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• File sizing issue in DOS/FAT

  - by Heather

  I've been tasked with writing a data collection program for a Unitech HT630, which runs a proprietary DOS operating system that can run executables compiled for 16-bit MS DOS with some restrictions. I'm using the Digital Mars C/C++ compiler, which is working well thus far. One of the application requirements is that the data file must be human-readable plain text, meaning the file can be imported into Excel or opened by Notepad. I'm using a variable length record format much like CSV that I've successfully implemented using the C standard library file I/O functions. When saving a record, I have to calculate whether the updated record is larger or smaller than the version of the record currently in the data file. If larger, I first shift all records immediately after the current record forward by the size difference calculated before saving the updated record. EOF is extended automatically by the OS to accommodate the extra data. If smaller, I shift all records backwards by my calculated offset. This is working well, however I have found no way to modify the EOF marker or file size to ignore the data after the end of the last record. Most of the time records will grow in size because the data collection program will be filling some of the empty fields with data when saving a record. Records will only shrink in size when a correction is made on an existing entry, or on a normal record save if the descriptive data in the record is longer than what the program reads in memory. In the situation of a shrinking record, after the last record in the file I'm left with whatever data was sitting there before the shift. I have been writing an EOF delimiter into the file after a "shrinking record save" to signal where the end of my records are and space-filling the remaining data, but then I no longer have a clean file until a "growing record save" extends the size of the file over the space-filled area. The truncate() function in unistd.h does not work (I'm now thinking this is for *nix flavors only?). One proposed solution I've seen involves creating a second file and writing all the data you wish to save into that file, and then deleting the original. Since I only have 4MB worth of disk space to use, this works if the file size is less than 2MB minus the size of my program executable and configuration files, but would fail otherwise. It is very likely that when this goes into production, users would end up with a file exceeding 2MB in size. I've looked at Ralph Brown's Interrupt List and the interrupt reference in IBM PC Assembly Language and Programming and I can't seem to find anything to update the file size or similar. Is reducing a file's size without creating a second file even possible in DOS?

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• Catch Multiple Custom Exceptions? - C++

  - by Alex

  Hi all, I'm a student in my first C++ programming class, and I'm working on a project where we have to create multiple custom exception classes, and then in one of our event handlers, use a try/catch block to handle them appropriately. My question is: How do I catch my multiple custom exceptions in my try/catch block? GetMessage() is a custom method in my exception classes that returns the exception explanation as a std::string. Below I've included all the relevant code from my project. Thanks for your help! try/catch block // This is in one of my event handlers, newEnd is a wxTextCtrl try { first.ValidateData(); newEndT = first.ComputeEndTime(); *newEnd << newEndT; } catch (// don't know what do to here) { wxMessageBox(_(e.GetMessage()), _("Something Went Wrong!"), wxOK | wxICON_INFORMATION, this);; } ValidateData() Method void Time::ValidateData() { int startHours, startMins, endHours, endMins; startHours = startTime / MINUTES_TO_HOURS; startMins = startTime % MINUTES_TO_HOURS; endHours = endTime / MINUTES_TO_HOURS; endMins = endTime % MINUTES_TO_HOURS; if (!(startHours <= HOURS_MAX && startHours >= HOURS_MIN)) throw new HourOutOfRangeException("Beginning Time Hour Out of Range!"); if (!(endHours <= HOURS_MAX && endHours >= HOURS_MIN)) throw new HourOutOfRangeException("Ending Time Hour Out of Range!"); if (!(startMins <= MINUTE_MAX && startMins >= MINUTE_MIN)) throw new MinuteOutOfRangeException("Starting Time Minute Out of Range!"); if (!(endMins <= MINUTE_MAX && endMins >= MINUTE_MIN)) throw new MinuteOutOfRangeException("Ending Time Minute Out of Range!"); if(!(timeDifference <= P_MAX && timeDifference >= P_MIN)) throw new PercentageOutOfRangeException("Percentage Change Out of Range!"); if (!(startTime < endTime)) throw new StartEndException("Start Time Cannot Be Less Than End Time!"); } Just one of my custom exception classes, the others have the same structure as this one class HourOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type HourOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~HourOutOfRangeException() {} private: string message; };

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• Array within Form collecting multiple values with the same name possible?

  - by JM4

  Good afternoon, I will first start with the goal I am trying to accomplish and then give a very basic sample of what I need to do. Goal Instead of collecting several variables and naming them with keys individually, I have decided to give in and use an array structure to handle all inputs of the same type and rules. Once I have the variables, I will validate against them and if 'ok' store them in a MySQL table. The table will hold consumer information and will need to store multiple rows of the same type of information. First Pass I will leave out the validation portion of this question because I feel I need to first understand the basics. <form action="?" method="POST" name="Form"> Member 1 First Name:<input type="text" name="MemberFirstName[]" /><br /> Member 1 Last Name: <input type="text" name="MemberLastName[]" /><br /> Member 1 Email: <input type="text" name="MemberEmail[]" /><br /> Member 2 First Name:<input type="text" name="MemberFirstName[]" /><br /> Member 2 Last Name: <input type="text" name="MemberLastName[]" /><br /> Member 2 Email: <input type="text" name="MemberEmail[]" /><br /> Member 3 First Name:<input type="text" name="MemberFirstName[]" /><br /> Member 3 Last Name: <input type="text" name="MemberLastName[]" /><br /> Member 3 Email: <input type="text" name="MemberEmail[]" /><br /> <input type="submit" name="submit" value="Continue" /> </form> I am hoping that each input given for First Name (a required field) will generate a unique key for that particular entry and not overwrite any data entered. Because I am carrying information from page to page (checkout form), I am turning the POST variables into SESSION variables then storing in a mysql database in the end. My hope is to have: <?php $conn = mysql_connect("localhost", "username", "password"); mysql_select_db("DBname",$conn); $sql = "INSERT INTO tablename VALUES ('$_SESSION[Member1FirstName]', '$_SESSION[Member1LastName]', '$_SESSION[Member1Email]', '$_SESSION[Member2FirstName]', '$_SESSION[Member2LastName]', '$_SESSION[Member2Email]', '$_SESSION[Member1FirstName]', '$_SESSION[Member3LastName]', '$_SESSION[Member3Email]')"; $result = mysql_query($sql, $conn) or die(mysql_error()); Header ("Location: completed.php"); ?> Where Member1, Member2, and Member3 values will appear on their own row within the table. I KNOW my code is wrong but I am giving a first shot at the overall business purpose I am trying to achieve and trying to learn how to code the right way. I am very, very new to programming so any 'baby advice' is greatly appreciated.

