Visual Basic

Multipling two large intergers

21-Apr-07 7:00

n_gchaitra wrote:
what might be the reason for error?

How are we supposed to know if you don't supply the error message? A snippet of the code you're using would also help.

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Aptiva Dave20-Apr-07 15:01

Aptiva Dave

20-Apr-07 15:01

I need to multiply two integers that contain more than the 19 digit limit for long integer variables. At first I thought that I could place both numbers into an array list with each digit occupying a separate places in the array. And while that seems like a good way to get around the whole overflow problem, it still doesn't work because I wouldn't have a place to put the answer while I'm computing it.

It seems like it should be a simple answer to the problem, but I think that I am over thinking. Anyone with any kind of idea on answering this?

Re: Multipling two large intergers

TwoFaced20-Apr-07 19:21

TwoFaced

20-Apr-07 19:21

Couldn't you just use decimal instead.

Re: Multipling two large intergers

Dave Kreskowiak21-Apr-07 6:58

Re: Multipling two large intergers

21-Apr-07 6:58

Yeah, the Decimal type will handle this for you.

Or, if you wait until .NET 3.5, there's a built in BigInteger type you can use that'll work with integers of unlimited size, up to available memory of course.

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Aptiva Dave21-Apr-07 18:32

Aptiva Dave

21-Apr-07 18:32

You know, that might work. It is an assignment for a ASP.Net 2.0 class where we are writing web services. My professor just says long integers are limited but how would you multiply two of them. I'll try that, maybe.

Thanks

help with free twain software

JustmeNick20-Apr-07 13:07

JustmeNick

20-Apr-07 13:07

Hey,

I am working on this project that requires me to save a picture/jpeg to a folder from a scanner.
I have download many twain software to help in the process, but with these software i am unable to complied my program and use it else where because these twain dll are not free, they all needs registration code..i am using vintasoft twain.

here are my questions?

1. does anyone know where i could get twain dll library that allows me to save a jpeg image from a scanner and at the same time its free so i can complied it in my project?

2.Is there a better or easier way of doing this: that is saving an image from a scanner to a file?

3. Does anyone have the vintasoft activation code i could use?

I have found a vb.net sample code that doesn't use any twain dll, but the problem is that it was done in C# and not vb. If any one know how to convert it to vb, please send your email address so i can send it to you to be converted. I have tried online conversion programs..but didn't convert it properly.

Please help..

thanks.

Nab

Dave Kreskowiak20-Apr-07 13:27

20-Apr-07 13:27

JustmeNick wrote:
1. does anyone know where i could get twain dll library that allows me to save a jpeg image from a scanner and at the same time its free so i can complied it in my project?

Not that I've ever seen. Everything I've ever come acrossed costs $$$.

JustmeNick wrote:
2.Is there a better or easier way of doing this: that is saving an image from a scanner to a file?

Nope. You can't really tell the scanner to save to a file anyway. Without TWAIN or something like the generic Windows Image Aquisition Interface (WIA), you couldn't tell the scanner to do anything anyway.

JustmeNick wrote:
3. Does anyone have the vintasoft activation code i could use?

You should be taken out and shot for even thinking of asking this question here, or anywhere else. Asking a bunch of developers to help you steal a piece of software? Developers that make their living selling software and you want them to help you steal it?? Mad | :mad:

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

JustmeNick20-Apr-07 16:22

JustmeNick

20-Apr-07 16:22

Man you are harsh...I am sorry for saying that..but could you help me, i need help..thats why i asked.

any suggestions on how to get it done?

Nab

Christian Graus20-Apr-07 20:14

Christian Graus

20-Apr-07 20:14

JustmeNick wrote:
thats why i asked

You asked because you have no ethics, and wanted to steal something.

The Atalasoft TWAIN library is $400 and does a great job, their support also rocks.

Dave Kreskowiak21-Apr-07 6:48

21-Apr-07 6:48

JustmeNick wrote:
Man you are harsh...I am sorry for saying that..but could you help me, i need help..thats why i asked.

THEN BUY IT! Harsh?! You asked for someones license key that they spent a ton of money on. This isn't harsh.

You haven't begun to see harsh until you've had the FBI in your face. How's that for harsh?

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

maz233128-Apr-07 18:42

maz2331

28-Apr-07 18:42

Dosadi has a free version of EzTwain Classic on thier website that works okay.

http://www.dosadi.com

Dave Kreskowiak29-Apr-07 3:36

29-Apr-07 3:36

Don't tell me. Reply to the OP. That way, he'll get an email notice that you replied.

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Building a DNS server

TomPanjer197420-Apr-07 10:41

TomPanjer1974

20-Apr-07 10:41

Hi,

I'm currently developping an internet hotspot. This hotspot is connected to the internet by a cell-phone modem. Since this solution is used on passenger ships trough Europe, sometimes there is no connection to the internet. When this is the case, the hotspots clients will receive 'page cannot be displayed' errors. (the client can't reach the DNS server on the internet).

Right now I'm researching the possibility to write a DNS server, which normaly should forward all incomming request to another (internet) DNS server and return them to my clients. ONLY if there is no response from the forwarding DNS server, my DNS server should return a default address. On this address I will configure a webpage informing the clients about the current connection status.

If anybody has suggestions about this I would be glad to hear them.

Thanks in advance!

Kind regards,

Tom

Dave Kreskowiak20-Apr-07 13:23

20-Apr-07 13:23

You don't need your own DNS server. A Proxy server could do this though. Just about anything off-the-shelf would work and let you configure the error page.

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

TomPanjer197421-Apr-07 2:01

TomPanjer1974

21-Apr-07 2:01

Thank you for your reaction.

I'm aware of the possibilities of using a proxy server. The first version of my solution was in fact based on a proxy server. But there is one major problem with that approach. Since the clients are unknown users, I need to redirect them to a page where they can log in. Only after this, they are allowed to use the Internet. (the system is based on a radius server for authentication and accounting.) As far as I know, this isn't possible with a proxy server.
Authentication isn't a problem at all when using a proxy server, it is the redirection part that is quite hard to accomplish WITHOUT installing a proxy client or something like that.

It is my intention to have the clients use this hotspot without the need to install any software or having to make changes to their settings.

In fact, I have accomplished that part to my satisfaction. The only problem that remains is the problem that I described in my first post.

I think I need a multithreading server and a DNS component to reach my goal. In fact, all I want to do is forward all incomming DNS queries and return them to my clients. I only want to send a custom address when the forwarding server is unreachable.

Do you know of any project that is usable as a basis for this? I already found a DNS component for queriyng servers, but I still need something to listen / answer DNS requests.

Any comment would be usefull and appreciated.

Kind regards,

Tom.

Dave Kreskowiak21-Apr-07 6:54

21-Apr-07 6:54

TomPanjer1974 wrote:
it is the redirection part that is quite hard to accomplish WITHOUT installing a proxy client or something like that.

What client? This is stuff that's built into every web browser already. You don't need a client, just the configuration.

TomPanjer1974 wrote:
In fact, all I want to do is forward all incomming DNS queries and return them to my clients. I only want to send a custom address when the forwarding server is unreachable.

DNS servers already do this. but, they'll cache the fesults and pass the cached versions to the client if the upstream DNS isn't available. Now you run into the same problem. The DNS server doesn't care that the web page isn't available, but a proxy server does. Thats why i said this could be done using the proxy. If the page isn't available, it'll send down either a standard 400 or 500 error page or a custom one which you supply, like your status page.

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007