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  • Secure Copy File from remote server via scp and os module in Python

    - by user1063572
    I'm pretty new to Python and programming. I'm trying to copy a file between two computers via a python script. However the code os.system("ssh " + hostname + " scp " + filepath + " " + user + "@" + localhost + ":" cwd) won't work. I think it needs a password, as descriped in How do I copy a file to a remote server in python using scp or ssh?. I didn't get any error logs, the file just won't show in my current working directory. However every other command with os.system("ssh " + hostname + "command") or os.popen("ssh " + hostname + "command") does work. - command = e.g. ls When I try ssh hostname scp file user@local:directory in the commandline it works without entering a password. I tried to combine os.popen commands with getpass and pxssh module to establish a ssh connection to the remote server and use it to send commands directly (I only tested it for an easy command): import pxssh import getpass ssh = pxssh.pxssh() ssh.force_password = True hostname = raw_input("Hostname: ") user = raw_input("Username: ") password = getpass.getpass("Password: ") ssh.login(hostname, user, password) test = os.popen("hostname") print test But I'm not able to put commands through to the remote server (print test shows, that hostname = local and not the remote server), however I'm sure, the conection is established. I thought it would be easier to establish a connection than always use "ssh " + hostname in the bash commands. I also tried some of the workarounds in How do I copy a file to a remote server in python using scp or ssh?, but I must admit due to lack of expirience I didn't get them to work. Thanks a lot for helping me.

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  • How to visually reject user input in a table?

    - by FX
    In the programming of a table-based application module (i.e. the user mostly enters tabular data in an already laid-out table), how would you reject user input for a given cell? The scenario is: the user edits the cell, enters something (text, picture, ...) and you want them to notice when they finish editing (hitting enter, for example) that their entry is not valid for your given "format" (in the wider meaning: it can be that they entered a string instead of a number, that their entry is too long, too short, they include a picture while it's not acceptable, ...). I can see two different things happening: You can rather easily fit their entry into your format, and you do so, but you want them to notice it so they can change if your guess is not good enough (example: they entered "15.47" in a field that needs to be an integer, so your program makes it "15") You cannot guess what to do with their entry, and want to inform them that it's not valid. My question specifically is: what visual display can you offer to inform the user that his input is invalid? Is it preferable to refuse to leave the editing mode, or not? The two things I can imagine are: using colors (red background if invalid, yellow background for my case 1 above) when you reject an input, do something like Apple does for password entry of user accounts: you make the cell "shaking" (i.e. oscillating left and right) for one second, and keep the focus/editing in their so they don't loose what they've typed. Let's hear your suggestions. PS: This question is, at least in my thought process, somehow a continuation and a specialization of my previous question on getting users to read error messages. PPS: Made this community wiki, was that the right thing to do on this kind of question or not?

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  • How do I create rows with alternating colors for a UITableView on iPhone?

    - by Mat
    Hi all, i would to have alternate 2 colors of rows, like the first black, the second white, the third black, etc, etc... my approach is like a basic exercise of programming to calculate if a number is odd number or not: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; cell = ((MainCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]); if (cell==nil) { NSArray *topLevelObjects=[[NSBundle mainBundle] loadNibNamed:@"MainCell" owner:self options:nil]; for (id currentObject in topLevelObjects){ if ([currentObject isKindOfClass:[UITableViewCell class]]){ if ((indexPath.row % 2)==0) { [cell.contentView setBackgroundColor:[UIColor purpleColor]]; }else{ [cell.contentView setBackgroundColor:[UIColor whiteColor]]; } cell = (MainCell *) currentObject; break; } } }else { AsyncImageView* oldImage = (AsyncImageView*) [cell.contentView viewWithTag:999]; [oldImage removeFromSuperview]; }return cell; The problem is that when i do a rapid scroll, the background of cells become like the last 2 cell black, the first 2 cell white or something like this, but if i scroll slow works fine. I think the problem is the cache of reusableCell. Any ideas? TIA

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  • Socket isn't listed by netstat unless using certain ports

    - by illuzive
    I'm a computer science student with a few years of programming experience. Yesterday, while working on a project (Mac OS X, BSD sockets) at school, I encountered a strange problem. I was adding several modules to a very basic "server" (mostly a bunch of functions to set up and manage an UDP socket on a certain port). While doing this, I started the server from time to time in order to see that everything worked like it should. I've been using port 32000 during the development of the server. When I start the server and run netstat, the socket is listed as expected. > netstat -p UDP | grep 32000 udp46 0 0 *.32000 *.* However, when I run the server on other ports (random (10000 - 50000)), it's not listed by netstat. My thought was that I had somehow hard coded the port somewhere in the code, but that's not the case. The thing is - I can connect to the socket on any of the tested ports, and it reads data sent to it without any problem at all. It just doesn't get listed by netstat. What I wonder, is if anyone of you have any idea of why this happens? Note: Although this is a project at school, it's not homework. This is just something I want to understand for my own benefit.