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• global static boolean pointer causes segmentation fault using pthread

  - by asksw0rder

  New to pthread programming, and stuck on this error when working on a C++&C mixed code. What I have done is to call the c code in the thread created by the c++ code. There is a static boolean pointer used in the thread and should got free when the thread finishes. However I noticed that every time when the program processed into the c function, the value of the boolean pointer would be changed and the segmentation fault then happened due to the free(). Detail code is as follows: static bool *is_center; // omit other codes in between ... void streamCluster( PStream* stream) { // some code here ... while(1){ // some code here ... is_center = (bool*)calloc(points.num,sizeof(bool)); // start the parallel thread here. // the c code is invoked in this function. localSearch(&points,kmin, kmax,&kfinal); // parallel free(is_center); } And the function using parallel is as follows (my c code is invoked in each thread): void localSearch( Points* points, long kmin, long kmax, long* kfinal ) { pthread_barrier_t barrier; pthread_t* threads = new pthread_t[nproc]; pkmedian_arg_t* arg = new pkmedian_arg_t[nproc]; pthread_barrier_init(&barrier,NULL,nproc); for( int i = 0; i < nproc; i++ ) { arg[i].points = points; arg[i].kmin = kmin; arg[i].kmax = kmax; arg[i].pid = i; arg[i].kfinal = kfinal; arg[i].barrier = &barrier; pthread_create(threads+i,NULL,localSearchSub,(void*)&arg[i]); } for ( int i = 0; i < nproc; i++) { pthread_join(threads[i],NULL); } delete[] threads; delete[] arg; pthread_barrier_destroy(&barrier); } Finally the function calling my c code: void* localSearchSub(void* arg_) { // omit some initialize code... // my code begin_papi_thread(&eventSet); // Processing k-means, omit codes. // is_center value will be updated correctly // my code end_papi_thread(&eventSet); // when jumping into this, error happens return NULL; } And from gdb, what I have got for the is_center is: Breakpoint 2, localSearchSub (arg_=0x600000000000bc40) at streamcluster.cpp:1711 1711 end_papi_thread(&eventSet); (gdb) s Hardware watchpoint 1: is_center Old value = (bool *) 0x600000000000bba0 New value = (bool *) 0xa93f3 0x400000000000d8d1 in localSearchSub (arg_=0x600000000000bc40) at streamcluster.cpp:1711 1711 end_papi_thread(&eventSet); Any suggestions? Thanks in advance!

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• Trying to style the first tbody different than others without introducing another class.

  - by mwiik

  I have a table with multiple tbody's, each of which has a classed row, and I want it so that the classed row in the first tbody has style differences, but am unable to get tbody:first-child to work in any browser. Perhaps I am missing something, or maybe there is a workaround. Ideally, I would like to provide the programmers with a single tbody section they can use as a template, but will otherwise have to add a class to the first tbody, making for an extra test in the programming. The html is straightforward: <tbody class="subGroup"> <tr class="subGroupHeader"> <th colspan="8">All Grades: Special Education</th> <td class="grid" colspan="2"><!-- contains AMO line --></td> <td><!-- right 100 --></td> </tr> <tr>...</tr> <!-- several more rows of data --> </tbody> There are several tbody's per table. I want to style the th and td's within tr.subGroupHeader in the very first tbody differently than the rest. Just to illustrate, I want to add a border-top to the tr.subGroupHeader cells. The tr.subGroupHeader will be styled with a border-top, such as: table.databargraph.continued tr.subGroupHeader th, table.databargraph.continued tr.subGroupHeader td { border-top: 6px solid red; } For the first tbody, I am trying: table.databargraph.continued tbody:first-child tr.subGroupHeader th { border-top: 6px solid blue ; } However, this doesn't seem to work in any browser (I've tested in Safari, Opera, Firefox, and PrinceXML, all on my Mac) Curiously, the usually excellent Xyle Scope tool indicates that the blue border should be taking precedence, though it obviously is not. See the screenshot at http://s3.amazonaws.com/ember/kUD8DHrz06xowTBK3qpB2biPJrLWTZCP_o.png This screenshot shows (top left) the American Indian th is selected, and (bottom right), shows (via black instead of gray text for the css declaration), that, indeed, the blue border should be given precedence. Yet the border is red. I may be missing something fundamental, like pseudo-classes not working for tbodys at all... This really only needs to work in PrinceXML, and maybe Safari so I can see what I'm doing with webkit-based css tools. Note I did try a selector like tr.subGroupHeader:first-child, but such tr's apparently consider the tbody the parent (as I would suspect), thus made every border blue. Thanks...

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• Any socket programmers out there? How can I obtain the IPv4 address of the client?

  - by Dr Dork

  Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code setup to listen for incoming TCP connection requests from clients after the parent socket has been created and is set to listen... int sockfd, newfd; unsigned int len; socklen_t sin_size; char msg[]="Test message sent"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char ip[INET6_ADDRSTRLEN]; . . //parent socket creation and listen code omitted for simplicity . //wait for connection requests from clients while(1) { //Returns the socketID and address of client connecting to socket if( ( newfd = accept(sockfd, (struct sockaddr *)&client, &len) ) == -1 ){ perror("Accept"); exit(-1); } if( (rv = recv(newfd, buf, MAXLEN-1, 0 )) == -1) { perror("Recv"); exit(-1); } struct sockaddr_in *clientAddr = ( struct sockaddr_in *) get_in_addr((struct sockaddr *)&client); inet_ntop(client.ss_family, clientAddr, ip, sizeof ip); printf("Receive from %s: query type is %s\n", ip, buf); if( ( st = send(newfd, msg, strlen(msg), 0)) == -1 ) { perror("Send"); exit(-1); } //ntohs is used to avoid big-endian and little endian compatibility issues printf("Send %d byte to port %d\n", ntohs(clientAddr->sin_port) ); close(newfd); } } I found the get_in_addr function online and placed it at the top of my code and use it to obtain the IP address of the client connecting... // get sockaddr, IPv4 or IPv6: void *get_in_addr(struct sockaddr *sa) { if (sa->sa_family == AF_INET) { return &(((struct sockaddr_in*)sa)->sin_addr); } return &(((struct sockaddr_in6*)sa)->sin6_addr); } but the function always returns the IPv6 IP address since thats what the sa_family property is set as. My question is, is the IPv4 IP address stored anywhere in the data I'm using and, if so, how can I access it? Thanks so much in advance for all your help!

