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  • WCF Endpoints & Binding Configuration Issues

    - by CodeAbundance
    I am running into a very strange issue here folks. For simplicity I created a project for the sole purpose of testing the issue outside the framework of a larger application and still encountered what is either a bug in WCF within Visual Studio 2010 or something related to my WCF newbie skill set : ) Here is the issue: I have a WCF endpoint I created running inside of an MVC3 project called "SimpleMethod". The method runs inside of a .svc file on the root of the application and it returns a bool. Using the "WCF Service Configuration Editor" I have added the endpoint to my Web.Config along with a called "LargeImageBinding". Here is the service: [OperationContract] public bool SimpleMethod() { return true; } And the Web.Config generated by the Config Tool: <system.serviceModel> <bindings> <wsHttpBinding> <binding name="LargeImageBinding" closeTimeout="00:10:00" /> </wsHttpBinding> </bindings> <services> <service name="WCFEndpoints.ServiceTestOne"> <endpoint address="/ServiceTestOne.svc" binding="wsHttpBinding" bindingConfiguration="LargeImageBinding" contract="WCFEndpoints.IServiceTestOne" /> </service> </services> <behaviors> <serviceBehaviors> <behavior name=""> <serviceMetadata httpGetEnabled="true" /> <serviceDebug includeExceptionDetailInFaults="false" /> </behavior> </serviceBehaviors> </behaviors> <serviceHostingEnvironment multipleSiteBindingsEnabled="true" /> The service renders fine and you can see the endpoint when you navigate to: http://localhost:57364/ServiceTestOne.svc - Now the issue occurs when I create a separate project to consume the service. I add a service reference to a running instance of the above project, point it to: http://localhost:57364/ServiceTestOne.svc Here is the weird part. The service automatically generates just fine but In the Web.Config the endpoint that is generated looks like this: <client> <endpoint address="http://localhost:57364/ServiceTestOne.svc/ServiceTestOne.svc" binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IServiceTestOne" contract="ServiceTestOne.IServiceTestOne" name="WSHttpBinding_IServiceTestOne"> As you can see it lists the "ServiceTestOne.svc" portion of the address twice! When I make a call to the the service I get the following error: The remote server returned an error: (404) Not Found. I tried removing the extra "/ServiceTestOne.svc" at the end of the endpoint address in the above config, and I get the same exact error. Now what DOES work is if I go back to the WCF application and remove the custom endpoint and binding references in the Web.Config (everything in the "services" and "bindings" tags) then go back to the consumer application, update the reference to the service and make the call to SimpleMethod()....BOOM works like a charm and I get back a bool set to true. The thing is, I need to make custom binding configurations in order to allow for access to the service outside of the defaults, and from what I can tell, any attempt to create custom bindings makes the endpoints seem to run fine, but fail when an actual method call is made. Can anyone see any flaw in how I am putting this together? Thank you for your time - I have been running in circles with this for about a week!

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  • Separate specific #ifdef branches

    - by detly
    In short: I want to generate two different source trees from the current one, based only on one preprocessor macro being defined and another being undefined, with no other changes to the source. If you are interested, here is my story... In the beginning, my code was clean. Then we made a new product, and yea, it was better. But the code saw only the same peripheral devices, so we could keep the same code. Well, almost. There was one little condition that needed to be changed, so I added: #if defined(PRODUCT_A) condition = checkCat(); #elif defined(PRODUCT_B) condition = checkCat() && checkHat(); #endif ...to one and only one source file. In the general all-source-files-include-this header file, I had: #if !(defined(PRODUCT_A)||defined(PRODUCT_B)) #error "Don't make me replace you with a small shell script. RTFM." #endif ...so that people couldn't compile it unless they explicitly defined a product type. All was well. Oh... except that modifications were made, components changed, and since the new hardware worked better we could significantly re-write the control systems. Now when I look upon the face of the code, there are more than 60 separate areas delineated by either: #ifdef PRODUCT_A ... #else ... #endif ...or the same, but for PRODUCT_B. Or even: #if defined(PRODUCT_A) ... #elif defined(PRODUCT_B) ... #endif And of course, sometimes sanity took a longer holiday and: #ifdef PRODUCT_A ... #endif #ifdef PRODUCT_B ... #endif These conditions wrap anywhere from one to two hundred lines (you'd think that the last one could be done by switching header files, but the function names need to be the same). This is insane. I would be better off maintaining two separate product-based branches in the source repo and porting any common changes. I realise this now. Is there something that can generate the two different source trees I need, based only on PRODUCT_A being defined and PRODUCT_B being undefined (and vice-versa), without touching anything else (ie. no header inclusion, no macro expansion, etc)?