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  • [OT a bit] Flex+JEE what is it good for?

    - by Zenzen
    Ok so sorry for being, I guess, a bit off topic but still I think this is the best place to ask. My new semester just started (don't worry I won't ask you to do my homework) and this time we have a rather cool subject about www programming in general where we have to do a web service, web abb - whatever as long as it's "web". Here's the problem though, my team and I want to do it with Flex and JEE but we don't have much experience about what are they actually used for. I mean we know you can do virtually anything with it, but we don't really want to lose time on doing something useless. My first idea was to do a "brainstorming" 3D room/service - a place where people could log in have a video conference, a whiteboard, a place to upload pictures everyone could see, some toolbars for google, youtube etc. plus some other features which would make real-time brainstorming easy when you can't get everyone in one place. But is Flex+JEE really suitable? I mean I'm 99% sure it's doable but is it really worth doing it in Flex+JEE or was the whole purpose of JEE completely different? @EDIT: well this was only one of our ideas obviously. I do know the basics of JSP, Servlets, JPA etc. of course but yeah the main goal of this project is to get some actual experience. The problem is we don't really know is it worth doing something like let's say a social network (something like extended facebook) for gamers (doesn't really matter if it already exists) in JEE or would it only look ridiculous (because PHP or whatever would be a far better choice)? Bottom line is that we are wondering are only large scale applications (for banks etc.) written in JEE or is it good for anything (even the smaller projects)?

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  • PHP: MySQL query duplicating update for no reason

    - by ThinkingInBits
    The code below is first the client code, then the class file. For some reason the 'deductTokens()' method is calling twice, thus charging an account double. I've been programming all night, so I may just need a second pair of eyes: if ($action == 'place_order') { if ($_REQUEST['unlimited'] == 200) { $license = 'extended'; } else { $license = 'standard'; } if ($photograph->isValidPhotographSize($photograph_id, $_REQUEST['size_radio'])) { $token_cost = $photograph->getTokenCost($_REQUEST['size_radio'], $_REQUEST['unlimited']); $order = new ImageOrder($_SESSION['user']['id'], $_REQUEST['size_radio'], $license, $token_cost); $order->saveOrder(); $order->deductTokens(); header('location: account.php'); } else { die("Please go back and select a valid photograph size"); } } ######CLASS CODE####### <?php include_once('database_classes.php'); class Order { protected $account_id; protected $cost; protected $license; public function __construct($account_id, $license, $cost) { $this->account_id = $account_id; $this->cost = $cost; $this->license = $license; } } class ImageOrder extends Order { protected $size; public function __construct($account_id, $size, $license, $cost) { $this->size = $size; parent::__construct($account_id, $license, $cost); } public function saveOrder() { //$db = Connect::connect(); //$account_id = $db->real_escape_string($this->account_id); //$size = $db->real_escape_string($this->size); //$license = $db->real_escape_string($this->license); //$cost = $db->real_escape_string($this->cost); } public function deductTokens() { $db = Connect::connect(); $account_id = $db->real_escape_string($this->account_id); $cost = $db->real_escape_string($this->cost); $query = "UPDATE accounts set tokens=tokens-$cost WHERE id=$account_id"; $result = $db->query($query); } } ?> When I die("$query"); directly after the query, it's printing the proper statement, and when I run that query within MySQL it works perfectly.

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  • How do I code and compile an Amiga application?

