Re: how to calculate an array's length? - C / C++ / MFC Discussion Boards

problem in communication between three systems using RS 232

naveen27gupta3-Jul-07 0:38

3-Jul-07 0:38

I have done an application in which i need to interact with 2 other systems using RS 232 cables.
Individually i am able to communicate with either systems but facing problems when executed and trying to interact with 2 systems simultaneously. The main reason for this is the I am using a Pentium 3 processor which is a must for me.Can anyone help me out to overcome this problem in pentium 3 processor.

NAVEEN

Re: problem in communication between three systems using RS 232

CPallini3-Jul-07 1:01

CPallini

3-Jul-07 1:01

naveen27gupta wrote:
The main reason for this is the I am using a Pentium 3 processor

Why the above is the main reason? Confused | :confused:

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Re: problem in communication between three systems using RS 232

CodyDaemon3-Jul-07 4:35

CodyDaemon

3-Jul-07 4:35

Your not trying to just connect the PCs together like this are you?

PC 1 <---\
PC 2 <---|
PC 3 <---/

Just connect all 3 ports together... RxD to RxD to RxD etc.

how to calculate an array's length?

Peter, Chan3-Jul-07 0:08

Peter, Chan

3-Jul-07 0:08

A simple question.
I define an array.How to calculate its length?

int[] arInt = { 1, 2, 3 ,4, 5 };

Thanks in advance.

Re: how to calculate an array's length?

khan++3-Jul-07 0:25

khan++

3-Jul-07 0:25

Peter, Chan wrote:
int[] arInt = { 1, 2, 3 ,4, 5 };

The correct syntax should be:
int arInt[] = {....

int nSize = sizeof(arInt) / sizeof(int);

this is this.

Re: how to calculate an array's length?

Peter, Chan3-Jul-07 0:36

Peter, Chan

3-Jul-07 0:36

Then if it is a array of string.Should I write like this.

char * arLang[] = {"english", "chinese"};
int nSize = sizeof(arLang) / sizeof(char);

Re: how to calculate an array's length?

baerten3-Jul-07 0:48

baerten

3-Jul-07 0:48

Nope

Then you get the number of char's in the array, not the number of strings
You can't count it this way, because each string has a different lenght.

You can determine the length of arLang, then loop on it and count the occurence of \0 (End of a String)
So you get the number of strings in the array, if i tell no mistakes Smile | :)

Good luck

Re: how to calculate an array's length?

khan++3-Jul-07 0:48

khan++

3-Jul-07 0:48

No, it can't be done with multi-dimensional arrays.

You can only do it with single-dimensional arrays like:
char arLang[] = {"english"};
And the length will be 8 bytes.

And whenever you get the operator * anywhere, you just can't be sure of the size.

But you can write:

int nSize1 = strlen(arLang[0]) + 1;<br />
int nSize2 = strlen(arLang[1]) + 1;

etc.

this is this.

Re: how to calculate an array's length?

CPallini3-Jul-07 0:59

CPallini

3-Jul-07 0:59

Peter, Chan wrote:
int nSize = sizeof(arLang) / sizeof(char);

Mistake!

change as follows:

int nSize = sizeof(arLang) / sizeof(char *);

or (better):

int nSize = sizeof(arLang) / sizeof(arLang[0]);

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Re: how to calculate an array's length?

_AnsHUMAN_ 3-Jul-07 0:28

_AnsHUMAN_

3-Jul-07 0:28

Peter, Chan wrote:
I define an array.How to calculate its length

Did you have a look at the sizeof()

Somethings seem HARD to do, until we know how to do them.
Wink | ;-)

_AnShUmAn_

Re: how to calculate an array's length?

Bram van Kampen3-Jul-07 15:23

Bram van Kampen

3-Jul-07 15:23

It depends on what you want. If the array is dynamically declared, i.e. You used 'malloc', there is no knowing, unless if you build in your own scheme of determining these things. At any rate, the size of the array is known to you, because you had to give the size to the malloc function. In these cases, you need to devine a scheme to pass this knowledge on to where it is needed.

in statically declared arrays, you can use the sizeof() operator to get the size of an array in bytes. But, still again, beware and look at the language definition.

i.e.:

char * Arr[]={"First Item","Second Item"};

This is an array of pointers to character strings. Arr contains two 4-Bit Items ( or 2 8-Bit items in a 64 bit Compiler), namely the Addresses of the two strings, "First Item" and "Second Item". So in the above example,
sizeof(ARR) would always give 8 ( or 16 in a 64 bit Compiler environment). If you need to know wat's needed to store the structure ans it's data, you need:-

size_t GetTotalDataSize(){
size_t NrOfItems= sizeof(Arr)/sizeof(char*);
size_t TotalSize=sizeof(Arr);
for(int i=0;i<NrOfItems;i++)TotalSize+=(strlen(Arr+i)+1);
return TotalSize;
}

LateNightsInNewry

Re: how to calculate an array's length?

Peter, Chan3-Jul-07 15:54

Peter, Chan

3-Jul-07 15:54

Your description is very clear. I now know clearly how to use sizeof().
I still just have one question.
Just as your sample.

char * Arr[]={"First Item","Second Item"};

Do I need to delete Arr when it is useless.

<br />
delete Arr[0];<br />
delete Arr[1];

Re: how to calculate an array's length?

Hans Dietrich4-Jul-07 1:38

Hans Dietrich

4-Jul-07 1:38

Peter, Chan wrote:
Do I need to delete Arr when it is useless.

In this case, no. Since you did not allocate the strings using new, you do not have to free them using delete.

