C / C++ / MFC

<<NEWB-Troubles with stacks

25-Mar-05 16:02

The theoretical limit is 2GB per process.

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

Re: Memory Limits

Obi Wan 225-Mar-05 17:21

Obi Wan 2

25-Mar-05 17:21

Thanks...this is consistent with my observations.

-Obi Wan 2

Restart the process

mpapeo25-Mar-05 13:38

mpapeo

25-Mar-05 13:38

Hello,
I have a problem in my C program code. I want to restart or recreate a process which was suspended and its state was saved in a binary file and then terminated. Now i want to recreate/restart it using its previous state.
I tried to use the functions below but it seems the functions do not work.
Help me please, part of my code:

<br />
case 6://restarting the process <br />
lpBaseAddress = 0;<br />
hProcess = mbi.BaseAddress;<br />
SetThreadContext( <br />
hThread, <br />
lpContext <br />
);<br />
  WriteProcessMemory(<br />
  hProcess,	// handle to process whose memory is written to   lpBaseAddress,   // address to start writing to<br />
lpBuffer,				// pointer to buffer to write data to<br />
nSize,					// number of bytes to write<br />
lpNumberOfBytesWritten  // actual number of bytes written<br />
);<br />
ResumeThread(pi.hThread);// identifies thread to restart<br />
GetLastError();<br />
break;<br />

what am i missing here, or i have to call the createprocess() function again?

oam

Re: Restart the process

Anand for every one25-Mar-05 21:41

Anand for every one

25-Mar-05 21:41

See you said you terminated the process. Then how can you resume it ?
Only Suspended process can Resumed. Not Terminated Process.
You should not terminate it.Just Suspend it.

Re: Restart the process

mpapeo26-Mar-05 9:00

mpapeo

26-Mar-05 9:00

In process migration, there should be a way of restarting a suspended process(check pointed process) in the other machine on the network. Ifact i want to used the saved process information like baseaddress, context e.t.c after it was suspended. So there should be a possible way. But the big question how????

oam

ActiveX in C++

j1webb25-Mar-05 12:36

j1webb

25-Mar-05 12:36

I wrote some MSDOS programs in C++ many years ago (Borland's C++) and so I'm not very knowledgeable about the current Visual C++, but here is what I want to do and it doesn't seem like it should be too difficult.

I have a web site that displays a table of records and each line has a microphone icon on it. When the user clicks on that mic icon another web page is opened and it tells the user they may create a dictation. (We have special dictation mics running from a vb.net app that runs from the user's local machine.) We also have an image display program running at the same time and it also runs from the user's machine.

The web app knows what the StudyID is but the vb.net apps don't and I need to be able to pass that StudyID to the local machine so it can be used by the image display program to find the correct images to display while the user is dictating.

I wrote a "faux" activeX (dll) in vb.net that could be placed on the web site and run when the 2nd page is displayed and the studyID could be passed to it and then it would use the study ID and the Process class to cause the image display program to display the correct images, but that would require each user's machine to have the correct security manually setup in .Net Configuration and we don't want to have to do that. So I thought maybe an ActiveX written in C++ could basically do the same thing.

Does this make sense? Could this be done and if so, would it be as easily done as I think it might be.

rdt25325-Mar-05 11:48

rdt253

25-Mar-05 11:48

I'm having trouble figuring out what to do with this program...any help would be greatly appreciated
Cheers!

Write a program that prompts for a file name and then reads the file to
check for balanced curly braces, {}; parentheses, (); and square brackets,
[]. Use a stack to store the most recent unmatched left symbol. The program
should ignore character that is not a parenthesis, curly brace, or square
bracket. Note that proper nesting is required. For instance, [a(b]c) is
invalid.
Sample runs:
Output
1. {{a+5}-7*[1-{4/2}]}/{2*(3-6)} Valid
2. {(a+5)-7*[1-{4/2}])/{2*(3-6)} Invalid

Paul M Watt25-Mar-05 12:56

Paul M Watt

25-Mar-05 12:56

It sounds like the purpose is for you to write a stack class then use it. Your C++ book should describe the operations.

First you need to write a stack class.

