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  • What language has the longest "Hello world" program?

    - by Kip
    In most scripting languages, a "Hello world!" application is very short: print "Hello world" In C++, it is a little more complicated, requiring at least 46 non-whitespace characters: #include <cstdio> int main() { puts("Hello world"); } Java, at 75 non-whitespace characters, is even more verbose: class A { public static void main(String[] args) { System.out.print("Hello world"); } } Are there any languages that require even more non-whitespace characters than Java? Which language requires the most? Notes: I'm asking about the length of the shortest possible "hello world" application in a given language. A newline after "Hello world" is not required. I'm not counting whitespace, but I know there is some language that uses only whitespace characters. If you use that one you can count the whitespace characters.

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  • Managing Cisco programatically; Telnet vs SNMP?

    - by MikeHerrera
    I was recently approached by a network-engineer, co-worker who would like to offload his minor network admin duties to a junior-level helpdesk tech. The specific location in need of management acts as an ISP for tenants on its single-site property, so there's a lot of small adjustments being made on a daily basis. I am thinking it would be helpful to write him a winform app to manage the 32 Cisco devices, on-site. I'd like to initially provide functionality which could modify access control lists, port VLAN assignments, and bandwidth limitations per VLAN... adding more to the list as its deemed valuable. My initial thought was to emulate a telnet session with the network device; utilizing my network-engineer's familiarity with the command-line / IOS interaction. Minimal time would be required to learn Cisco IOS conventions, myself. Though while searching for solutions, it appears that most people favor SNMP. That, or, their specific circumstances pushed them in the direction of SNMP. I wanted to know if I've overlooked an obvious benefit of SNMP. Should I be using SNMP? Why or why not?

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  • Receiving broadcast messages

    - by Prasad
    Hi, I'm trying to receive broadcast messages using C# code in an ISDN network with BRI interface at my end. I see the packets sent to the broadcast ip address (239.255.255.255) on some ports using Comm View tool. But when I try to listen to this IP address, it says the address is not in a valid context. But when I send broadcast messages to 255.255.255.255 on a port, I can receive those messages with the below code.. What could be the problem with this ip address - 239.255.255.255 ? The code I use to listen to broadcast messages is.. UdpClient udp = new UdpClient(); IPEndPoint receiveEndPoint = new IPEndPoint(IPAddress.Any, 8013); // If I use IPAddress.Parse("239.255.255.255") to listen to, // it says "the address is not in a valid // context." udp.Client.Bind(receiveEndPoint); udp.BeginReceive(_Callback, udp); static private void _Callback(IAsyncResult iar) { try { UdpClient client = (UdpClient)iar.AsyncState; client.BeginReceive(_Callback, client); IPEndPoint ipRemote = new IPEndPoint(IPAddress.Any, 8013); byte[] rgb = client.EndReceive(iar, ref ipRemote); Console.WriteLine("Received {0} bytes: \"{1}\"", rgb.Length.ToString(), Encoding.UTF8.GetString(rgb)); } catch (ObjectDisposedException) { Console.WriteLine("closing listening socket"); } catch (Exception exc) { Console.WriteLine("Listening socket error: \"" + exc.Message + "\""); } } There are packets sent to the broadcast ipaddress (239.255.255.255) which I can see in Commview tool, but can't receive them from the code... Can anybody help me out please? Thanking you in advance, Prasad Kancharla.

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  • Auto switching databases from a rails app gracefully from the ApplicationController?

    - by Zaqintosh
    I've seen this post a few times, but haven't really found the answer to this specific question. I'd like to run a rails application that based on the detected request.host (imagine I have two subdomains points to the same rails app and server ip address: myapp1.domain.com and myapp2.domain.com). I'm trying to have myapp1 use the default "production" database, and myapp2 requests always use the alternative remote database. Here is an example of what I tried to do in Application controller that did not work: class ApplicationController < ActionController::Base helper :all before_filter :use_alternate_db private def use_alternate_db if request.host == 'myapp1.domain.com' regular_db elsif request.host == 'myapp2.domain.com' alternate_db end end def regular_db ActiveRecord::Base.establish_connection :production end def alternate_db ActiveRecord::Base.establish_connection( :adapter => 'mysql', :host => '...', :username => '...', :password => '...', :database => 'alternatedb' ) end end The problem is when it switches databases using this method, all connections (including valid sessions across the different subdomains get interrupted...). All examples online have people controlling database connectivity at the model level, but this would involve adding code all over my application. Is there some way to globally switch database connections on a per-request basis in the manner I'm suggesting above WITHOUT having to inject code all over my application? The added complexity here is I'm using Heroku as a hosting provider, so I have no control at the apache / rails application server level. I have looked at solutions like dbcharmer and magicmodels, but none seem to show examples of doing it in the manner that I'm trying to. Thanks for any help!