    - by nbolton
    I would like to program an application for the Amiga, just for fun! Please could someone post a step by step howto based on the following? Exactly what programming tools I should use, are there any already installed? Am I limited to plain text editors, or are there IDEs and debugging tools available? If no tools are already installed, how can this done? Are there free ones? I'd like to learn a traditional Amiga language, could you reccomend one? What should I use to compile the language you suggest? Please could you suggest tools I may use to debug the suggested language? Are there any libraries I should be aware of, such as GUI libraries? Some things to note... I'm running Workbench 3.1 from within the WinUAE emulator. From Workbench, I can access files from my Windows hard drive. I'd like to code and compile it from Workbench if possible. I'm running WinUAE in A1200 mode, not sure if that matters. There's an application already installed called MEmacs. I know C++ and C# very well, maybe there's a similar Amiga language. I'm aware that you can code with C and C++, but I want to learn a new language. Update: I have answered my own question, but please do contribute more answers as I intend on extending my answer. Thanks to all that have contributed so far, you've been very helpful!

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  • Quality of TFS 2008 merged code

    - by paologios
    Does the quality of code merged by TFS 2008 depend on the used programming language? I know merging in Java / Subversion, and merging a branch to its trunk usually does not create much conflicts. Now in my company, we use VB.NET. When I merge two files TFS does not always get code blocks right, e.g. does not find the right If..then / end if lines. To give you an example, I mean: File 2 is created as a branch of File 1. Both files were changed later, now I'm going to merge those files and am recieving conficts: The marked end-if lines (1) are detected as corresponding, meaning the added event handler Button1_Click is being deleted. Now I wonder if this behavior is by language (C# vs. VB.NET) or are other source control solutions just better than TFS? (And I really liked TFS up to now :) ) File 1: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Not Page.IsPostBack Then Label1.Text = "Hello" Label2.Text = "World" End If End Sub Protected Sub Button2_Click(ByVal sender, ByVal e as System.EventArgs) Handles Button2.Click // .... If Page.IsValid Then Label3.Text = "Hello Button 2" End If // .... End Sub File 2 (Branch of File 1): Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Not Page.IsPostBack Then fillTableFromDatabase() End If // (1) End Sub Protected Sub Button1_Click(ByVal sender, ByVal e as System.EventArgs) Handles Button1.Click // do something here End Sub Protected Sub Button2_Click(ByVal sender, ByVal e as System.EventArgs) Handles Button2.Click // .... If Page.IsValid Then End If // (1) // .... End Sub

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  • Connect.registerUsers - Need helping creating array for accounts param

    - by mw_javaguy
    I keep getting the following error when I try to invoke the Facebook REST API Call: Connect.registerUsers Error Code: 100 - param accounts must be an array JSON based response (from Facebook): {"error_code":100,"error_msg":"param accounts must be an array.","request_args": [{"key":"accounts","value":"{email_hash:5232156322_55ddgvc3db5ddcf218049dd564da2x06}"}, {"key":"api_key","value":"23b2c4c6a23445fbffssf8aab96a5e5"}, {"key":"format","value":"JSON"},{"key":"method","value":"Connect.registerUsers"},{"key":"sig","value":"3sd54153a31382fa6e72eecf3c57d7c9"},{"key":"v","value":"1.0"}],"message":"Unknown exception","code":0} I set up the Java code to invoke the REST end point using HttpClient like this: String API_KEY = "23b2c4c6a23445fbffssf8aab96a5e5"; String toConnectRegisterUsersSignature = "accounts=" + "{email_hash:" + emailHash + "}" + "api_key=" + API_KEY + "format=JSON" + "method=Connect.registerUsers" + "v=1.0" + "0c786155bd3cxe8228d924542da5gf2"; String connectRegisterUsersSignature = SimpleMd5.MD5(toConnectRegisterUsersSignature); NameValuePair[] connectRegisterUsersParameters = { new NameValuePair("accounts", "{email_hash:" + emailHash + "}"), new NameValuePair("api_key", API_KEY), new NameValuePair("format", "JSON"), new NameValuePair("method", "Connect.registerUsers"), new NameValuePair("sig", connectRegisterUsersSignature), new NameValuePair("v", "1.0") }; Tried the following combinations and I still get the same error! Signature: "accounts=" + "[email_hash=" + emailHash + "]" new NameValuePair("accounts", "[email_hash=" + emailHash + "]") Signature: "accounts=" + "email_hash[" + emailHash + "]" new NameValuePair("accounts", "email_hash[" + emailHash + "]") Signature: "accounts=" + "email_hash(" + emailHash + ")" new NameValuePair("accounts", "email_hash(" + emailHash + ")") Signature: "accounts=" + "[email_hash=" + emailHash + "]" new NameValuePair("accounts", "[email_hash=" + emailHash + "]") Signature: "accounts=" + "email_hash=" + emailHash new NameValuePair("accounts", "email_hash=" + emailHash) Signature: "accounts=" + "[{email_hash:" + emailHash + "}]" new NameValuePair("accounts", "[{email_hash:" + emailHash + "}]"), Does anyone know how to construct this array that the response is requesting? Happy programming and thank you for taking the time to read this.