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• Windows 8, NVIDIA graphics recognition fails

  - by Roy Grubb

  I just installed Windows 8 Pro OEM 64-bit (clean install) and it won't properly recognize my graphics adapter. When I installed Win8, it automatically installed the BasicDisplay.sys driver dated 6/21/2006. 6.2.9200.16384 (win8_rtm.120725-1247). Hardware - Mobo:MSi G41M-P33 Combo CPU:Intel CoreDuo 6600 Graphics:NVIDIA GeForce 9400GT *OS* - Windows 8 Pro 64-bit OEM The graphics adapter worked fine in Windows XP. The PC is a generic box, bought locally and its mobo failed recently, so I replaced it with the G41M. Microsoft wouldn't let me re-activate Windows XP with a different mobo, so I installed Win8, which appears to work except as described next. Win8 only partially recognizes the graphics adapter and won't allow NVIDIA latest driver installer to see that it's an NVIDIA card. As a result, OpenGL doesn't work, and this is needed by the software I most use. Other than that the graphics look OK. When I say 'partially recognizes', I mean that via the Control Panel, I can see that the adapter is described as NVIDIA, but the driver remains stuck at Microsoft Basic Display Adapter no matter what I try, including "Update driver..." in adapter properties. Display Screen Resolution Advanced Settings Adapter shows: Adapter Type: Microsoft Basic Display Adapter Chip Type: NVIDIA DAC Type: NVIDIA Corporation Bios Information: G27 Board - p381n17 Don't know what this means ... no mention of 9400GT Total Available Graphics Memory: 256 MB Dedicated Video Memory: 0 MB In fact the adapter has 512MB on-board video memory. System Video Memory: 0 MB Shared System Memory: 256 MB And Control Panel Device Manager Display adapters just shows Microsoft Basic Display Adapter. No other graphics adapter, and no unknown device or yellow question mark. What I have tried so far: 1. Cleared CMOS and reset. Updated BIOS and all mobo drivers as follows: 1st I used Driver Reviver to see if any driver updates were required. It found some but I didn't use that to get the drivers. Then I switched to MSi's own mobo driver utility Live Update 5. This also showed the board needed to update several so I used it to fetch the new drivers. After that it showed that everything was up to date and I checked with Driver Reviver again, which also reported no drivers now needed updating. Rebooted. Went to the NVIDIA site to get the latest graphics adapter driver. Their auto-detect "Option 2: Automatically find drivers for my NVIDIA products" said "The NVIDIA Smart Scan was unable to evaluate your system hardware. Please use Option 1 to manually find drivers for your NVIDIA products." So I downloaded 310.70-desktop-win8-win7-winvista-64bit-international-whql.exe, which lists 9400 GT under supported products, but when I run it, it says: "NVIDIA Installer cannot continue This graphics driver could not find compatible graphics hardware." Connected the display to the on-board Intel graphics (G41 Intel Express), removed the NVIDIA card and rebooted, changed to internal graphics in CMOS. Again it installs the MS Basic Display Adapter, and can't properly run my s/w that needs OpenGL. It runs on other machines with Intel Express graphics (WinXP and 7) Shut down and pulled out the power cord. Held start button to discharge all capacitors. Removed and re-inserted NVIDIA adapter in PCI-E slot and made sure properly seated. Connected the monitor to the card, screwed plug to socket. Reconnected power cord. Started and checked in BIOS that Primary Graphics Adapter was set to PCI-E. Started Windows. Uninstalled MS Basic Display Adapter in Device Manager. Screen blanks briefly, reappears. No Graphics adapter entry was then visible in Device Manager. Restarted PC. MS Basic Display Adapter Visible again in Device Manager. Clicked in Device Manager View Show hidden devices. No other graphics adapter appears, no unknown devices. Rebooted. Tried Scan for Hardware changes. None detected. Tried right-click on MS Basic Display Adapter Properties Driver Update Driver... Search automatically. It replied that it had determined driver was up to date. I checked that there were no graphic driver-related entries in Programs and Features that I could delete (none). Searched for any other drivers with nvidia in their name and deleted them, just keeping the 306.97 installer exe file. Did a Windows Update. Ran GPU-Z which shows (main items): Microsoft Basic Display Adapter GPU G72 BIOS 5.72.22.76.88 Device ID 10DE - 01D5 DDR2 Bus Width 32 Bit Memory size 64MB Driver Version nvlddmkm 6.2.9200.16384 (ForceWare 0.00) / Win8 64 NVIDIA SLI Unknown in the drop-down at the foot, "Microsoft Basic Display Adapter" is the only option If I swap hard disks in that machine to one with a Ubuntu 10.4 installation (originally installed on the same PC), lspci shows "VGA compatible controller as NVIDIA Corporation Device 01d5 (rev a1) (prog-if 00 [VGA controller])" and "kernel driver in use: nvidia" I'm out of ideas for new things to try and would be really grateful of suggestions. Thanks!

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• Python File Search Line And Return Specific Number of Lines after Match

  - by Simos Anderson

  I have a text file that has lines representing some data sets. The file itself is fairly long but it contains certain sections of the following format: Series_Name INFO Number of teams : n1 | Team | # | wins | | TeamName1 | x | y | . . . | TeamNamen1 | numn | numn | Some Irrelevant lines Series_Name2 INFO Number of teams : n1 | Team | # | wins | | TeamName1 | num1 | num2 | . where each section has a header that begins with the Series_Name. Each Series_Name is different. The line with the header also includes the number of teams in that series, n1. Following the header line is a set of lines that represents a table of data. For each series there are n1+1 rows in the table, where each row shows an individual team name and associated stats. I have been trying to implement a function that will allow the user to search for a Team name and then print out the line in the table associated with that team. However, certain team names show up under multiple series. To resolve this, I am currently trying to write my code so that the user can search for the header line with series name first and then print out just the following n1+1 lines that represent the data associated with the series. Here's what I have come up with so far: import re print fname = raw_input("Enter filename: ") seriesname = raw_input("Enter series: ") def findcounter(fname, seriesname): logfile = open(fname, "r") pat = 'INFO Number of teams :' for line in logfile: if seriesname in line: if pat in line: s=line pattern = re.compile(r"""(?P<name>.*?) #starting name \s*INFO #whitespace and success \s*Number\s*of\s*teams #whitespace and strings \s*\:\s*(?P<n1>.*)""",re.VERBOSE) match = pattern.match(s) name = match.group("name") n1 = int(match.group("n1")) print name + " has " + str(n1) + " teams" lcount = 0 for line in logfile: if line.startswith(name): if pat in line: while lcount <= n1: s.append(line) lcount += 1 return result The first part of my code works; it matches the header line that the person searches for, parses the line, and then prints out how many teams are in that series. Since the header line basically tells me how many lines are in the table, I thought that I could use that information to construct a loop that would continue printing each line until a set counter reached n1. But I've tried running it, and I realize that the way I've set it up so far isn't correct. So here's my question: How do you return a number of lines after a matched line when given the number of desired lines that follow the match? I'm new to programming, and I apologize if this question seems silly. I have been working on this quite diligently with no luck and would appreciate any help.

