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• Stupid newbie c++ two-dimensional array problem.

  - by paulson scott

  I've no idea if this is too newbie or generic for stackoverlflow. Apologies if that's the case, I don't intend to waste time. I've just started working through C++ Primer Plus and I've hit a little stump. This is probably super laughable but: for (int year = 0; year < YEARS; year++) { cout << "Year " << year + 1 << ":"; for (int month = 0; month < MONTHS; month++) { absoluteTotal = (yearlyTotal[year][year] += sales[year][month]); } cout << yearlyTotal[year][year] << endl; } cout << "The total number of books sold over a period of " << YEARS << " years is: " << absoluteTotal << endl; I wish to display the total of all 3 years. The rest of the code works fine: input is fine, individual yearly output is fine but I just can't get 3 years added together for one final total. I did have the total working at one point but I didn't have the individual totals working. I messed with it and reversed the situation. I've been messing with it for God knows how long. Any idea guys? Sorry if this isn't the place!

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• Symfony: joining two forms in the same page

  - by user248959

  Hi, i'm trying to join in the same action the login and the register forms. This is what i'm trying: modules/miembros/actions.class.php public function executeAux(sfWebRequest $request) { // I execute this action } modules/miembros/templates/auxSuccess.php <?php include_component('sfGuardRegister', 'register'); ?> <?php include_component('sfGuardAuth', 'signin'); ?> modules/miembros/components.class.php public function executeSignin($request) { if ( $request->isMethod( 'post' ) && ($request- >getParameter('submit')=='signin') ){ $this->form->bind( $request->getParameter( 'login' ) ); if ( $this->form->isValid() ){ $this->getController()->getActionStack()->getLastEntry()->getActionInstance()->redirect( '@home' ); } } } modules/miembros/templates/_signin.php <form action="<?php echo url_for('miembros/aux?submit=signin') ?>" method="post"> <?php echo $form['email_address']->renderLabel() ?> <?php echo $form['email_address'] ?> ... It's working ok, but i would to know if you have other alternatives. Regards Javi

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• Two entities with @ManyToOne should join the same table

  - by Ivan Yatskevich

  I have the following entities Student @Entity public class Student implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Teacher @Entity public class Teacher implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Task @Entity public class Task implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "student_id") }) private Student author; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "teacher_id") }) private Teacher curator; //getters and setters } Consider that author and curator are already stored in DB and both are in the attached state. I'm trying to persist my Task: Task task = new Task(); task.setAuthor(author); task.setCurator(curator); entityManager.persist(task); Hibernate executes the following SQL: insert into student_task (teacher_id, id) values (?, ?) which, of course, leads to null value in column "student_id" violates not-null constraint Can anyone explain this issue and possible ways to resolve it?

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• how to design two inputs in or/And logic for email form with validation

  - by Raj Nimbalkar

  my purpose is user enter only email or mobile number.i have the partial success in that.code notify user in OR logic but....IF user entered the incorrect mobile & email @same time then user must be notified for dat. var emailReg = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/; var emailaddressVal = $("#UserEmail").val(); ////email & mobile input cheak if(emailaddressVal == '' && $("#mobile").val() == '') { $("#UserEmail").after('<p><span class="error">Please enter your email address.</span></p>') $("#mobile").after('<p><span class="error">Please enter your Mobile number.</span></p>') hasError = true; } //////validating currect email else if(!emailReg.test(emailaddressVal)) { $("#UserEmail").after('<p><span class="error">Enter a valid email address.</span></p>') hasError = true; } //////Mobile number else if( $("#mobile").val()) { $("#mobile").after('<p><span class="error">Enter currect Mobile number.</span></p>') hasError = true; }

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• data transmission between two sites

  - by SaMSa

  I'm use Asp.Net Mvc 4 www.hostname.com to my site from my report.hostname2.com send and receive data to move directly to that address by the string bi codebehind. querysstring not, because sending a very long string I mean rapor.coskunoglu.net/Pdf address to send string data to move directly to that address PDF of the screen to make it appear so. How can I do this? Thank you, take it easy. I'm sorry, my english is not good. EDIT: I want to use POST. sb - my StringBuilder. byte[] bytt = Encoding.UTF8.GetBytes(sb.ToString()); WebRequest wr = WebRequest.Create("http://report.hostname2.com/Pdf"); wr.ContentType = "application/x-www-form-urlencoded"; wr.ContentLength = bytt.Length; wr.Method = "POST"; Stream st = wr.GetRequestStream(); st.Write(bytt, 0, bytt.Length); st.Close(); After you send the POST I want to go to report.hostname2.com. Did you see this my job?