Then while scanning the file, when ever you see a left { or [, you should push that character on the stack, and when you see a } or a ], you should check the top of the stack to see if the item that would be popped off is the same as the value you are comparing against. If it is the same, pop it off and continue scanning, otherwise the pairs are mismatched and you have invalid data.

When you get to the end of the file, the stack should be empty, if not, then you also have invalid data.

Good Luck

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

FlyingTinman25-Mar-05 13:05

FlyingTinman

25-Mar-05 13:05

Decare a CString variable to be your "stack" (or a CArray of type char )

Initialize it to be empty.

Write a function : void Push(char) which adds one character to the end of the CString.
Write a function : char Pop() which returns the character at the end of the CString then removes it (or returns an error value if the string is empty)

Now write a main loop that read in chars from your file one at a time.
1) If it finds a left brace, paren or bracket it must call Push(char) and add it to the string
2) If it finds a right brace, paren or bracket it must call Pop() and compare the result to the char just read in.
3) If it finds any other character ignore it keep looping :

In case 2) (right symbol read in from file)
If Pop() returns a matching left symbol it can carry on looping.
If Pop() returns a non-matching left symbol then the input was invalid.
If Pop() returns the error value because the CString is empty then the input was invalid.

If your reach the end of file with no previos fail:
Call Pop() and check for the error value (CString empty)
If the CString (your stack) is empty (Pop() returns error value) the input was valid.
If the CString (your stack) is not empty the input was invalid.

[edit]
I suggested the CString or CArray so you don't have to worry about memory management as the stack (whose max required size will be unknown) grows: If the exercise is intended to demonstrate your ability to allocate and free memory dynamically then you will need to use char* instead of CString/CArray and allocate an initial amount of memory for the stack and each time you add a char check to see if it needs more allocated.
[/edit]

Steve T

rdt25325-Mar-05 15:42

rdt253

25-Mar-05 15:42

Ok, this is pretty much what i have so far....it works on some cases...but when i try to implement other strings, it gives me errors...here is the code i have so far...

<br />
#include <stack><br />
#include <fstream><br />
#include <iostream><br />
<br />
<br />
using namespace std;<br />
<br />
int main()<br />
{<br />
	<br />
	stack<char> charStack;<br />
	<br />
	char cChar;<br />
		<br />
	ifstream inFile;<br />
	<br />
	<br />
	inFile.open("infile.txt");  <br />
	<br />
	if(!inFile)                <br />
	{<br />
		cout<<"Input file does not exist."<<endl;<br />
		return 1;<br />
	}<br />
	<br />
		inFile>>cChar;<br />
	<br />
	while(inFile)<br />
	{<br />
				<br />
		if (cChar == '{' || cChar == '[' || cChar == '(')<br />
		{<br />
			charStack.push(cChar);<br />
		}<br />
		<br />
		else<br />
		{<br />
			if (charStack.top() == '(')<br />
			{<br />
				if (cChar == ')')<br />
				{<br />
				charStack.pop();<br />
				}<br />
			}<br />
			else if (charStack.top() == '[')<br />
			{<br />
				if(cChar == ']')<br />
				{<br />
					charStack.pop();<br />
				}<br />
			}<br />
			else if (charStack.top() == '{')<br />
			{<br />
				if(cChar == '}')<br />
				{<br />
					charStack.pop();<br />
				}<br />
			}<br />
		}<br />
		<br />
<br />
		inFile>>cChar;<br />
	}<br />
<br />
	if(charStack.empty()) <br />
	{<br />
		cout<<endl<<"Valid"<<endl;<br />
	}<br />
	<br />
	else <br />
	{<br />
		cout<<endl<<"Invalid"<<endl;<br />
	}<br />
	<br />
<br />
	cin.get();<br />
<br />
return 0;<br />
<br />
}<br />
<br />

when i use these input files, I get a valid output....

<br />
input:<br />
{(a+5)-7*[1-{4/2}])/{2*(3-6)} //invalid<br />
<br />
input:<br />
(((({[]})()()))){} //valid<br />
<br />
input:<br />
{{()}  //invalid<br />

and i get errors on the following

<br />
input:<br />
{()[()]}} <br />
<br />
input:<br />
{{a+5}-7*[1-{4/2}]}/{2*(3-6)}<br />

HELP!!!