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• Components are not longer resizable after moving

  - by Junior Software Developer

  Hi guys My question relates to swing programming. I want to enlarge a component (component x) by removing it from its parent panel (component a) and adding it in one of component a's parent (component b). Before that, I call setVisible(false) on all components in b. After that I want to make this back by removing it from b and adding on a. After that all components are not longer resizable. Why that? An easy example: import java.awt.BorderLayout; import java.awt.Color; import java.awt.Component; import java.awt.Dimension; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JTabbedPane; public class SwingTest { private static ViewPanel layer1; private static JFrame frame; private static JTabbedPane tabbedPane; private static ViewPanel root; public static void main(String[] args) { frame = new JFrame(); frame.setLayout(new BorderLayout()); frame.setMinimumSize(new Dimension(800, 600)); root = new ViewPanel(); root.setBackground(Color.blue); root.setPreferredSize(new Dimension(400, 600)); root.setLayout(new BorderLayout()); root.add(new JLabel("blue area")); layer1 = new ViewPanel(); layer1.setBackground(Color.red); layer1.setPreferredSize(new Dimension(400, 600)); layer1.setLayout(new BorderLayout()); tabbedPane = new JTabbedPane(); tabbedPane.add("A", new JLabel("A label")); tabbedPane.setPreferredSize(new Dimension(400, 600)); layer1.add(tabbedPane); root.add(layer1); frame.add(root, BorderLayout.NORTH); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); frame.pack(); frame.setVisible(true); Thread t = new Thread() { @Override public void run() { try { Thread.sleep(8000); System.out.println("start"); for (Component c : root.getComponents()) { c.setVisible(false); } layer1.remove(tabbedPane); root.add(tabbedPane); Thread.sleep(8000); root.remove(tabbedPane); layer1.add(tabbedPane); for (Component c : root.getComponents()) { c.setVisible(true); c.repaint(); } } catch (InterruptedException e) { //... } } }; t.start(); } }

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• how i can use SAX parser

  - by moustafa

  This is what the result should look like when i parse it through a SAX parser http://img13.imageshack.us/img13/6950/75914446.jpg This is the XML source code from which i need to generate the display: <orders> <order> <count>37</count> <price>49.99</price> <book> <isbn>0130897930</isbn> <title>Core Web Programming Second Edition</title> <authors> <count>2</count> <author>Marty Hall</author> <author>Larry Brown</author> </authors> </book> </order> <order> <count>1</count> <price>9.95</price> <yacht> <manufacturer>Luxury Yachts, Inc.</manufacturer> <model>M-1</model> <standardFeatures oars="plastic" lifeVests="none">false</standardFeatures> </yacht> </order> <order> <count>3</count> <price>22.22</price> <book> <isbn>B000059Z4H</isbn> <title>Harry Potter and the Order of the Phoenix</title> <authors> <count>1</count> <author>J.K. Rowling</author> </authors> </book> </order> i really have no clue how to code the functions but i have just set up the parser $xmlParser = xml_parser_create("UTF-8"); xml_parser_set_option($xmlParser, XML_OPTION_CASE_FOLDING, false); xml_set_element_handler($xmlParser, 'startElement', 'endElement'); xml_set_character_data_handler($xmlParser, 'HandleCharacterData'); $fileName = 'orders.xml'; if (!($fp = fopen($fileName, 'r'))){ die('Cannot open the XML file: ' . $fileName); } while ($data = fread($fp, 4096)){ $parsedOkay = xml_parse($xmlParser, $data, feof($fp)); if (!$parsedOkay){ print ("There was an error or the parser was finished."); break; } } xml_parser_free($xmlParser); function startElement($xmlParser, $name, $attribs) { } function endElement($parser, $name) { } function HandleCharacterData($parser, $data) { }

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• Why does Scala apply thunks automatically, sometimes?

  - by Anonymouse

  At just after 2:40 in ShadowofCatron's Scala Tutorial 3 video, it's pointed out that the parentheses following the name of a thunk are optional. "Buh?" said my functional programming brain, since the value of a function and the value it evaluates to when applied are completely different things. So I wrote the following to try this out. My thought process is described in the comments. object Main { var counter: Int = 10 def f(): Int = { counter = counter + 1; counter } def runThunk(t: () => Int): Int = { t() } def main(args: Array[String]): Unit = { val a = f() // I expect this to mean "apply f to no args" println(a) // and apparently it does val b = f // I expect this to mean "the value f", a function value println(b) // but it's the value it evaluates to when applied to no args println(b) // and the evaluation happens immediately, not in the call runThunk(b) // This is an error: it's not println doing something funny runThunk(f) // Not an error: seems to be val doing something funny } }   To be clear about the problem, this Scheme program (and the console dump which follows) shows what I expected the Scala program to do. (define counter (list 10)) (define f (lambda () (set-car! counter (+ (car counter) 1)) (car counter))) (define runThunk (lambda (t) (t))) (define main (lambda args (let ((a (f)) (b f)) (display a) (newline) (display b) (newline) (display b) (newline) (runThunk b) (runThunk f)))) > (main) 11 #<procedure:f> #<procedure:f> 13   After coming to this site to ask about this, I came across this answer which told me how to fix the above Scala program: val b = f _ // Hey Scala, I mean f, not f() But the underscore 'hint' is only needed sometimes. When I call runThunk(f), no hint is required. But when I 'alias' f to b with a val then apply it, it doesn't work: the evaluation happens in the val; and even lazy val works this way, so it's not the point of evaluation causing this behaviour.   That all leaves me with the question: Why does Scala sometimes automatically apply thunks when evaluating them? Is it, as I suspect, type inference? And if so, shouldn't a type system stay out of the language's semantics? Is this a good idea? Do Scala programmers apply thunks rather than refer to their values so much more often that making the parens optional is better overall? Examples written using Scala 2.8.0RC3, DrScheme 4.0.1 in R5RS.

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• Should I add try/catch around when casting on an attribute of JSP implicit object?

  - by Michael Mao

  Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

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• Java app makes screen display unresponsive after 10 minutes of user idle time

  - by Ross

  I've written a Java app that allows users to script mouse/keyboard input (JMacro, link not important, only for the curious). I personally use the application to automate character actions in an online game overnight while I sleep. Unfortunately, I keep coming back to the computer in the morning to find it unresponsive. Upon further testing, I'm finding that my application causes the computer to become unresponsive after about 10 minutes of user idle time (even if the application itself it simulating user activity). I can't seem to pin-point the issue, so I'm hoping somebody else might have a suggestion of where to look or what might be causing the issue. The relevant symptoms and characteristics: Unresponsiveness occurs after user is idle for 10 minutes User can still move the mouse pointer around the screen Everything but the mouse appears frozen... mouse clicks have no effect and no applications update their displays, including the Windows 7 desktop I left the task manager up along the with the app overnight so I could see the last task manager image before the screen freezes... the Java app is at normal CPU/Memory usage and total CPU usage is only ~1% After moving the mouse (in other words, the user comes back from being idle), the screen image starts updating again within 30 minutes (this is very hit and miss... sometimes 10 minutes, sometimes no results after two hours) User can CTRL-ALT-DEL to get to Windows 7's CTRL-ALT-DEL screen (after a 30 second pause). User is still able to move mouse pointer, but clicking any of the button options causes the screen to appear to freeze again On some very rare occasions, the system never freezes, and I come back to it in the morning with full responsiveness The Java app automatically stops input scripting in the middle of the night, so Windows 7 detects "real" idleness and turns the monitors into Standby mode... which they successfully come out of upon manually moving the mouse in the morning when I wake up, even though the desktop display still appears frozen Given the symptoms and characteristics of the issue, it's as if the Java app is causing the desktop display of the logged in user to stop updating, including any running applications. Programming concepts and Java packages used: Multi-threading Standard out and err are rerouted to a javax.swing.JTextArea The application uses a Swing GUI awt.Robot (very heavily used) awt.PointerInfo awt.MouseInfo System Specs: Windows 7 Professional Java 1.6.0 u17 In conclusion, I should stress that I'm not looking for any specific solutions, as I'm not asking a very specific question. I'm just wondering if anybody has run into a similar problem when using the Java libraries that I'm using. I would also gladly appreciate any suggestions for things to try to attempt to further pinpoint what is causing my problem. Thanks! Ross PS, I'll post an update/answer if I manage to stumble across anything else while I continue to debug this.