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• .htaccess, two consecutive rewrites?

  - by Matthew Haworth

  I need to take a url, "/ServiceSearch/r.php?n=blahblah", and have it go to "/search/blahblah/" so that it appears in the browser as "/search/blahblah", but I actually want it to REALLY be going to "r.php?n=ServiceSearch&n=blahblah".. So I was thinking I'll need to rewrite the first URL to "/ServiceSearch/r.php?n=blahblah" and then the second url, "/search/blahblah/", to the third, "r.php?n=ServiceSearch&n=blahblah". Well, I know this is wrong, but it's my best guess. I'm really struggling with it.

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• Are these two functions the same?

  - by Ranhiru

  There is a function in the AES algorithm, to multiply a byte by 2 in Galois Field. This is the function given in a website private static byte gfmultby02(byte b) { if (b < 0x80) return (byte)(int)(b <<1); else return (byte)( (int)(b << 1) ^ (int)(0x1b) ); } This is the function i wrote. private static byte MulGF2(byte x) { if (x < 0x80) return (byte)(x << 1); else { return (byte)((x << 1) ^ 0x1b); } } What i need to know is, given any byte whether this will perform in the same manner. Actually I am worried about the extra conversion of to int and then again to byte. So far I have tested and it looks fine. Does the extra cast to int and then to byte make a difference?

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• Two Phase Commit with MongoDB

  - by mattcodes

  Heres what Im thinking. Do you see any issues with this workaround to emulate 2 phase commit when using something like MongoDB where each operation is atomic and there is no support for transactions outside of that? transaction_scope: read message from servicebus - UpdateCustomerAddress get customer aggregate from docdb, replay events where commited =1 call customer.updateAddress validates creates customer address updated event apply event event store as uncommitted events do optimistic concurrency update against docdb pushing uncommitted events (single op to ensure consistency) publish event to service bus update docdb set events just published to commited = 1 (again one 1 op - at least in mongodb) transaction_complete

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• Python: two loops at once

  - by Stephan Meijer

  I've got a problem: I am new to Python and I want to do multiple loops. I want to run a WebSocket client (Autobahn) and I want to run a loop which shows the filed which are edited in a specific folder (pyinotify or else Watchdog). Both are running forever, Great. Is there a way to run them at once and send a message via the WebSocket connection while I'm running the FileSystemWatcher, like with callbacks, multithreading, multiprocessing or just separate files? factory = WebSocketClientFactory("ws://localhost:8888/ws", debug=False) factory.protocol = self.webSocket connectWS(factory) reactor.run() If we run this, it will have success. But if we run this: factory = WebSocketClientFactory("ws://localhost:8888/ws", debug=False) factory.protocol = self.webSocket connectWS(factory) reactor.run() # Websocket client running now,running the filewatcher wm = pyinotify.WatchManager() mask = pyinotify.IN_DELETE | pyinotify.IN_CREATE # watched events class EventHandler(pyinotify.ProcessEvent): def process_IN_CREATE(self, event): print "Creating:", event.pathname def process_IN_DELETE(self, event): print "Removing:", event.pathname handler = EventHandler() notifier = pyinotify.Notifier(wm, handler) wdd = wm.add_watch('/tmp', mask, rec=True) notifier.loop() This will create 2 loops, but since we already have a loop, the code after 'reactor.run()' will not run at all.. For your information: this project is going to be a sync client. Thanks a lot!

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• How to compare two "not integer" values in shell script

  - by Reem

  I had to do a division in shell script and the best way was: result1=`echo "scale=3; ($var1 / $total) * 100"| bc -l` result2=`echo "scale=3; ($var2 / $total) * 100"| bc -l` but I want to compare the values of $result1 and $result2 Using if test $result1 -lt $result2 or if [ $result1 -gt $result2 ] didn't work :( Any idea how to do that?

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• How to apply Containstable 4 two join table?