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  • Java List to Excel Columns

    - by Nitin
    Correct me where I'm going wrong. I'm have written a program in Java which will get list of files from two different directories and make two (Java list) with the file names. I want to transfer the both the list (downloaded files list and Uploaded files list) to an excel. What the result i'm getting is those list are transferred row wise. I want them in column wise. Given below is the code: public class F { static List<String> downloadList = new ArrayList<>(); static List<String> dispatchList = new ArrayList<>(); public static class FileVisitor extends SimpleFileVisitor<Path> { @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { String name = file.toRealPath().getFileName().toString(); if (name.endsWith(".pdf") || name.endsWith(".zip")) { downloadList.add(name); } if (name.endsWith(".xml")) { dispatchList.add(name); } return FileVisitResult.CONTINUE; } } public static void main(String[] args) throws IOException { try { Path downloadPath = Paths.get("E:\\report\\02_Download\\10252013"); Path dispatchPath = Paths.get("E:\\report\\01_Dispatch\\10252013"); FileVisitor visitor = new FileVisitor(); Files.walkFileTree(downloadPath, visitor); Files.walkFileTree(downloadPath, EnumSet.of(FileVisitOption.FOLLOW_LINKS), 1, visitor); Files.walkFileTree(dispatchPath, visitor); Files.walkFileTree(dispatchPath, EnumSet.of(FileVisitOption.FOLLOW_LINKS), 1, visitor); System.out.println("Download File List" + downloadList); System.out.println("Dispatch File List" + dispatchList); F f = new F(); f.UpDown(downloadList, dispatchList); } catch (Exception ex) { Logger.getLogger(F.class.getName()).log(Level.SEVERE, null, ex); } } int rownum = 0; int colnum = 0; HSSFSheet firstSheet; Collection<File> files; HSSFWorkbook workbook; File exactFile; { workbook = new HSSFWorkbook(); firstSheet = workbook.createSheet("10252013"); Row headerRow = firstSheet.createRow(rownum); headerRow.setHeightInPoints(40); } public void UpDown(List<String> download, List<String> upload) throws Exception { List<String> headerRow = new ArrayList<>(); headerRow.add("Downloaded"); headerRow.add("Uploaded"); List<List> recordToAdd = new ArrayList<>(); recordToAdd.add(headerRow); recordToAdd.add(download); recordToAdd.add(upload); F f = new F(); f.CreateExcelFile(recordToAdd); f.createExcelFile(); } void createExcelFile() { FileOutputStream fos = null; try { fos = new FileOutputStream(new File("E:\\report\\Download&Upload.xls")); HSSFCellStyle hsfstyle = workbook.createCellStyle(); hsfstyle.setBorderBottom((short) 1); hsfstyle.setFillBackgroundColor((short) 245); workbook.write(fos); } catch (Exception e) { } } public void CreateExcelFile(List<List> l1) throws Exception { try { for (int j = 0; j < l1.size(); j++) { Row row = firstSheet.createRow(rownum); List<String> l2 = l1.get(j); for (int k = 0; k < l2.size(); k++) { Cell cell = row.createCell(k); cell.setCellValue(l2.get(k)); } rownum++; } } catch (Exception e) { } finally { } } } (The purpose is to verify the files Downloaded and Uploaded for the given date) Thanks.

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  • Internet Explorer background-color hover problem