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• How can I remove rows with unique values? As in only keeping rows with duplicate values?

  - by user1456405

  Here's the conundrum, I'm a complete and utter noob when it comes to programming. I understand the basics, but am still learning javascript. I have a spreadsheet of surveys, in which I need to see how particular users have varied over time. As such, I need to disregard all rows with unique values in a particular column. The data looks like this: Response Date Response_ID Account_ID Q.1 10/20/2011 12:03:43 PM 23655956 1168161 8 10/20/2011 03:52:57 PM 23660161 1168152 0 10/21/2011 10:55:54 AM 23672903 1166121 7 10/23/2011 04:28:16 PM 23694471 1144756 9 10/25/2011 06:30:52 AM 23732674 1167449 7 10/25/2011 07:52:28 AM 23734597 1087618 5 I've found a way to do so in VBA, which sucks as I have to use excel, per below: Sub Del_Unique() Application.ScreenUpdating = False Columns("B:B").Insert Shift:=xlToRight Columns("A:A").Copy Destination:=Columns("B:B") i = Application.CountIf(Range("A:A"), "<>") + 50 If i > 65536 Then i = 65536 Do If Application.CountIf(Range("B:B"), Range("A" & i)) = 1 Then Rows(i).Delete End If i = i - 1 Loop Until i = 0 Columns("B:B").Delete Application.ScreenUpdating = True End Sub But that requires mucking about. I'd really like to do it in Google Spreadsheets with a script that won't have to be changed. Closest I can get is retrieving all duplicate user ids from the range, but can't associate that with the row. That code follows: function findDuplicatesInSelection() { var activeRange = SpreadsheetApp.getActiveRange(); var values = activeRange.getValues(); // values that appear at least once var once = {}; // values that appear at least twice var twice = {}; // values that appear at least twice, stored in a pretty fashion! var final = []; for (var i = 0; i < values.length; i++) { var inner = values[i]; for (var j = 0; j < inner.length; j++) { var cell = inner[j]; if (cell == "") continue; if (once.hasOwnProperty(cell)) { if (!twice.hasOwnProperty(cell)) { final.push(cell); } twice[cell] = 1; } else { once[cell] = 1; } } } if (final.length == 0) { Browser.msgBox("No duplicates found"); } else { Browser.msgBox("Duplicates are: " + final); } } Anyhow, sorry if this is the wrong place or format, but half of what I've found so far has been from stack, I thought it was a good place to start. Thanks!

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• Python/Biomolecular Physics- Trying to code a simple stochastic simulation of a system exhibiting co

  - by user359597

  *edited 6/17/10 I'm trying to understand how to improve my code (make it more pythonic). Also, I'm interested in writing more intuitive 'conditionals' that would describe scenarios that are commonplace in biochemistry. The conditional criteria in the below program is explained in Answer #2, but I am not satisfied with it- it is correct, but isn't obvious and isn't easy to implement for more complicated conditional scenarios. Ideas welcome. Comments/criticisms welcome. First posting experience @ stackoverflow- please comment on etiquette if needed. The code generates a list of values that are the solution to the following exercise: "In a programming language of your choice, implement Gillespie’s First Reaction Algorithm to study the temporal behaviour of the reaction A---B in which the transition from A to B can only take place if another compound, C, is present, and where C dynamically interconverts with D, as modelled in the Petri-net below. Assume that there are 100 molecules of A, 1 of C, and no B or D present at the start of the reaction. Set kAB to 0.1 s-1 and both kCD and kDC to 1.0 s-1. Simulate the behaviour of the system over 100 s." def sim(): # Set the rate constants for all transitions kAB = 0.1 kCD = 1.0 kDC = 1.0 # Set up the initial state A = 100 B = 0 C = 1 D = 0 # Set the start and end times t = 0.0 tEnd = 100.0 print "Time\t", "Transition\t", "A\t", "B\t", "C\t", "D" # Compute the first interval transition, interval = transitionData(A, B, C, D, kAB, kCD, kDC) # Loop until the end time is exceded or no transition can fire any more while t <= tEnd and transition >= 0: print t, '\t', transition, '\t', A, '\t', B, '\t', C, '\t', D t += interval if transition == 0: A -= 1 B += 1 if transition == 1: C -= 1 D += 1 if transition == 2: C += 1 D -= 1 transition, interval = transitionData(A, B, C, D, kAB, kCD, kDC) def transitionData(A, B, C, D, kAB, kCD, kDC): """ Returns nTransition, the number of the firing transition (0: A->B, 1: C->D, 2: D->C), and interval, the interval between the time of the previous transition and that of the current one. """ RAB = kAB * A * C RCD = kCD * C RDC = kDC * D dt = [-1.0, -1.0, -1.0] if RAB > 0.0: dt[0] = -math.log(1.0 - random.random())/RAB if RCD > 0.0: dt[1] = -math.log(1.0 - random.random())/RCD if RDC > 0.0: dt[2] = -math.log(1.0 - random.random())/RDC interval = 1e36 transition = -1 for n in range(len(dt)): if dt[n] > 0.0 and dt[n] < interval: interval = dt[n] transition = n return transition, interval if __name__ == '__main__': sim()

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• Problem while adding a new value to a hashtable when it is enumerated

  - by karthik

  `hi I am doing a simple synchronous socket programming,in which i employed twothreads one for accepting the client and put the socket object into a collection,other thread will loop through the collection and send message to each client through the socket object. the problem is 1.i connect to clients to the server and start send messages 2.now i want to connect a new client,while doing this i cant update the collection and add a new client to my hashtable.it raises an exception "collection modified .Enumeration operation may not execute" how to add a NEW value without having problems in a hashtable. private void Listen() { try { //lblStatus.Text = "Server Started Listening"; while (true) { Socket ReceiveSock = ServerSock.Accept(); //keys.Clear(); ConnectedClients = new ListViewItem(); ConnectedClients.Text = ReceiveSock.RemoteEndPoint.ToString(); ConnectedClients.SubItems.Add("Connected"); ConnectedList.Items.Add(ConnectedClients); ClientTable.Add(ReceiveSock.RemoteEndPoint.ToString(), ReceiveSock); //foreach (System.Collections.DictionaryEntry de in ClientTable) //{ // keys.Add(de.Key.ToString()); //} //ClientTab.Add( //keys.Add( } //lblStatus.Text = "Client Connected Successfully."; } catch (Exception ex) { MessageBox.Show(ex.Message); } } private void btn_receive_Click(object sender, EventArgs e) { Thread receiveThread = new Thread(new ThreadStart(Receive)); receiveThread.IsBackground = true; receiveThread.Start(); } private void Receive() { while (true) { //lblMsg.Text = ""; byte[] Byt = new byte[2048]; //ReceiveSock.Receive(Byt); lblMsg.Text = Encoding.ASCII.GetString(Byt); } } private void btn_Send_Click(object sender, EventArgs e) { Thread SendThread = new Thread(new ThreadStart(SendMsg)); SendThread.IsBackground = true; SendThread.Start(); } private void btnlist_Click(object sender, EventArgs e) { //Thread ListThread = new Thread(new ThreadStart(Configure)); //ListThread.IsBackground = true; //ListThread.Start(); } private void SendMsg() { while (true) { try { foreach (object SockObj in ClientTable.Keys) { byte[] Tosend = new byte[2048]; Socket s = (Socket)ClientTable[SockObj]; Tosend = Encoding.ASCII.GetBytes("FirstValue&" + GenerateRandom.Next(6, 10).ToString()); s.Send(Tosend); //ReceiveSock.Send(Tosend); Thread.Sleep(300); } } catch (Exception ex) { MessageBox.Show(ex.Message); } } }