  - by jaykanth

  product table pid modelnumber 1 a 2 b 3 c ProductTransation pid name description... 1 ball ball 2 bat cricket bat i create fullText for Modelnumber in product table. " for name & Description in productTrasaction table. Now i want to join this table if i search through modelnumber or name result should be pid name modelnumber 1 ball a

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• Python:Comparing Two Dictionaries

  - by saun jean

  The first Dict is fixed.This Dict will remain as it is List of Countries with there Short Names. firstDict={'ERITREA': 'ER', 'LAOS': 'LA', 'PORTUGAL': 'PT', "D'IVOIRE": 'CI', 'MONTENEGRO': 'ME', 'NEW CALEDONIA': 'NC', 'SVALBARD AND JAN MAYEN': 'SJ', 'BAHAMAS': 'BS', 'TOGO': 'TG', 'CROATIA': 'HR', 'LUXEMBOURG': 'LU', 'GHANA': 'GH'} However This Tuple result has multiple Dict inside it.This is the format in which MySQLdb returns result: result =({'count': 1L, 'country': 'Eritrea'}, {'count': 1L, 'country': 'Togo'}, {'count': 1L, 'country': 'Sierra Leone'}, {'count': 3L, 'country': 'Bahamas'}, {'count': 1L, 'country': 'Ghana'}) Now i want to compare these both results With COUNTRY Names and If 'Country' in Result is present in firstDict then put the value.else put the 0 The result desired is: mainRes={'ER':1,'TG':1,'BS':3,'GH':0,'LU':0}

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• php with two class

  - by lolalola

  Hi Guys, my sample is good or not? I have a good connection to the database, or too should be in the class? Thanks <?php mysql_connect('localhost','root','admin'); mysql_select_db('test'); class UserDisplay { function getDisplayName() { $sql = 'select first_name, last_name, display_name from users where user_id = "3"'; $results = mysql_query($sql); $row = mysql_fetch_array($results); $this->user_id = $user_id; return $this->user_id; } } class UserInsert function InsertName($name) { mysql_query("INSERT INTO Persons (first_name)VALUES ('".$name."')"); } } $userD = new UserDisplay(); echo "User known as: " . $userD->getDisplayName() . "\n"; $userI = new UserInsert(); $userI->InsertName("Peter"); ?>

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• Comparing two images from the clipboard class

  - by VeXe

  In a C# winform app. I'm writing a Clipboard log manager that logs test to a log file, (everytime a Ctrl+c/x is pressed the copied/cut text gets appended to the file) I also did the same for images, that is, if you press "prtScreen", the screen shot you took will also go to a folder. I do that by using a timer, inside I have something which 'looks' like this: if (Clipboard.ContainsImage()) { if (IsClipboardUpdated()) { LogData(); UpdateLastClipboardData(); } } This is how the rest of the methods look like: public void UpdateLastClipboardData() { // ... other updates LastClipboardImage = Clipboard.GetImage(); } // This is how I determine if there's a new image in the clipboard... public bool IsClipboardUpdated() { return (LastClipboardImage != Clipboard.GetImage()); } public void LogData() { Clipboard.GetImage().Save(ImagesLogFolder + "\\Image" + now_hours + "_" + now_mins + "_" + now_secs + ".jpg"); } The problem is: inside the update method, "LastClipboardImage != Clipboard.GetImage()" is always returning true! I even did the following inside the update method: Image img1 = Clipboard.GetImage(); Image img2 = Clipboard.GetImage(); Image img3 = img2; bool b1 = img1 == img2; // this returned false. WHY?? bool b2 = img3 == img2; // this returned true. Makes sense. Please help, the comparison isn't working... why?

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• How to mix two arrays in Java?

  - by roddik

  Hello. I have some String[] arrays, for example: ['a1', 'a2'] ['b1', 'b2', 'b3', 'b4'] ['c1'] How can I mix them, so that I get ['a1', 'b1', 'c1', 'a2', 'b2', 'b3', 'b4'] (0 element of a, then b, c, 1 element of a, b, c and so on)? Thanks

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• Help Forming An SQL Query That Selects The Max Difference Of Two Fields

  - by Frank

  I'm trying to select a record with the most effective votes. Each record has an id, the number of upvotes (int) and the number of downvotes (int) in a MySQL database. I know basic update, select, insert queries but I'm unsure of how to form a query that looks something like: SELECT * FROM topics WHERE MAX(topic.upvotes - topic.downvotes). Please excuse my made up SQL. The tutorials on SQL I find on the internet cover very basic stuff. Does anyone recommend a good book on this subject?