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  • Forking with Pipes

    - by Luke
    Hello I have tried to do fork() and piping in main and it works perfectly fine but when I try to implement it in a function for some reason I don't get any output, this is my code: void cmd(int **pipefd,int count,int type, int last); int main(int argc, char *argv[]) { int pipefd[3][2]; int i, total_cmds = 3,count = 0; int in = 1; for(i = 0; i < total_cmds;i++){ pipe(pipefd[count++]); cmd(pipefd,count,i,0); } /*Last Command*/ cmd(pipefd,count,i,1); exit(EXIT_SUCCESS); } void cmd(int **pipefd,int count,int type, int last){ int child_pid,i,i2; if ((child_pid = fork()) == 0) { if(count == 1){ dup2(pipefd[count-1][1],1); /*first command*/ } else if(last!=0){ dup2(pipefd[count - 2][0],0); /*middle commands*/ dup2(pipefd[count - 1][1],1); } else if(last == 1){ dup2(pipefd[count - 1][0],0); /*last command*/ } for(i = 0; i < count;i++){/*close pipes*/ for(i2 = 0; i2 < 2;i2++){ close(pipefd[i][i2]); }} if(type == 0){ execlp("ls","ls","-al",NULL); } else if(type == 1){ execlp("grep","grep",".bak",NULL); } else if(type==2){ execl("/usr/bin/wc","wc",NULL); } else if(type ==3){ execl("/usr/bin/wc","wc","-l",NULL); } perror("exec"); exit(EXIT_FAILURE); } else if (child_pid < 0) { perror("fork"); exit(EXIT_FAILURE); } } I checked the file descriptors and it is opening the right ones, not sure what the problem could be..

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  • What are your recommended tools and frameworks for network development on Linux?

    - by Vivek Sharma
    What are your favourite network-tools, which you use to troubleshoot or design (as in conceptualize) your network-application code. Ethereal/Wireshark Nmap any particular simulators (e.g. ns) any special purpose sniffer any particular frameworks, (e.g. iptables) I am looking at must have, and good/advantage to have tools/framework in ones profile/skill set. I think Wireshark and Nmap are must haves.

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  • touchesBegin & touchesMove Xcode Obj C Question

    - by AndrewDK
    So I have my app working good when you press and drag along. I also have UIButtons set to Touch Down in Interface Builder. As well when you drag you need to drag from the outside of the UIButton. You cannot click on the UIButton and drag to the other. TOUCHES MOVED: Code: -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [[event touchesForView:self.view] anyObject]; CGPoint location = [touch locationInView:touch.view]; if(CGRectContainsPoint(oneButton.frame, location)) { if (!oneButton.isHighlighted){ [self oneFunction]; [oneButton setHighlighted:YES]; } }else { [oneButton setHighlighted:NO]; } // if(CGRectContainsPoint(twoButton.frame, location)) { if (!twoButton.isHighlighted){ [self twoFunction]; [twoButton setHighlighted:YES]; } }else { [twoButton setHighlighted:NO]; } } TOUCHES BEGAN: Code: - (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [[event touchesForView:self.view] anyObject]; CGPoint location = [touch locationInView:touch.view]; if(CGRectContainsPoint(oneButton.frame, location)) { [self oneFunction]; [oneButton setHighlighted:YES]; } if(CGRectContainsPoint(twoButton.frame, location)) { [self twoFunction]; [twoButton setHighlighted:YES]; } } I want to be able to click on any of the button fire the function & also be able to drag from one button on to the other and fire that function. So basically just being able to click on a button and slide your finger over and activate the other button without having to press and slide from outside of the button. I think I'm close, need a bit of help. Hope thats clear enough. Thanks.

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  • Filter items from a feed using words in a text file, with Yahoo Pipes

    - by pufferfish
    I have a pipe that filters an RSS feed and removes any item that contains "stopwords" that I've chosen. Currently I've manually created a filter for each stopword in the pipe editor, but the more logical way is to read these from a file. I've figured out how to read the stopwords out of the text file, but how do I apply the filter operator to the feed, once for every stopword? The documentation states explicitly that operators can't be applied within the loop construct, but hopefully I'm missing something here.