    - by danilo
    I have a strange Problem with table formating using IE 7. My table looks like this: In IE, when using border-collapse, the borders don't get displayed correctly. That's why I used this fix: .table-vmlist td { border-top: 1px solid black; } td.col-vm-status, tr.row-details td { border-left: 1px solid black; } td.col-vm-rdp, tr.row-details td { border-right: 1px solid black; } .table-vmlist { border-bottom: 1px solid black;} When hovering over the row, it gets highlighted with CSS: .table-vmlist tr.row-vm { background-color: #A4C3EF; } .table-vmlist tr.row-vm:hover { background-color: #91BAEF; } Now, in IE 7, when moving the mouse from the top to the bottom of the list, every row gets highlighted correctly and no problems happen. But if I move my mouse pointer from the bottom of the list to the top, every second row seems to loose the border. Can someone explain what the problem is, and how to solve it? This is my markup: <tr class="row-vm"> <td class="col-vm-status status-1"><img title="Host Down" alt="Down" src="/Technik/vm-management/img/hoststatus_1.png"></td> <td class="col-vm-name">V1-VM-1</td> <td class="col-vm-stati"> <img title="Ping" alt="Ping status" src="/Technik/vm-management/img/servicestatus_3.png"> <img title="CPU" alt="CPU status" src="/Technik/vm-management/img/servicestatus_3.png"> <img title="RAM" alt="RAM status" src="/Technik/vm-management/img/servicestatus_3.png"> <img title="C:\ Diskspace" alt="Disk space status" src="/Technik/vm-management/img/servicestatus_3.png"> </td> <td class="col-vm-owner">kus</td> <td class="col-vm-purpose">Citrix Testserver</td> <td class="col-vm-ip">-</td> <td class="col-vm-uptime">-</td> <td class="col-vm-rdp">&nbsp;</td> </tr> And the CSS: /* VM-Tabelle formatieren */ .table-vmlist { border-collapse: collapse; } .table-vmlist tr { border: 1px solid black; } .table-vmlist tr.row-header { border: none; } .table-vmlist tr.row-vm { background-color: #A4C3EF; } .table-vmlist tr.row-vm:hover { background-color: #91BAEF; } .table-vmlist th { text-align: left; } .table-vmlist td { } .table-vmlist th, table td { padding: 2px 0px; } /* Spaltenbreite der VM-Tabelle festlegen */ .table-vmlist #col-status { width: 25px; } .table-vmlist #col-stati { width: 90px; } .table-vmlist #col-owner { width: 90px; } .table-vmlist #col-ip { width: 100px; } .table-vmlist #col-uptime { width: 70px; } .table-vmlist #col-rdp { width: 25px; } .table-vmlist tr.row-details td { padding: 0px 10px; } /* Kein Rahmen um verlinkte Bilder */ a img { border-width: 0px; } /* Für Einschaltknopf Hand-Cursor anstatt normalen Pfeil anzeigen */ td.status-1 img { cursor: pointer; } img.ajax-loader { margin-left: 2px; } IE fix: .table-vmlist td { border-top: 1px solid black; } td.col-vm-status, tr.row-details td { border-left: 1px solid black; } td.col-vm-rdp, tr.row-details td { border-right: 1px solid black; } .table-vmlist { border-bottom: 1px solid black;}

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  • iPhone Debugger Message -- Weird

    - by Bill Shiff
    Hello, I have an iPhone app that I've been working on and have recently upgraded my version of XCode. Since the upgrade, I can build and debug in the iPhone Simulator just fine, but when I try to debug on an attached device I get the following messages: From Xcode4: GNU gdb 6.3.50-20050815 (Apple version gdb-1510) (Fri Oct 22 04:12:10 UTC 2010) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys001 sharedlibrary apply-load-rules all warning: Unable to read symbols from "dyld" (prefix __dyld_) (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/MessageUI.framework/MessageUI (file not found). warning: Unable to read symbols from "MessageUI" (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/MapKit.framework/MapKit (file not found). warning: Unable to read symbols from "MapKit" (not yet mapped into memory). warning: Unable to read symbols from "Foundation" (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/UIKit.framework/UIKit (file not found). warning: Unable to read symbols from "UIKit" (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/CoreGraphics.framework/CoreGraphics (file not found). warning: Unable to read symbols from "CoreGraphics" (not yet mapped into memory). warning: Unable to read symbols from "CoreData" (not yet mapped into memory). warning: Unable to read symbols from "QuartzCore" (not yet mapped into memory). warning: Unable to read symbols from "libgcc_s.1.dylib" (not yet mapped into memory). warning: Unable to read symbols from "libSystem.B.dylib" (not yet mapped into memory). warning: Unable to read symbols from "libobjc.A.dylib" (not yet mapped into memory). warning: Unable to read symbols from "CoreFoundation" (not yet mapped into memory). target remote-mobile /tmp/.XcodeGDBRemote-3836-28 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none [Switching to thread 11523] [Switching to thread 11523] gdb stack crawl at point of internal error: 0 gdb-arm-apple-darwin 0x0013216e internal_vproblem + 316

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  • approximating log10[x^k0 + k1]

    - by Yale Zhang
    Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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  • Calculating rotation and translation matrices between two odometry positions for monocular linear triangulation