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• PHP: Join two separate mysql queries into the same json data object

  - by Dan

  I'm trying to mesh the below mysql query results into a single json object, but not quite sure how to do it properly. //return data $sql_result = mysql_query($sql,$connection) or die ("Fail."); $arr = array(); while($obj = mysql_fetch_object($sql_result)) { $arr[] = $obj; } echo json_encode($arr); //return json //plus the selected options $sql_result2 = mysql_query($sql2,$connection) or die ("Fail."); $arr2 = array(); while($obj2 = mysql_fetch_object($sql_result2)) { $arr2[] = $obj2; } echo json_encode($arr2); //return json Here's the current result: [{"po_number":"test","start_date":"1261116000","end_date":"1262239200","description":"test","taa_required":"0","account_overdue":"1","jobs_id":null,"job_number":null,"companies_id":"4","companies_name":"Primacore Inc."}][{"types_id":"37"},{"types_id":"4"}] Notice how the last section [{"types_id":"37"},{"types_id":"4"}] is placed into a separate chunk under root. I'm wanting it to be nested inside the first branch under a name like, "types". I think my question has more to do with Php array manipulation, but I'm not the best with that. Thank you for any guidance.

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• Many to Many delete in NHibernate two parents with common association

  - by Joshua Grippo

  I have 3 top level entities in my app: Circuit, Issue, Document Circuits can contain Documents and Issues can contain Documents. When I delete a Circuit, I want it to delete the documents associated with it, unless it is used by something else. I would like this same behavior with Issues. I have it working when the only association is in the same table in the db, but if it is in another table, then it fails due to foreign key constraints. ex 1(This will cascade properly, because there is only a foreign constraint from Circuit to Document) Document1 exists. Circuit1 exists and contains a reference to Document1. If I delete Circuit1 then it deletes Document1 with it. ex 2(This will cascade properly, because there is only a foreign constraint from Circuit to Document.) Document1 exists. Circuit1 exists and contains a reference to Document1. Circuit2 exists and contains a reference to Document1. If I delete Circuit1 then it is deleted, but Document1 is not deleted because Circuit2 exists. If I then delete Circuit2, then Document1 is deleted. ex 3(This will throw an error, because when it deletes the Circuit it sees that there are no other circuits that reference the document so it tries to delete the document. However it should not, because there is an Issue that has a foreign constraint to the document.) Document 1 exists. Circuit1 exists and contains a reference to Document1. Issue1 exists and contains a reference to Document1. If I delete Circuit1, then it fails, because it tries to delete Document1, but Issues1 still has a reference. DB: This think won't let upload an image, so here is the ERD to the DB: http://lh3.ggpht.com/_jZWhe7NXay8/TROJhOd7qlI/AAAAAAAAAGU/rkni3oEANvc/CircuitIssues.gif Model: public class Circuit { public virtual int CircuitID { get; set; } public virtual string CJON { get; set; } public virtual IList<Document> Documents { get; set; } } public class Issue { public virtual int IssueID { get; set; } public virtual string Summary { get; set; } public virtual IList<Model.Document> Documents { get; set; } } public class Document { public virtual int DocumentID { get; set; } public virtual string Data { get; set; } } Mapping Files: <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Model" assembly="Model"> <class name="Circuit" table="Circuit"> <id name="CircuitID"> <column name="CircuitID" not-null="true"/> <generator class="identity" /> </id> <property name="CJON" column="CJON" type="string" not-null="true"/> <bag name="Documents" table="CircuitDocument" cascade="save-update,delete-orphan"> <key column="CircuitID"/> <many-to-many class="Document"> <column name="DocumentID" not-null="true"/> </many-to-many> </bag> </class> </hibernate-mapping> <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Model" assembly="Model"> <class name="Issue" table="Issue"> <id name="IssueID"> <column name="IssueID" not-null="true"/> <generator class="identity" /> </id> <property name="Summary" column="Summary" type="string" not-null="true"/> <bag name="Documents" table="IssueDocument" cascade="save-update,delete-orphan"> <key column="IssueID"/> <many-to-many class="Document"> <column name="DocumentID" not-null="true"/> </many-to-many> </bag> </class> </hibernate-mapping> <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Model" assembly="Model"> <class name="Document" table="Document"> <id name="DocumentID"> <column name="DocumentID" not-null="true"/> <generator class="identity" /> </id> <property name="Data" column="Data" type="string" not-null="true"/> </class> </hibernate-mapping> Code: using (ISession session = sessionFactory.OpenSession()) { var doc = new Model.Document() { Data = "Doc" }; var circuit = new Model.Circuit() { CJON = "circ" }; circuit.Documents = new List<Model.Document>(new Model.Document[] { doc }); var issue = new Model.Issue() { Summary = "iss" }; issue.Documents = new List<Model.Document>(new Model.Document[] { doc }); session.Save(circuit); session.Save(issue); session.Flush(); } using (ISession session = sessionFactory.OpenSession()) { foreach (var item in session.CreateCriteria<Model.Circuit>().List<Model.Circuit>()) { session.Delete(item); } //this flush fails, because there is a reference to a child document from issue session.Flush(); foreach (var item in session.CreateCriteria<Model.Issue>().List<Model.Issue>()) { session.Delete(item); } session.Flush(); }