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  • perl multiple tasks problem

    - by Alice Wozownik
    I have finished my earlier multithreaded program that uses perl threads and it works on my system. The problem is that on some systems that it needs to run on, thread support is not compiled into perl and I cannot install additional packages. I therefore need to use something other than threads, and I am moving my code to using fork(). This works on my windows system in starting the subtasks. A few problems: How to determine when the child process exits? I created new threads when the thread count was below a certain value, I need to keep track of how many threads are running. For processes, how do I know when one exits so I can keep track of how many exist at the time, incrementing a counter when one is created and decrementing when one exits? Is file I/O using handles obtained with OPEN when opened by the parent process safe in the child process? I need to append to a file for each of the child processes, is this safe on unix as well. Is there any alternative to fork and threads? I tried use Parallel::ForkManager, but that isn't installed on my system (use Parallel::ForkManager; gave an error) and I absolutely require that my perl script work on all unix/windows systems without installing any additional modules.

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  • NVIDIA CUDA SDK Examples Compilation Unsupported Architecture 'computer_20'

    - by Andrew Bolster
    On compilation of the CUDA SDK, I'm getting a nvcc fatal : Unsupported gpu architecture 'compute_20' My toolkit is 2.3 and on a shared system (i.e cant really upgrade) and the driver version is also 2.3, running on 4 Tesla C1060s If it helps, the problem is being called in radixsort. It appears that a few people online have had this problem but i havent found anywhere that actually gives a solution.

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  • Storing VMware virtual machines in external harddisk

    - by Jeffery Ang
    Any issue with that? I recently setup ubunutu virtual machine on my external harddisk. Once i accidentally removed the external harddisk usb connection then when i try to startup the ubuntu virtual machine again i get kernel panic. I thinking of writing a cron script to backup everyday to another location to prevent this issue

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  • Efficient Map Overlays in and drawing Lines on Android Google Map...

    - by Ahsan
    Hi Friends, I want to do the following and am kind of stuck on these for a few days.... 1) I have used helloItemizedOverlay to add about 150 markers and it gets very very slow.....any idea what to do ? I was thinking about threads....(handler) ... 2) I was trying to draw poly lines ( I have encoded polylines, but have managed to decoded those) that move when I move the map..... 3) I was looking for some sort of a timer class that executes, say, every 1 minute or so.... 4) I was also looking for ways to clear the Google map from all the markers/lines etc.... Thanks a lot... :) - ahsan

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  • Novel fitness measure for evolutionary image matching simulation

    - by Nick Johnson
    I'm sure many people have already seen demos of using genetic algorithms to generate an image that matches a sample image. You start off with noise, and gradually it comes to resemble the target image more and more closely, until you have a more-or-less exact duplicate. All of the examples I've seen, however, use a fairly straightforward pixel-by-pixel comparison, resulting in a fairly predictable 'fade in' of the final image. What I'm looking for is something more novel: A fitness measure that comes closer to what we see as 'similar' than the naive approach. I don't have a specific result in mind - I'm just looking for something more 'interesting' than the default. Suggestions?

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  • Create a VPN with Python

    - by user213060
    I want to make a device "tunnel box" that you plug an input ethernet line, and an output ethernet line, and all the traffic that goes through it gets modified in a special way. This is similar to how a firewall, IDS, VPN, or similar boxes are connected inline in a network. I think you can just assume that I am writing a custom VPN in Python for the purpose of this question: LAN computer <--\ LAN computer <---> [LAN switch] <--> ["tunnel box"] <--> [internet modem] <--> LAN computer <--/ My question is, what is a good way to program this "tunnel box" from python? My application needs to see TCP flows at the network layer, not as individual ethernet frames. Non-TCP/IP traffic such as ICPM and other types should just be passed through. Example Twisted-like Code for my "tunnel box" tunnel appliance: from my_code import special_data_conversion_function class StreamInterceptor(twisted.Protocol): def dataReceived(self,data): data=special_data_conversion_function(data) self.outbound_connection.send(data) My initial guesses: TUN/TAP with twisted.pair.tuntap.py - Problem: This seems to only work at the ethernet frame level, not like my example? Socks proxy - Problem: Not transparent as in my diagram. Programs have to be specifically setup for it. Thanks!

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  • sendto: Invalid Argument

    - by Sylvain
    Hi, I have a list<struct sockaddr_in> _peers I'd like to use for sendto() the list is filled this way struct hostent *hp; hp = gethostbyname(hostname); sockaddr_in sin; bzero(&sin, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_port = htons(port); sin.sin_addr.s_addr = *(in_addr_t *)hp->h_addr; _peers.push_front(sin); and here's how I try to send: for (list<struct sockaddr_in>::iterator it = _peers.begin(); it != _peers.end(); ++it) { if (sendto(_s, "PING", 5, 0, (struct sockaddr *)&(*it), sizeof(struct sockaddr_in)) < 0) perror("sendto"); } outputs: sendto: Invalid argument If I create the struct sockaddr_in right before sendto(), everything works fine, so I guess I fail at using the list properly ... I also tested using &_peers.front() directly and still get the same error ... what am I doing wrong? Thanks in advance,