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  • Static Vs Non-Static Method Performance C#

    - by dotnetguts
    Hello All, I have few global methods declared in public class in my asp.net web application. I have habbit of declaring all global methods in public class in following format public static string MethodName(parameters) { } I want to know how it would impact on performance point of view? 1) Which one is Better? Static Method or Non-Static Method? 2) Reason why it is better? Following link shows Non-Static methods are good because, static methods are using locks to be Thread-safe. The always do internally a Monitor.Enter() and Monitor.exit() to ensure Thread-safety. http://bytes.com/topic/c-sharp/answers/231701-static-vs-non-static-function-performance And Following link shows Static Methods are good static methods are normally faster to invoke on the call stack than instance methods. There are several reasons for this in the C# programming language. Instance methods actually use the 'this' instance pointer as the first parameter, so an instance method will always have that overhead. Instance methods are also implemented with the callvirt instruction in the intermediate language, which imposes a slight overhead. Please note that changing your methods to static methods is unlikely to help much on ambitious performance goals, but it can help a tiny bit and possibly lead to further reductions. http://dotnetperls.com/static-method I am little confuse which one to use? Thanks

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  • How do I add code automatically to a derived function in C++

    - by Ian
    I have code that's meant to manage operations on both a networked client and a server, since there is significant overlap between the two. However, there are a few functions here and there that are meant to be exclusively called by the client or server, and accidentally calling a client function on the server (or vice versa) is a significant source of bugs. To reduce these sorts of programming errors, I'm trying to tag functions so that they'll raise a ruckus if they're misused. My current solution is a simple macro at the start of each function that calls an assert if the client or server accesses members they shouldn't. However, this runs into problems when there are multiple derived instances of classes, in that I have to tag the implementation as client or server side in EVERY child class. What I'd like to be able to do is put a tag in the virtual member's signature in the base class, so that I only have to tag it once and not run into errors by forgetting to do it repeatedly. I've considered putting a check in a base class implementation and then referring to it with something like base::functionName, but that runs into the same issue as far as needing to manually add the function call to every implementation. Ideally, I'd be able to have parent versions of the function called automatically like default constructors do. Does anybody know how to achieve something like this in C++? Is there an alternate approach I should be considering? Thanks!

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  • eclipse - starting with android sdk

    - by dontHaveName
    I want start programming for android.. What I have: -Windows 7 -Eclipse Classic 4.2 -Downloaded all there required files - http://developer.android.com/sdk/installing/adding-packages.html -ADT Plugin I want install new ADT plugin.. at first I tried to download it from http://dl-ssl.google.com/android/eclipse, I add it, but if i selected it there is only "pending.." and nothing has load..(maybe internet connection?I have selected Native connection in preferences after pending it wrotes: Unable to connect to repository http://dl-ssl.google.com/android/eclipse/content.xml org.eclipse.equinox.p2.core.ProvidesException ) Thats why I download ADT plugin. So if I select downloaded ADT plugin - content of it load - developer tools and ndk plugin so I select all and click next. It loads and writes this: "Cannot complete the install because one or more required items could not be found. Software being installed: Android Development Tools 20.0.3.v201208082019-427395 (com.android.ide.eclipse.adt.feature.group 20.0.3.v201208082019-427395) Missing requirement: Android Development Tools 20.0.3.v201208082019-427395 (com.android.ide.eclipse.adt.feature.group 20.0.3.v201208082019-427395) requires 'org.eclipse.wst.sse.core 0.0.0' but it could not be found" requires 'org.eclipse.wst.sse.core 0.0.0 this problem is shown here: http://developer.android.com/resources/faq/troubleshooting.html#installeclipsecomponents but there is solution only for version 3.3 and 3.4 (I have 4.2) anyway but I tried it- I look for updates but nothing were found I really dont know where could be problem.. Thanks for any answer. (sorry for my english) I will send 1€ to somebody who can solve my problem ;) (I think all problems all for internet connection but I cant set it..)