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• diff between two days, in hours

  - by Cristian Boariu

  Hi, I do not uderstand why the result of: (DateTime.Now.Subtract(user.created_time.Value.Date)).Hours is 23. where: DateTime.Now is:{3/30/2010 12:00:00 AM} and user.created_time.Value.Date is : {3/24/2010 12:00:00 AM} Does it make sense for anybody? ps: I want to select all users created in last 72 hours so i suppose that is the way i should do...

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• Trying to get distinct values from two List<int> objects

  - by Mario

  I have 2 List objects: List<int> lst1 = new List<int>(); List<int> lst2 = new List<int>(); Let's say they have values: lst1.Add(1); lst1.Add(2); lst1.Add(3); lst1.Add(4); lst2.Add(1); lst2.Add(4); I need to get an object containing the "distinct" list of both of these; so in this case the return would be List {2, 3}. Is there an easy way to do this? Or do I need to iterate through each value of the lists and compare? I am open to using ObjectQuery, LINQ, etc as these lists are coming from a database, and could potentially be several hundred to several thousand entries long. Thanks!

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• function to find common rows between more than two data frames in R

  - by biohazard

  I have 4 data frames, and would like to find the rows whose values in a certain column do not exist in any of the other data frames. I wrote this function: #function to test presence of $Name in 3 other datasets common <- function(a, b, c, d) { is.B <- is.numeric(a$Name %in% b$Name) == 1 is.C <- is.numeric(a$Name %in% c$Name) == 1 is.D <- is.numeric(a$Name %in% d$Name) == 1 t <- as.numeric(is.B & is.C & is.D) t } However, the output is always t = 0. This means that it tells me that there are no unique rows in any data sets, even though the datas frames have very different numbers of rows. Since there are no duplicate rows in any of the data frames, I should be getting t = 1 for at least some rows in the biggest dataset. Can someone figure out what I got wrong?

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• can't get two connecting strings from XML (web.config)

  - by nCdy

  XmlTextReader reader = new XmlTextReader(Window1.cfg.FSAddress); bool[] startreading = {false , false}; while (reader.Read()) { switch (reader.NodeType) { case XmlNodeType.Element: // ???? ???????? ?????????. if (startreading[0]) { if (reader.Name == "add") if (startreading[1]) { id2.Text = reader.GetAttribute(1); return; } else { id1.Text = reader.GetAttribute(1); startreading[1] = true; startreading[0] = false; } } else if (reader.Name == "connectionStrings") startreading[0] = true; break; case XmlNodeType.EndElement: if (startreading[1]) if (reader.Name == "add") startreading[0] = true; break; } } I take first one but ... then happens something strange and I'm missing second sorry for my english . btw - Im getting it not from web project.

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• Difference of two series in MySQL

  - by Brian

  I have a table with the following fields in MySQL: date, Value, Type. Type can be either exports or imports. I want a query that returns the trade deficit (exports-imports) for each month. Is this possible with a single query?

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• null pointer exception comparing two strings in java.