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  • cartesian product

    - by John Retallack
    I've been trying to do a function that returns the Cartesian Product of n sets,in Dr Scheme,the sets are given as a list of lists,I've been stuck at this all day,I would like a few guidelines as where to start,I've wrote a pice of code but it dosen't work. (define cart-n(?(l) (if (null? l) '(()) (map (?(lst) (cons (car ( car(l))) lst)) (cart-n (cdr l) )))))

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  • Data Transfer Objects VS Domain/ActiveRecord Entities in the View in RoR

    - by leypascua
    I'm coming from a .NET background, where it is a practice to not bind domain/entity models directly to the view in not-so-basic CRUD-ish applications where the view does not directly project entity fields as-is. I'm wondering what's the practice in RoR, where the default persistence mechanism is ActiveRecord. I would assert that presentation-related info should not be leaked to the entities, not sure though if this is how real RoR heads would do it. If DTOs/model per view is the approach, how will you do it in Rails? Your thoughts? EDIT: Some examples: - A view shows a list of invoices, with the number of unique items in one column. - A list of credit card accounts, where possibly fraudulent transactions were executed. For that, the UI needs to show this row in red. For both scenarios, The lists don't show all of the fields of the entities, just a few to show in the list (like invoice #, transaction date, name of the account, the amount of the transaction) For the invoice example, The invoice entity doesn't have a field "No. of line items" mapped on it. The database has not been denormalized for perf reasons and it will be computed during query time using aggregate functions. For the credit card accounts example, surely the card transaction entity doesn't have a "Show-in-red" or "IsFraudulent" invariant. Yes it may be a business rule, but for this example, that is a presentation concern, so I would like to keep it out of my domain model.

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  • OT: US Banks: Bank Routing Number and BIC/SWIFT

    - by Konerak
    I know it is a bit offtopic, but I've been having a hard time finding more information to this question, and since this site is visited by a lot of people from the United States, you guys might know/find the answer more easily. Banks in europe each have a SWIFT Number, while US Banks use Routing Numbers. This leads to following questions: Does each bank in the US also carry a BIC number? (SWIFT) Is there a 1-1 relationship between BIC and SWIFT? Is there a list of these numbers somewhere? (background information: we're adding international payments to our bookkeeping application. Users can add international suppliers, but my boss prefered not to change the current supplier table but to have the ROUTING NUMBER in another table, with as PK the BIC. I'm wondering if BIC is a valid choice, or if it should just be BANK ACCOUNT NUMBER.)

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  • Microsoft Quotation

    - by Asad Jibran Ahmed
    I don't know if this is the right place to ask this question, but I honestly have exhausted my self searching for the last hour. I am looking for a quotation made about Microsofts software. It goes something along the lines of: "They may make 2nd grade crappy software, but by God they know how to design interfaces" It was by a somewhat popular open source personality about the lack of good interface design in open source software. Does any one know the exact quotation? It will be a great help if someone can point me in the right direction.

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  • Linq Query Performance , comparing Compiled query vs Non-Compiled.

    - by AG.
    Hello Guys, I was wondering if i extract the common where clause query into a common expression would it make my query much faster, if i have say something like 10 linq queries on a collection with exact same 1st part of the where clause. I have done a small example to explain a bit more . public class Person { public string First { get; set; } public string Last { get; set; } public int Age { get; set; } public String Born { get; set; } public string Living { get; set; } } public sealed class PersonDetails : List<Person> { } PersonDetails d = new PersonDetails(); d.Add(new Person() {Age = 29, Born = "Timbuk Tu", First = "Joe", Last = "Bloggs", Living = "London"}); d.Add(new Person() { Age = 29, Born = "Timbuk Tu", First = "Foo", Last = "Bar", Living = "NewYork" }); Expression<Func<Person, bool>> exp = (a) => a.Age == 29; Func<Person, bool> commonQuery = exp.Compile(); var lx = from y in d where commonQuery.Invoke(y) && y.Living == "London" select y; var bx = from y in d where y.Age == 29 && y.Living == "NewYork" select y; Console.WriteLine("All Details {0}, {1}, {2}, {3}, {4}", lx.Single().Age, lx.Single().First , lx.Single().Last, lx.Single().Living, lx.Single().Born ); Console.WriteLine("All Details {0}, {1}, {2}, {3}, {4}", bx.Single().Age, bx.Single().First, bx.Single().Last, bx.Single().Living, bx.Single().Born); So can some of the guru's here give me some advice if it would be a good practice to write query like var lx = "Linq Expression " or var bx = "Linq Expression" ? Any inputs would be highly appreciated. Thanks, AG

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