Best wishes,
Hans

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Using SetWindowRgn on bitmap buttons

mcsherry2-Jul-07 23:52

mcsherry

2-Jul-07 23:52

I've got a bitmap on a button and I want the user to be only able to click the area of the button that is covered by the bitmap.
For circular bitmaps I've used the following code:

CRect button_rect ; // size of button
HRGN rgn ;

button->GetClientRect ( &button_rect ) ;

rgn = CreateEllipticRgn( 0,
                         0,
                         button_rect.Width(),
                         button_rect.Height() );

button->SetWindowRgn ( rgn,
                       TRUE ) ;

However I've got a bitmap that has a rectangle that is diagonal across the bitmap, does anyone know how I can create a HRGN object with the points for the diagonal rectangle.

TIA,

Re: Using SetWindowRgn on bitmap buttons

khan++3-Jul-07 0:33

khan++

3-Jul-07 0:33

I think you can use CreatePolygonRgn(...)

Also, you can use the CRgn wrapper instead of HRGN:

CRgn rgn;<br />
CPoint pt[3];<br />
pt[0].x = 10;<br />
pt[0].y = 10;<br />
pt[1].x = 100;<br />
pt[1].y = 100;<br />
pt[2].x = 10;<br />
pt[2].y = 100;<br />
<br />
rgn.CreatePolygonRgn(pt,3,ALTERNATE);

this is this.

Re: Using SetWindowRgn on bitmap buttons

mcsherry3-Jul-07 2:48

mcsherry

3-Jul-07 2:48

thanks for your reply, got it semi working using this just need to get my polygon region the right shape/size now!

cheers,

Getting SACL & Privilege Problem

Akin Ocal2-Jul-07 23:44

Akin Ocal

2-Jul-07 23:44

I cant get SACL structure of a file , however i call a function : Privilege(SE_SECURITY_NAME,TRUE);

How can i get sacl ??

BOOL Privilege(LPTSTR pszPrivilege, BOOL bEnable)
{
HANDLE hToken;
TOKEN_PRIVILEGES tp;

//
// obtain the token, first check the thread and then the process
//
if (!OpenThreadToken(GetCurrentThread(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, TRUE, &hToken)){
if (GetLastError() == ERROR_NO_TOKEN){
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken))
return FALSE;
}
else
return FALSE;
}

//
// get the luid for the privilege
//
if (!LookupPrivilegeValue(NULL, pszPrivilege, &tp.Privileges[0].Luid))
return FALSE;

tp.PrivilegeCount = 1;

if (bEnable)
tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
else
tp.Privileges[0].Attributes = 0;

//
// enable or disable the privilege
//
if (!AdjustTokenPrivileges(hToken, FALSE, &tp, 0, (PTOKEN_PRIVILEGES)NULL, 0))
return FALSE;

if (!CloseHandle(hToken))
return FALSE;

return TRUE;
}

Cleaning up a struct

Programm3r2-Jul-07 23:37

Programm3r

2-Jul-07 23:37

Hi all,

Lets say one has a struct like: And this struct has data in it. Is it possible to empty the struct without using a loop (to clear out each of the variables data in the struct?)

#define BUF_SIZE 100
struct fee
{
   char bufOne[128];
   char bufTwo[128];
}FOO[BUF_SIZE];

Many Thanks
Regards,

The only programmers that are better that C programmers are those who code in 1's and 0's Green Alien | [Alien]

Programm3r
My Blog: ^_^

Re: Cleaning up a struct

MANISH RASTOGI2-Jul-07 23:46

MANISH RASTOGI

2-Jul-07 23:46

::ZeroMemory(&Foo[0], sizeof(fee) * BUF_SIZE);
or
memset(&FOO[0], 0, sizeof(fee) * BUF_SIZE);

Manish Rastogi

Re: Cleaning up a struct

Programm3r2-Jul-07 23:51

Programm3r

2-Jul-07 23:51

manish rastogi wrote:
::ZeroMemory(&Foo[0], sizeof(fee) * BUF_SIZE);
or
memset(&FOO[0], 0, sizeof(fee) * BUF_SIZE);

Thanks for the response ..

Q: Would that clear the entire struct and all of it's members?

Regards,

The only programmers that are better that C programmers are those who code in 1's and 0's Green Alien | [Alien]

Programm3r
My Blog: ^_^

Re: Cleaning up a struct

MANISH RASTOGI3-Jul-07 0:55

MANISH RASTOGI

3-Jul-07 0:55

Yes.

Re: Cleaning up a struct

Programm3r3-Jul-07 0:58

Programm3r

3-Jul-07 0:58

Thanks

The only programmers that are better that C programmers are those who code in 1's and 0's Green Alien | [Alien]

Programm3r
My Blog: ^_^

Re: Cleaning up a struct

Hans Dietrich3-Jul-07 0:12

Hans Dietrich

3-Jul-07 0:12

memset(FOO, 0, sizeof(FOO));

Best wishes,
Hans

[CodeProject Forum Guidelines] [How To Ask A Question] [My Articles]

Re: Cleaning up a struct

Programm3r3-Jul-07 0:13

Programm3r

3-Jul-07 0:13

Thanks Hans Smile | :)

...

Regards,

The only programmers that are better that C programmers are those who code in 1's and 0's Green Alien | [Alien]

Programm3r
My Blog: ^_^

Is it possible to modify the systray clock menu?

mid=57412-Jul-07 23:33

mid=5741

2-Jul-07 23:33

I would like to modify the menu that pops up when the mouse is right-clicked on the clock in the system tray. I want to add another entry below "Customize Notifications..." in the menu. Is this possible? If so, please point me in the right direction.

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