  - by David

  I got this error message and I'm not quite sure whats wrong: Exception in thread "main" java.lang.NullPointerException at Risk.runTeams(Risk.java:384) at Risk.blobRunner(Risk.java:220) at Risk.genRunner(Risk.java:207) at Risk.main(Risk.java:176) Here is the relevant bits of code (i will draw attention to the line numbers within the error message via comments in the code as well as inputs i put into the program while its running where relevant) public class Risk { ... public static void main (String[]arg) { String CPUcolor = CPUcolor () ; genRunner (CPUcolor) ; //line 176 ... } ... public static void genRunner (String CPUcolor) // when this method runs i select 0 and run blob since its my only option. Theres nothing wrong with this method so long as i know, this is only significant because it takes me to blob runner and because another one of our relelvent line numbers apears. { String[] strats = new String[1] ; strats[0] = "0 - Blob" ; int s = chooseStrat (strats) ; if (s == 0) blobRunner (CPUcolor) ; // this is line 207 } ... public static void blobRunner (String CPUcolor) { System.out.println ("blob Runner") ; int turn = 0 ; boolean gameOver = false ; Dice other = new Dice ("other") ; Dice a1 = new Dice ("a1") ; Dice a2 = new Dice ("a2") ; Dice a3 = new Dice ("a3") ; Dice d1 = new Dice ("d1") ; Dice d2 = new Dice ("d2") ; space (5) ; Territory[] board = makeBoard() ; IdiceRoll (other) ; String[] colors = runTeams(CPUcolor) ; //this is line 220 Card[] deck = Card.createDeck () ; System.out.println (StratUtil.canTurnIn (deck)) ; while (gameOver == false) { idler (deck) ; board = assignTerri (board, colors) ; checkBoard (board, colors) ; } } ... public static String[] runTeams (String CPUcolor) { boolean z = false ; String[] a = new String[6] ; while (z == false) { a = assignTeams () ; printOrder (a) ; boolean CPU = false ; for (int i = 0; i<a.length; i++) { if (a[i].equals(CPUcolor)) CPU = true ; //this is line 384 } if (CPU==false) { System.out.println ("ERROR YOU NEED TO INCLUDE THE COLOR OF THE CPU IN THE TURN ORDER") ; runTeams (CPUcolor) ; } System.out.println ("is this turn order correct? (Y/N)") ; String s = getIns () ; while (!((s.equals ("y")) || (s.equals ("Y")) || (s.equals ("n")) || (s.equals ("N")))) { System.out.println ("try again") ; s = getIns () ; } if (s.equals ("y") || s.equals ("Y") ) z = true ; } return a ; } ... } // This } closes the class The reason i don't think i should be getting a Null:pointerException is because in this line: a[i].equals(CPUcolor) a at index i holds a string and CPUcolor is a string. Both at this point definatly have a value neither is null. Can anyone please tell me whats going wrong?

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• one two-directed tcp socket of two one-directed? (linux, high volume, low latency)

  - by osgx

  Hello I need to send (interchange) a high volume of data periodically with the lowest possible latency between 2 machines. The network is rather fast (e.g. 1Gbit or even 2G+). Os is linux. Is it be faster with using 1 tcp socket (for send and recv) or with using 2 uni-directed tcp sockets? The test for this task is very like NetPIPE network benchmark - measure latency and bandwidth for sizes from 2^1 up to 2^13 bytes, each size sent and received 3 times at least (in teal task the number of sends is greater. both processes will be sending and receiving, like ping-pong maybe). The benefit of 2 uni-directed connections come from linux: http://lxr.linux.no/linux+v2.6.18/net/ipv4/tcp_input.c#L3847 3847/* 3848 * TCP receive function for the ESTABLISHED state. 3849 * 3850 * It is split into a fast path and a slow path. The fast path is 3851 * disabled when: ... 3859 * - Data is sent in both directions. Fast path only supports pure senders 3860 * or pure receivers (this means either the sequence number or the ack 3861 * value must stay constant) ... 3863 * 3864 * When these conditions are not satisfied it drops into a standard 3865 * receive procedure patterned after RFC793 to handle all cases. 3866 * The first three cases are guaranteed by proper pred_flags setting, 3867 * the rest is checked inline. Fast processing is turned on in 3868 * tcp_data_queue when everything is OK. All other conditions for disabling fast path is false. And only not-unidirected socket stops kernel from fastpath in receive

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