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  • Difference between float and double

    - by VaioIsBorn
    I know, i've read about the difference between double precision and single precision etc. But they should give the same results on most cases right ? I was solving a problem on a programming contest and there were calculations with floating point numbers that were not really big so i decided to use float instead of double, and i checked it - i was getting the correct results. But when i send the solution, it said only 1 of 10 tests was correct. I checked again and again, until i found that using float is not the same using double. I put double for the calculations and double for the output, and the program gave the SAME results, but this time it passed all the 10 tests correctly. I repeat, the output was the SAME, the results were the SAME, but putting float didn't work - only double. The values were not so big too, and the program gave the same results on the same tests both with float and double, but the online judge accepted only the double-provided solution. Why ? What is the difference ?

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  • Why are (almost) all the on-line games written in ActionScript (Flash) not Java?

    - by MasterPeter
    I absolutely love good defender games (e.g. Gemcraft, Protector: reclaiming the throne) as they can be intellectually quite challenging; it's like playing chess but a little less thinking a bit more action. Sadly, there are not that many good ones out there and I thought I would create one myself and share it with the rest of the world by making it available on-line. I have never worked with ActionScript but when it comes to on-line games, this is the main choice. I have tried to find a decent 2D game in the form of a Java applet but to no avail. Why is this so? I could write the game, most comfortably, in Delphi for Win32 but then people would need to download the executable, which could deter some form downloading it, and also it would only work on Windows. I am also familiar with Java, having worked with Java for the last four years or so. Although I don't have much experience with games programming. Should I note be deterred by the fact that all online games are written for in Flash and create my defender game as a Java applet, or should I consider learning ActionScript and games development for the ActionScript Virtual Machine (AS3 looks very much like Java... but still, it's an entirely new technology to me and I might never use it professionally.) Could you, please, just answer the the question in the title? Why Flash, not Java applets? Is it only 'politics'?

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  • Recursive powerof-function, see if you can solve it

    - by Jonas B
    First of all, this is not schoolwork - just my curiousity as I for some reason can't get my head around it and solve it. I come up with these stupid things all the time and it annoys the hell out of me when I cant solve them. Code example is in C# but solution doesn't have to be in any particular programming-language. long powerofnum(short num, long powerof) { return powerofnum2(num, powerof, powerof); } long powerofnum2(short num, long powerof, long holder) { if (num == 1) return powerof; else { return powerof = powerofnum2(num - 1, holder * powerof, holder); } } As you can see I have two methods. I call for powerofnum(value, powerofvalue) which then calls the next method with the powerofvalue also in a third parameter as a placeholder so it remembers the original powerof value through the recursion. What I want to accomplish is to do this with only one method. I know I could just declare a variable in the first method with the powerof value to remember it and then iterate from 0 to value of num. But as this is a theoretical question I want it done recursively. I could also in the first method just take a third parameter called whatever to store the value just like I do in the second method that is called by the first, but that looks really stupid. Why should you have to write what seems like the same parameter twice? Rules explained in short: no iteration scope-specific variables only only one method Anyhow, I'd appreciate a clean solution. Good luck :)

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  • How to catch an incomming text message

    - by Espen
    Hi! I want to be able to control incoming text messages. My application is still on a "proof of concept" version and I'm trying to learn Android programming as I go. First my application need to catch incomming text messages. And if the message is from a known number then deal with it. If not, then send the message as nothing has happened to the default text message application. I have no doubt it can be done, but I still have some concern and I see some pitfalls at how things are done on Android. So getting the incomming text message could be fairly easy - except when there are other messaging applications installed and maybe the user wants to have normal text messages to pop up on one of them - and it will, after my application has had a look at it first. How to be sure my application get first pick of incomming text messages? And after that I need to send most text messages through to any other text message application the user has chosen so the user can actually read the message my application didn't need. Since Android uses intents that are relative at best, I don't see how I can enforce my application to get a peek at all incomming text messages, and then stop it or send it through to the default text messaging application...

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  • How to handle 'this' pointer in constructor?

    - by Kyle
    I have objects which create other child objects within their constructors, passing 'this' so the child can save a pointer back to its parent. I use boost::shared_ptr extensively in my programming as a safer alternative to std::auto_ptr or raw pointers. So the child would have code such as shared_ptr<Parent>, and boost provides the shared_from_this() method which the parent can give to the child. My problem is that shared_from_this() cannot be used in a constructor, which isn't really a crime because 'this' should not be used in a constructor anyways unless you know what you're doing and don't mind the limitations. Google's C++ Style Guide states that constructors should merely set member variables to their initial values. Any complex initialization should go in an explicit Init() method. This solves the 'this-in-constructor' problem as well as a few others as well. What bothers me is that people using your code now must remember to call Init() every time they construct one of your objects. The only way I can think of to enforce this is by having an assertion that Init() has already been called at the top of every member function, but this is tedious to write and cumbersome to execute. Are there any idioms out there that solve this problem at any step along the way?

