, now you have to find its coordinate with respect to the dialog and not with the listbox.

For Question 2:
As i said earlier, if you use GetClientRect(..), simply it will return width and height. By knowing only the width and height you can't find its starting (top,left) coordinate.

Do your Duty and Don't expect the Result

Re: How to SetWindowPos correctly? Actually confused with GetClientRect,GetWindowRect,ScreenToClient and ClientToScreen etc. [Understood clearly]

fantasy121521-Nov-07 13:59

fantasy1215

21-Nov-07 13:59

When I see the explaination of the API ::ScreenToClient(), I understand clearly.
GetDlgItem(IDOK)->GetWindowRect(&rcOK);

First, rcOK's coordinates are relative to the upper left of the display screen.

Then compulate the position of the CListBox to the coordinates relative to display screen.

Next we need convert the screen coordinates of the CListBox to the coordinates in the main Dialog's client coordinates.

<br />
BOOL ScreenToClient(<br />
  HWND hWnd,        // handle to window<br />
  LPPOINT lpPoint   // screen coordinates<br />
);<br />
hWnd <br />
[in] Handle to the window <big><font color="red">whose client area will be used </font></big> for the conversion.

so we should pass the dialog's hWnd.

BOOL CMyDialog::OnInitDialog()
{    
  CDialog::OnInitDialog();    
  m_ctlBox.Create(STYLE, CRect(0, 0, 0, 0),this); 
  m_ctlBox.ShowWindow(SW_HIDE); //<-- you could create the window without the WS_VISIBLE style to avoid potential flash doing this    
  //below code to set the position for the CListBox    
  CRect rcOK;    
  GetDlgItem(IDOK)->GetWindowRect(&rcOK);    
  int nBoxWidth = 30;    
  int nBoxHeight = 40;    
  int nxMargin = 10;    
  CPoint BoxUpperLeft;    
  BoxUpperLeft.y = rcOK.top;    
  BoxUpperLeft.x = rcOK.left - nxMargin - nBoxWidth;       

  ::ScreenToClient(this->m_hWnd, &BoxUpperLeft);
  <font color="red">//This code first compulate the CListBox screen coordinate then convert to the Dialog client coordinate</font>   
  
  
  m_ctlBox.SetWindowPos(&CWnd::wndTop, BoxUpperLeft.x, BoxUpperLeft.y, nBoxWidth, nBoxHeight, SWP_SHOWWINDOW);   
  m_ctlBox.ShowWindow(SW_SHOW);    
  return TRUE;
}

If somewhere is wrong, please correct me! thx.

-- modified at 0:17 Thursday 22nd November, 2007

Re: How to SetWindowPos correctly? Actually confused with GetClientRect,GetWindowRect,ScreenToClient and ClientToScreen etc.

Mark Salsbery21-Nov-07 5:15

Mark Salsbery

21-Nov-07 5:15

There's not an API (or CWnd method) I know of to get the rect of a window relative
to its parent, so your GetClientRect() method isn't going to give you the info you need.

Remember, the window rect is the outer bounding rect of the window. The client rect
is the interior of the window, excluding borders, title bar, menu, and other "decorations".
As Parthi mentioned, the client rect's upper left coord is always 0,0.

Controls are windows, so the same rules apply.

About Windows[^]
MapWindowPoints()[^]

Mark

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

GetWindowText in OnKeyDown not correct

followait20-Nov-07 18:26

followait

20-Nov-07 18:26

<br />
class CMyEdit:public CEdit<br />
<br />
void CMyEdit::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)<br />
{<br />
    CEdit::OnKeyDown(nChar, nRepCnt, nFlags); // though called first<br />
    CString s;<br />
    GetWindowText(s);//But s is the previous WindowText<br />
}<br />

I want to use the WindowText as soon as the text is changed, any way?

Thanks.

Re: GetWindowText in OnKeyDown not correct

Hamid_RT20-Nov-07 18:35

Hamid_RT

20-Nov-07 18:35

Why you dont use of EN_CHANGE?

Re: GetWindowText in OnKeyDown not correct

followait20-Nov-07 18:40

followait

20-Nov-07 18:40

Thanxxxxx

Re: GetWindowText in OnKeyDown not correct

Haroon Sarwar20-Nov-07 18:36

Haroon Sarwar

20-Nov-07 18:36

did you try handling the EN_CHANGE message?

Re: GetWindowText in OnKeyDown not correct

followait20-Nov-07 18:40

followait

20-Nov-07 18:40

Thanxxxxx

Re: GetWindowText in OnKeyDown not correct

fantasy121520-Nov-07 18:42

fantasy1215

20-Nov-07 18:42

in the cpp file write
BEGIN_MESSAGE_MAP(CYourEdit, CEdit)
ON_NOTIFY_REFLECT(EN_CHANGE, OnEnChange)
END_MESSAGE_MAP()
afx_msg void OnEnChange(NMHDR *pNMHDR , LRESULT *pResult);
void CYourEdit::OnEnChange(NMHDR *pNMHDR , LRESULT *pResult)
{
CEdit::GetWindowText(str);
//Then use the str to do your work
}

tchar to constant char mfc-vc++

Paulraj G20-Nov-07 17:46

Paulraj G

20-Nov-07 17:46

hi how to convert tchar to const char

paulraj

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