David Crow25-Mar-05 16:03

25-Mar-05 16:03

rdt253 wrote:
and i get errors...

What errors?

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

rdt25325-Mar-05 16:11

rdt253

25-Mar-05 16:11

I dont get any compile errors...but when I run stack.exe i get a windows error "stack.exe has encountered a problem and needs to close. We are sorry for the inconvenience. It then prompts me to debug, send error report, or ignore error report...

David Crow26-Mar-05 7:07

Accessing and displaying data of worker thread function

26-Mar-05 7:07

Step through the program one statement at a time...until it "crashes."

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

Member 153706925-Mar-05 11:11

Member 1537069

25-Mar-05 11:11

Hi,

I'm working on a GUI interface that has worker theads. I want to be able to access data generated from the worker thread and display it on the GUI in real time. Right now, i'm able to access the data but I'm not able to display it until the thread finishes. Is there a way to access the data and display it in real time while the thread is running?

Thanks

Lien

Re: Accessing and displaying data of worker thread function

Paul M Watt25-Mar-05 12:59

Paul M Watt

25-Mar-05 12:59

What is preventing you from displaying it until after the worker thread has finished?

Is your UI thread waiting for the worker thread to finish? Are you storing your data on the worker thread in buffers that are accessible to the UI thread? What kind of data do you have, and how are you trying to display it on the UI?

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: Accessing and displaying data of worker thread function

PJ Arends25-Mar-05 13:04

PJ Arends

25-Mar-05 13:04

Two ideas:
1- Have your worker thread post user messages to your GUI thread informing it about the current status.

2- Use a data structure that your worker thread and GUI thread both have access to. Be careful about data access synchronisation when using this approach.

"You're obviously a superstar." - Christian Graus about me - 12 Feb '03

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Saving Bitmap From Clipboard to file

ww303125-Mar-05 8:18

ww3031

25-Mar-05 8:18

Hi.. anyone help with some info to save a bitmap from the clipboard into a bitmap file?

Re: Saving Bitmap From Clipboard to file

David Crow25-Mar-05 9:21

Re: Saving Bitmap From Clipboard to file

25-Mar-05 9:21

if (OpenClipboard(NULL) != FALSE)
{
    HBITMAP hBitmap = GetClipboardData(CF_BITMAP);
    if (NULL != hBitmap)
    {
        // see <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/bitmaps_7zfp.asp" rel="nofollow">here</a>
    }

    CloseClipboard();
}

[edit]
I just tried this and it works fine.
[/edit]

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

ww303125-Mar-05 11:01

ww3031

25-Mar-05 11:01

Thanks

VC++ 2003 .NET

victorsk25-Mar-05 7:27

victorsk

25-Mar-05 7:27

Hello,

I am thinking of getting either a VC++ 2003 .NET or VC++ 6. I have to write an FTP application that would work on the internet. I will very much appreciate if somebody could tell me what would be the best platform for this application: VC++ 2003 .NET or VC++ 6? And, if it is VC++ 2003, could somebody please tell me how adding handlers works in this platform?

Thank you,
Victor.

Kevin McFarlane25-Mar-05 10:16

Kevin McFarlane

25-Mar-05 10:16

You may as well get the more up-to-date version. VC++ 2003 will do everything that VC++ 6 does plus more.

If you intend to use MFC then you should be aware that ClassWizard is no longer present but the online help explains how to add event handlers. Many think that the new way is less usable than the old way but, nevertheless, the functionality and features of the framework, as opposed to the IDE, are richer.

Kevin

victorsk25-Mar-05 11:00

victorsk

25-Mar-05 11:00

Hi Kevin,

Thank you very much for the reply. I think I will get VC++ 2003.

Victor.

Kevin McFarlane25-Mar-05 11:08

Kevin McFarlane

25-Mar-05 11:08

You might want to investigate the differences between the Standard and Professional editions though. You can get the Standard Edition by itself. But for the Professional Edition, you have to purchase the entire Visual Studio 2003 (or use the free command line compiler with no IDE! Cry | :((

). I don't know whether this is an issue for you or not. I'm not entirely sure what you lose if you just get VC++ 2003 Standard but I'm sure there must be a feature matrix somewhere.

Kevin