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  • how to share a variable between two threads

    - by prmatta
    I just inherited some code, two threads within this code need to perform a system task. One thread should do the system task before the other thread. They should not be performing the system task together. The two threads do not have references to each other. Now, I know I can use some sort of a semaphore to achieve this. But my question is what is the right way to get both threads to access this semaphore. I could create a static variable/method a new class : public class SharedSemaphore { private static Semaphore s = new Semaphore (1, true); public static void performSystemTask () { s.acquire(); } public static void donePerformingSystemTask() { s.release(); } } This would work (right?) but this doesn't seem like the right thing to do. Because, the threads now have access to a semaphore, without ever having a reference to it. This sort of thing doesn't seem like a good programming practice. Am I wrong?

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  • Storing header and data sections in a CSV file

    - by morpheous
    This should be relatively easy to do, but after several hours straight programming my mind seems a bit frazzled and could do with some help. I have a C++ class which I am currently using to store read/write data to file. I was initially using binary data, but have decided to store the data as CSV in order to let programs written in other languages be able to load the data. The C++ class looks a bit like this: class BinaryData { public: BinaryData(); void serialize(std::ostream& output) const; void deserialize(std::istream& input); private: Header m_hdr; std::vector<Row> m_rows; }; I am simply rewriting the serialize/deserialize methods to write to a CSV file. I am not sure on the "best" way to store a header section and a "data" section in a "flat" CSV file though - any suggestions on the most sensible way to do this?

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  • multiple clients - one server connection with sockets tcp/ip c# .net

    - by jagse
    Hello guys, I need to develop a client server system where I can have multiple clients communicating with one server at the same time. I want to communicate xml serialized objects and also need to send and receive other commands to invoke methods. Now, I am just starting with socket programming in C# and .Net and found that the asynchronous I/O is the way to go so that the methods dont block the execution of code. Also there are many examples of how to make a simple client server system. So I have a basic understanding of how that works. Anyway, what still is not clear to me is how I can set up a server which can manage connections to multiple clients? Can I just create a new socket per connection and then store those in some kind of list? Do I need some kind of multiplexing to achieve this? Do I have to listen at multiple ports? What`s the best way here? And the other thing is if I need to develop my own protocol to differentiate between what I am actually sending over the network -- xml serialized object or a command which might be just a string encoded in ascII or something. Or would I develop my own protocol just to send these commands? Any kind of help is apreciated! If someone knows a good book which covers this sort of stuff, let me know. Cheers I forgot to mention that some of my clients which are supposed to communicate with my server will be pda and I therefore use the compact framework... So this might bring in some restrictions...

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  • Strange problem with simple multithreading program in Java

    - by Elizabeth
    Hello, I am just starting play with multithreading programming. I would like to my program show alternately character '-' and '+' but it doesn't. My task is to use synchronized keyword. As far I have: class FunnyStringGenerator{ private char c; public FunnyStringGenerator(){ c = '-'; } public synchronized char next(){ if(c == '-'){ c = '+'; } else{ c = '-'; } return c; } } class ThreadToGenerateStr implements Runnable{ FunnyStringGenerator gen; public ThreadToGenerateStr(FunnyStringGenerator fsg){ gen = fsg; } @Override public void run() { for(int i = 0; i < 10; i++){ System.out.print(gen.next()); } } } public class Main{ public static void main(String[] args) throws IOException { FunnyStringGenerator FSG = new FunnyStringGenerator(); ExecutorService exec = Executors.newCachedThreadPool(); for(int i = 0; i < 20; i++){ exec.execute(new ThreadToGenerateStr(FSG)); } } } EDIT: I also testing Thread.sleep in run method instead for loop.

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  • How do I create a simple Windows form to access a SQL Server database?