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• Ubuntu cannot access internet, LAN is fine

  - by Kevin Southworth

  I have an Ubuntu 8.04 LTS server that is directly connected to our Comcast Business Gateway modem and I have configured it with 1 of our 5 allotted Static IPs. My other machines on our LAN can connect to this server (via ssh, web, ping, etc.) but I cannot access this server from outside our network, and this machine cannot get out to the internet either (ping google.com fails with unknown host). Here is my /etc/networking/interfaces file: auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 173.162.54.19 netmask 255.255.255.248 broadcast 173.162.54.23 gateway 173.162.54.22 and my /etc/resolv.conf: nameserver 68.87.77.130 nameserver 68.87.72.130 output from sudo route -n: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 173.162.54.16 0.0.0.0 255.255.255.248 U 0 0 0 eth0 0.0.0.0 173.162.54.22 0.0.0.0 UG 100 0 0 eth0 I have a Windows 2008 machine with an almost identical Static IP, static DNS setup and it works correctly, can access it within the LAN and also from public internet, the Windows machine and the Ubuntu machine are both directly connected to the Comcast Business Gateway. I have tried rebooting Ubuntu, rebooting my Comcast modem, but nothing seems to make it work. I'm an Ubuntu noob, is there some other config I need to apply to make this work? UPDATE: Yes I am able to ping my default gateway 173.162.54.22 output of iptables --list -n: Chain INPUT (policy DROP) target prot opt source destination ufw-before-input all -- 0.0.0.0/0 0.0.0.0/0 ufw-after-input all -- 0.0.0.0/0 0.0.0.0/0 Chain FORWARD (policy DROP) target prot opt source destination ufw-before-forward all -- 0.0.0.0/0 0.0.0.0/0 ufw-after-forward all -- 0.0.0.0/0 0.0.0.0/0 Chain OUTPUT (policy ACCEPT) target prot opt source destination ufw-before-output all -- 0.0.0.0/0 0.0.0.0/0 ufw-after-output all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-after-forward (1 references) target prot opt source destination LOG all -- 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix `[UFW BLOCK FORWARD]: ' RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-after-input (1 references) target prot opt source destination RETURN udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:137 RETURN udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:138 RETURN tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:139 RETURN tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:445 RETURN udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:67 RETURN udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:68 LOG all -- 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix `[UFW BLOCK INPUT]: ' RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-after-output (1 references) target prot opt source destination RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-before-forward (1 references) target prot opt source destination ufw-user-forward all -- 0.0.0.0/0 0.0.0.0/0 RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-before-input (1 references) target prot opt source destination ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED DROP all -- 0.0.0.0/0 0.0.0.0/0 ctstate INVALID ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 3 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 4 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 11 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 12 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 8 ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp spt:67 dpt:68 ufw-not-local all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 224.0.0.0/4 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 224.0.0.0/4 ufw-user-input all -- 0.0.0.0/0 0.0.0.0/0 RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-before-output (1 references) target prot opt source destination ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW,RELATED,ESTABLISHED ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 state NEW,RELATED,ESTABLISHED ufw-user-output all -- 0.0.0.0/0 0.0.0.0/0 RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-not-local (1 references) target prot opt source destination RETURN all -- 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type LOCAL RETURN all -- 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type MULTICAST RETURN all -- 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type BROADCAST LOG all -- 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix `[UFW BLOCK NOT-TO-ME]: ' DROP all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-user-forward (1 references) target prot opt source destination RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-user-input (1 references) target prot opt source destination ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:80 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:22 ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:22 RETURN all -- 0.0.0.0/0 0.0.0.0/0 Chain ufw-user-output (1 references) target prot opt source destination RETURN all -- 0.0.0.0/0 0.0.0.0/0

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• Why does my Spring Controller direct me to the wrong page?

  - by kc2001

  I am writing my first Spring 3.0.5 MVC app and am confused about why my controller mappings aren't doing what I expect. I have a VerifyPasswordController that is called after a user tries to log in by entering his name and password. // Called upon clicking "submit" from /login @RequestMapping(value = "/verifyPassword", method = RequestMethod.POST) @ModelAttribute("user") public String verifyPassword(User user, BindingResult result) { String email = user.getEmail(); String nextPage = CHOOSE_OPERATION_PAGE; // success case if (result.hasErrors()) { nextPage = LOGIN_PAGE; } else if (!passwordMatches(email, user.getPassword())) { nextPage = LOGIN_FAILURE_PAGE; } else { // success } return nextPage; } I can verify in the debugger that this method is being called, but afterwards, the verifyPassword page is displayed rather than the chooseOperation page. The console output of WebLogic seems to show that my mapping are correct: INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation] onto handler 'chooseOperationController' INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation.*] onto handler 'chooseOperationController' INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation/] onto handler 'chooseOperationController' Here is the ChooseOperationController: @Controller @SessionAttributes("leaveRequestForm") public class ChooseOperationController implements PageIfc, AttributeIfc { @RequestMapping(value = "/chooseOperation") @ModelAttribute("leaveRequestForm") public LeaveRequest setUpLeaveRequestForm( @RequestParam(NAME_ATTRIBUTE) String name) { LeaveRequest form = populateFormFromDatabase(name); return form; } // helper methods omited } I welcome any advice, particularly "generic" techniques for debugging such mapping problems. BTW, I've also tried to "redirect" to the desired page, but got the same result. servlet-context.xml: <?xml version="1.0" encoding="UTF-8"?> <beans:beans xmlns="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure --> <!-- Enables the Spring MVC @Controller programming model --> <annotation-driven /> <!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory --> <resources mapping="/resources/**" location="/resources/" /> <!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory --> <beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <beans:property name="prefix" value="/WEB-INF/views/" /> <beans:property name="suffix" value=".jsp" /> </beans:bean> <context:component-scan base-package="com.engilitycorp.leavetracker" /> <beans:bean id="leaveRequestForm" class="com.engilitycorp.leavetracker.model.LeaveRequest" /> </beans:beans> The constants: String LOGIN_FAILURE_PAGE = "loginFailure"; String LOGIN_PAGE = "login"; String CHOOSE_OPERATION_PAGE = "chooseOperation";