    - by NoCatharsis
    I believe this is a very novice question, and if I'm using the wrong forum to ask, please advise. I have a basic understanding of databasing with MS SQL Server, and programming with C++ and C#. I'm trying to teach myself more by setting up my own database with MS SQL Server Express 2008 R2 and accessing it via Windows forms created in C# Express 2010. At this point, I just want to keep it to free or Express dev tools (not necessarily Microsoft though). Anyway, I created a database using the instructions provided here and I set the data types appropriately for each column (no errors in setup at least). Now I'm designing the GUI in C# Express but I've kind of hit a wall as far as the database connection. Is there a simple way to access the database I created locally using C# Express? Can anyone suggest a guide that has all this spelled out already? I am a self-learner so I look forward to teaching myself how to use these applications, but any pointers to start me off in the right direction would be greatly appreciated.

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  • Keyboard shortcut to Un/Comment out code in Mathematica 7?

    - by dbjohn
    A keyboard shortcut to comment/uncomment out a piece of code is common in other programming IDE's for languages like Java, .Net. I find it a very useful technique when experimenting through trial and error to temporarily comment out and uncomment lines, words and parts of the code to find out what is and isn't working. I cannot find any such keyboard shortcut on the Mathematica front end in version 7. I know that it is possible to comment out code by selecting the code, right mouse click and select Un/Comment from the menu that appears but this is too slow while coding. I tried to access this using the menu key Menu on the keyboard but Mathematica frontend doesn't respond to or recognise this key unlike other applications, this could have allowed a key combination for commenting. Can someone else verify that this isn't unique to my machine and that the key isn't recognised by mathematica. I looked at this question and looked in the KeyEventTranslations.tr file but I don't think there is any way to create a shortcut to do this(?). Should I just live with it? Any other suggestions? (I have seen there is an Emacs version of mathematica, I have never tried Emacs or this Mma version and imagine that it would have this ability but would prefer not to go to the trouble and uncertainty of installing it. Also I would guess that the Wolfram Workbench could do this, but that may not be worth the investment just for this.)

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  • efficient android rendering

    - by llll
    I've read quite a few tutorials on game programming on android, and all of them provide basically the same solution as to drawing the game, that is having a dedicated thread spinning like this: public void run() { while(true) { if(!surfaceHolder.getSurface().isValid()) continue; Canvas canvas = surfaceHolder.lockCanvas(); drawGame(canvas); /* do actual drawing here */ surfaceHolder.unlockCanvasAndPost(canvas); } } now I'm wondering, isn't this wasteful? Suppose I've a game with very simple graphics, so that the actual time in drawGame is little; then I'm going to draw the same things on and on, stealing cpu from the other threads; a possibility could be skipping the drawing and sleeping a bit if the game state hasn't changed, which I could check by having the state update thread mantaining a suitable status flag. But maybe there are other options. For example, couldn'it be possible to synchronize with rendering, so that I don't post updates too often? Or am I missing something and that is precisely what lockCanvas does, that is it blocks and burns no cpu until proper time? Thanks in advance L.

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  • With C# 3.0, how to write Interface based code with generic collection?

    - by Deecay
    I want to write code that is decouple and clean, and I know that by programming to an interface instead of the implementation, my code will be more flexible and extensible. So, instead of writing methods like: bool IsProductAvailable(ProductTypeA product); I write methods like: bool IsProductAvailable(IProduct product); As long as my products implement IProduct: class ProductTypeA : IProduct I should be OK. All is well until I start using generic collections. Since C# 3.0 doesn't support covariant and contravariant, even though both ProuctTypeA and ProductTypeB implements IProduct, you cannot put List in List. This is pretty troublesome because a lot of times I want to write something like: bool AreProductsAvailable(List<IProduct> products); So that I can check product avaialbility by writing: List<ProductA> productsArrived = GetDataFromDataabase(); bool result = AreProductsAvailable(productsArrived); And I want to write just one AreProductsAvailable() method that works with all IProduct collections. I know that C# 4.0 is going to support covariant and contravariant, but I also realize that there other libraries that seemed to have the problem solved. For instance, I was trying out ILOG Gantt the gantt chart control, and found that they have a lot of collection intefaces that looks like this: IActivityCollection ILinkCollection So it seems like their approach is wrapping the generic collection with an interface. So instead of "bool AreProductsAvailable(List products);", I can do: bool AreProductsAvailable(IProductCollection products); And then write some code so that IProductCollection takes whatever generic collection of IProduct, be it List or List. However, I don't know how to write an IProductCollection interface that does that "magic". :-< (ashame) .... Could someone shed me some light? This has been bugging me for so long, and I so wanted to do the "right thing". Well, thanks!

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