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• Myself throwing NullReferenceException... needs help

  - by Amit Ranjan

  I know it might be a weird question and its Title too, but i need your help. I am a .net dev , working on platform for the last 1.5 years. I am bit confused on the term usually we say " A Good Programmer ". I dont know ,what are the qualities of a good programmer ? Is the guy who writes a bug free code? or Can develop applications solely? or blah blah blah...lots of points. I dont know... But as far i am concerned , I know I am not a good programmer, still in learning phase an needs a lot to learn in coming days. So you guys are requested to please help me with this two problems of mine My first problem is regarding the proper Error Handling, which is a most debatable aspect of programming. We all know we use ` try { } catch { } finally { } ` in our code to manage exception. But even if I use try { } catch(exception ex) { throw ex } finally { } , different guys have different views. I still dont know the good way to handle errors. I can write code, use try-catch but still i feel I lacks something. When I saw the codes generated by .net fx tools even they uses throw ex or `throw new Exception("this is my exception")`.. I am just wondering what will be the best way to achieve the above. All means the same thing but why we avoid something. If it has some demerits then it must be made obselete.Anyways I still dont have one [how to handle errors efficiently?]. I generally follow the try-catch(execoption ex){throw ex}, and usually got stucked in debates with leads why you follow this why not that... 2.Converting your entire code blocks in modules using Design patterns of some OOPs concepts. How do you guys decide what architeture or pattern will be the best for my upcoming application based on its working, flow etc. I need to know what you guys can see that I can't. Since I know , I dont have that much experience but I can say, with my experience that experience doesnot comes either from degree/certificates or success you made instead it cames from failures you faced or got stucking situations. Pleas help me out.

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• Array Sorting Question for News System

  - by lemonpole

  Hello all. I'm currently stuck trying to figure out how to sort my array files. I have a simple news posting system that stores the content in seperate .dat files and then stores them in an array. I numbered the files so that my array can sort them from lowest number to greatest; however, I have run into a small problem. To begin here is some more information on my system so that you can understand it better. The function that gathers my files is: function getNewsList() { $fileList = array(); // Open the actual directory if($handle = opendir(ABSPATH . ADMIN . "data")) { // Read all file from the actual directory while($file = readdir($handle)) { if(!is_dir($file)) { $fileList[] = $file; } } } // Return the array. return $fileList; } On a seperate file is the programming that processes the news post. I didn't post that code for simplicity's sake but I will explain how the files are named. The files are numbered and the part of the post's title is used... for the numbering I get a count of the array and add "1" as an offset. I get the title of the post, encode it to make it file-name-friendly and limit the amount of text so by the end of it all I end up with: // Make the variable that names the file that will contain // the post. $filename = "00{$newnumrows}_{$snipEncode}"; When running print_r on the above function I get: Array ( [0] => 0010_Mira_mi_Soledad.dat [1] => 0011_WOah.dat [2] => 0012_Sinep.dat [3] => 0013_Living_in_Warfa.dat [4] => 0014_Hello.dat [5] => 001_AS.dat [6] => 002_ASASA.dat [7] => 003_SSASAS.dat ... [13] => 009_ASADADASADAFDAF.dat ) And this is how my content is displayed. For some reason according to the array sorting 0010 comes before 001...? Is there a way I can get my array to sort 001 before 0010?

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• Nginx + PHP-FPM on Centos 6.5 gives me 502 Bad Gateway (fpm error: unable to read what child say: Bad file descriptor)

  - by Latheesan Kanes

  I am setting up a standard LEMP stack. My current setup is giving me the following error: 502 Bad Gateway This is what is currently installed on my server: Here's the configurations I've created/updated so far, can some one take a look at the following and see where the error might be? I've already checked my logs, there's nothing in there (http://i.imgur.com/iRq3ksb.png). And I saw the following in /var/log/php-fpm/error.log file. sidenote: both the nginx and php-fpm has been configured to run under a local account called www-data and the following folders exits on the server nginx.conf global nginx configuration user www-data; worker_processes 6; worker_rlimit_nofile 100000; error_log /var/log/nginx/error.log crit; pid /var/run/nginx.pid; events { worker_connections 2048; use epoll; multi_accept on; } http { include /etc/nginx/mime.types; default_type application/octet-stream; # cache informations about FDs, frequently accessed files can boost performance open_file_cache max=200000 inactive=20s; open_file_cache_valid 30s; open_file_cache_min_uses 2; open_file_cache_errors on; # to boost IO on HDD we can disable access logs access_log off; # copies data between one FD and other from within the kernel # faster then read() + write() sendfile on; # send headers in one peace, its better then sending them one by one tcp_nopush on; # don't buffer data sent, good for small data bursts in real time tcp_nodelay on; # server will close connection after this time keepalive_timeout 60; # number of requests client can make over keep-alive -- for testing keepalive_requests 100000; # allow the server to close connection on non responding client, this will free up memory reset_timedout_connection on; # request timed out -- default 60 client_body_timeout 60; # if client stop responding, free up memory -- default 60 send_timeout 60; # reduce the data that needs to be sent over network gzip on; gzip_min_length 10240; gzip_proxied expired no-cache no-store private auth; gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml; gzip_disable "MSIE [1-6]\."; # Load vHosts include /etc/nginx/conf.d/*.conf; } conf.d/www.domain.com.conf my vhost entry ## Nginx php-fpm Upstream upstream wwwdomaincom { server unix:/var/run/php-fcgi-www-data.sock; } ## Global Config client_max_body_size 10M; server_names_hash_bucket_size 64; ## Web Server Config server { ## Server Info listen 80; server_name domain.com *.domain.com; root /home/www-data/public_html; index index.html index.php; ## Error log error_log /home/www-data/logs/nginx-errors.log; ## DocumentRoot setup location / { try_files $uri $uri/ @handler; expires 30d; } ## These locations would be hidden by .htaccess normally #location /app/ { deny all; } ## Disable .htaccess and other hidden files location /. { return 404; } ## Magento uses a common front handler location @handler { rewrite / /index.php; } ## Forward paths like /js/index.php/x.js to relevant handler location ~ .php/ { rewrite ^(.*.php)/ $1 last; } ## Execute PHP scripts location ~ \.php$ { try_files $uri =404; expires off; fastcgi_read_timeout 900; fastcgi_pass wwwdomaincom; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } ## GZip Compression gzip on; gzip_comp_level 8; gzip_min_length 1000; gzip_proxied any; gzip_types text/plain application/xml text/css text/js application/x-javascript; } /etc/php-fpm.d/www-data.conf my php-fpm pool config ## Nginx php-fpm Upstream upstream wwwdomaincom { server unix:/var/run/php-fcgi-www-data.sock; } ## Global Config client_max_body_size 10M; server_names_hash_bucket_size 64; ## Web Server Config server { ## Server Info listen 80; server_name domain.com *.domain.com; root /home/www-data/public_html; index index.html index.php; ## Error log error_log /home/www-data/logs/nginx-errors.log; ## DocumentRoot setup location / { try_files $uri $uri/ @handler; expires 30d; } ## These locations would be hidden by .htaccess normally #location /app/ { deny all; } ## Disable .htaccess and other hidden files location /. { return 404; } ## Magento uses a common front handler location @handler { rewrite / /index.php; } ## Forward paths like /js/index.php/x.js to relevant handler location ~ .php/ { rewrite ^(.*.php)/ $1 last; } ## Execute PHP scripts location ~ \.php$ { try_files $uri =404; expires off; fastcgi_read_timeout 900; fastcgi_pass wwwdomaincom; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } ## GZip Compression gzip on; gzip_comp_level 8; gzip_min_length 1000; gzip_proxied any; gzip_types text/plain application/xml text/css text/js application/x-javascript; } I've got a file in /home/www-data/public_html/index.php with the code <?php phpinfo(); ?> (file uploaded as user www-data).

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• My mental block - struggling to learn Objective C

  - by iqessar

  Hello people, this would be my first question after signing up! Anyway heres my question, I did Java at university and I was always told I am a good programmer. However I never pursued it as a career - I went into support and management instead. Im pretty much bored with my job, I have therefore started to learn Objective C so that I can develop apps for the iphone. I am currently watching several different Videos / Books. My problem is that when I go through the Apple documentation, although I understand most of it, sometimes I stumble. I believe that because you/we have the Apple documentation (i.e. Framework references) , everything should be clear, and therefore you should have no need to refer to a book or video (in order to learn how to use a particular class). But I alway do refer to a book and video and subsequently feel guilty as I believe the framework reference should be enough. (I therefore feel I am not up to being a programmer) I also believe that you shouldn't need example code in order to learn how to use a particular class because Apple provides documentation for each class, but AGAIN I find my self googling example code and I find my answer like that - again I feel guilty for doing this. Am I right in saying that Apple documentation is simply not clear? and that its ok to refer to a video/book or google? or forums for that matter? I have proffesional programmers who tell me that I am worrying too much and that I should get on with it and use all the resources that I have. I just cant seem to get round this mental block that I have in my head. When I start a programming project I am able to use the excellent search skills that I have to find the code I need, copy and paste it (yes I do understand it) BUT then I feel guilty telling myself that why didn't you think up the code yourself???? Therefore your not a real programmer, your just good at googling. Currently I am going through 20+ books so that I can learn most of the frameworks, syntax etc to develop iphone apps. I believe if I do this, then when I think of a project I can make it quickly. Should I read a few books, like 2-3 and then just start a project /app , and if I get stuck just google it and get the code I need? Can anybody please answer my questions?

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• Java: Combination of recursive loops which has different FOR loop inside; Output: FOR loops indexes

  - by vvinjj

  currently recursion is fresh & difficult topic for me, however I need to use it in one of my algorithms. Here is the challenge: I need a method where I specify number of recursions (number of nested FOR loops) and number of iterations for each FOR loop. The result should show me, something simmilar to counter, however each column of counter is limited to specific number. ArrayList<Integer> specs= new ArrayList<Integer>(); specs.add(5); //for(int i=0 to 5; i++) specs.add(7); specs.add(9); specs.add(2); specs.add(8); specs.add(9); public void recursion(ArrayList<Integer> specs){ //number of nested loops will be equal to: specs.size(); //each item in specs, specifies the For loop max count e.g: //First outside loop will be: for(int i=0; i< specs.get(0); i++) //Second loop inside will be: for(int i=0; i< specs.get(1); i++) //... } The the results will be similar to outputs of this manual, nested loop: int[] i; i = new int[7]; for( i[6]=0; i[6]<5; i[6]++){ for( i[5]=0; i[5]<7; i[5]++){ for(i[4] =0; i[4]<9; i[4]++){ for(i[3] =0; i[3]<2; i[3]++){ for(i[2] =0; i[2]<8; i[2]++){ for(i[1] =0; i[1]<9; i[1]++){ //... System.out.println(i[1]+" "+i[2]+" "+i[3]+" "+i[4]+" "+i[5]+" "+i[6]); } } } } } } I already, killed 3 days on this, and still no results, was searching it in internet, however the examples are too different. Therefore, posting the programming question in internet first time in my life. Thank you in advance, you are free to change the code efficiency, I just need the same results.

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• problem with Using SAX parser

  - by moustafa

  Hi guys i have this small class task that im having trouble with. I need to create a PHP file using SAX to generate the display shown below from an XML file. Im not sure how to Use | to represent its level, where the root element orders is at level zero. This is what the result should look like when i parse it through a SAX parser http://img13.imageshack.us/img13/6950/75914446.jpg This is the XML source code from which i need to generate the display: <orders> <order> <count>37</count> <price>49.99</price> <book> <isbn>0130897930</isbn> <title>Core Web Programming Second Edition</title> <authors> <count>2</count> <author>Marty Hall</author> <author>Larry Brown</author> </authors> </book> </order> <order> <count>1</count> <price>9.95</price> <yacht> <manufacturer>Luxury Yachts, Inc.</manufacturer> <model>M-1</model> <standardFeatures oars="plastic" lifeVests="none">false</standardFeatures> </yacht> </order> <order> <count>3</count> <price>22.22</price> <book> <isbn>B000059Z4H</isbn> <title>Harry Potter and the Order of the Phoenix</title> <authors> <count>1</count> <author>J.K. Rowling</author> </authors> </book> </order>

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• printf anomaly after "fork()"

  - by pechenie

  OS: Linux, Language: pure C I'm moving forward in learning C progpramming in general, and C programming under UNIX in a special case :D So, I detected a strange (as for me) behaviour of the printf() function after using a fork() call. Let's take a look at simple test program: #include <stdio.h> #include <system.h> int main() { int pid; printf( "Hello, my pid is %d", getpid() ); pid = fork(); if( pid == 0 ) { printf( "\nI was forked! :D" ); sleep( 3 ); } else { waitpid( pid, NULL, 0 ); printf( "\n%d was forked!", pid ); } return 0; } In this case the output looks like: Hello, my pid is 1111 I was forked! :DHello, my pid is 1111 2222 was forked! Why the second "Hello" string occured in the child's output? Yes, it is exactly what the parent printed on it's start, with the parent's pid. But! If we place '\n' character in the end of each string we got the expected output: #include <stdio.h> #include <system.h> int main() { int pid; printf( "Hello, my pid is %d\n", getpid() ); // SIC!! pid = fork(); if( pid == 0 ) { printf( "I was forked! :D" ); //removed the '\n', no matter sleep( 3 ); } else { waitpid( pid, NULL, 0 ); printf( "\n%d was forked!", pid ); } return 0; } And the output looks like: Hello, my pid is 1111 I was forked! :D 2222 was forked! Why does it happen? Is it ... ummm ... correct behaviour? Or it's a kind of the 'bug'?

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