    - by user1298891
    Recently I've been trying to implement a system to identify and triangulate the 3D position of an object in a robotic system. The general outline of the process goes as follows: Identify the object using SURF matching, from a set of "training" images to the actual live feed from the camera Move/rotate the robot a certain amount Identify the object using SURF again in this new view Now I have: a set of corresponding 2D points (same object from the two different views), two odometry locations (position + orientation), and camera intrinsics (focal length, principal point, etc.) since it's been calibrated beforehand, so I should be able to create the 2 projection matrices and triangulate using a basic linear triangulation method as in Hartley & Zissermann's book Multiple View Geometry, pg. 312. Solve the AX = 0 equation for each of the corresponding 2D points, then take the average In practice, the triangulation only works when there's almost no change in rotation; if the robot even rotates a slight bit while moving (due to e.g. wheel slippage) then the estimate is way off. This also applies for simulation. Since I can only post two hyperlinks, here's a link to a page with images from the simulation (on the map, the red square is simulated robot position and orientation, and the yellow square is estimated position of the object using linear triangulation.) So you can see that the estimate is thrown way off even by a little rotation, as in Position 2 on that page (that was 15 degrees; if I rotate it any more then the estimate is completely off the map), even in a simulated environment where a perfect calibration matrix is known. In a real environment when I actually move around with the robot, it's worse. There aren't any problems with obtaining point correspondences, nor with actually solving the AX = 0 equation once I compute the A matrix, so I figure it probably has to do with how I'm setting up the two camera projection matrices, specifically how I'm calculating the translation and rotation matrices from the position/orientation info I have relative to the world frame. How I'm doing that right now is: Rotation matrix is composed by creating a 1x3 matrix [0, (change in orientation angle), 0] and then converting that to a 3x3 one using OpenCV's Rodrigues function Translation matrix is composed by rotating the two points (start angle) degrees and then subtracting the final position from the initial position, in order to get the robot's straight and lateral movement relative to its starting orientation Which results in the first projection matrix being K [I | 0] and the second being K [R | T], with R and T calculated as described above. Is there anything I'm doing really wrong here? Or could it possibly be some other problem? Any help would be greatly appreciated.

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  • Need some help accessing password string / Debugging

    - by Josh Lake
    I'm doing this code for the sole purpose in trying out how to get the password field masked. Any suggestions on where to go next? #include <iostream> #include <cmath> #include <stdio.h> #include <cstring> #include <conio.h> using namespace std; inline void keep_window_open() { char ch; cin>>ch; } int main() { cout << "Welcome to the Classified Network, DOD842349729961971\n"; cout << "Username: \n"; string admin = "gardinerca"; string root_password = "password1"; string full_name = "User Name"; string name; cin >> name; if (name == admin) { printf("Password: "); char password[10]; int i; for (i = 0; i <= 10; i++) { int c = getch(); if (c == '\n' || c == EOF) break; password[i] = c; printf("*"); } password[i] = '\0'; if (strcmp(password, root_password) == 0) { system("CLS"); cout << "Welcome " << full_name << " to the Classified Network\n"; cout << "Would you like to play a game? (Y or N)\n"; string play_game; cin >> play_game; if (play_game == "Y") { cout << "How many balls can you stick in your mouth?\n"; int balls; cin >> balls; string one; string two; one = "One Ball"; two = "Two Ball's"; if (balls == 1) cout << "You can honestly stick " << one << " in your mouth?"; } else { cout << "You have selected the No Option. Thats fine...we don't want to play with you either\n"; } } else { cout << "Invaild Password. Please contact system administrator.\n"; cin.clear(); system ("PAUSE"); } else { cout << "No Username found. Please contact system administrator.\n"; cin.clear(); system ("PAUSE"); } return 0; }

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  • "C variable type sizes are machine dependent." Is it really true? signed & unsigned numbers ;

    - by claws
    Hello, I've been told that C types are machine dependent. Today I wanted to verify it. void legacyTypes() { /* character types */ char k_char = 'a'; //Signedness --> signed & unsigned signed char k_char_s = 'a'; unsigned char k_char_u = 'a'; /* integer types */ int k_int = 1; /* Same as "signed int" */ //Signedness --> signed & unsigned signed int k_int_s = -2; unsigned int k_int_u = 3; //Size --> short, _____, long, long long short int k_s_int = 4; long int k_l_int = 5; long long int k_ll_int = 6; /* real number types */ float k_float = 7; double k_double = 8; } I compiled it on a 32-Bit machine using minGW C compiler _legacyTypes: pushl %ebp movl %esp, %ebp subl $48, %esp movb $97, -1(%ebp) # char movb $97, -2(%ebp) # signed char movb $97, -3(%ebp) # unsigned char movl $1, -8(%ebp) # int movl $-2, -12(%ebp)# signed int movl $3, -16(%ebp) # unsigned int movw $4, -18(%ebp) # short int movl $5, -24(%ebp) # long int movl $6, -32(%ebp) # long long int movl $0, -28(%ebp) movl $0x40e00000, %eax movl %eax, -36(%ebp) fldl LC2 fstpl -48(%ebp) leave ret I compiled the same code on 64-Bit processor (Intel Core 2 Duo) on GCC (linux) legacyTypes: .LFB2: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 movq %rsp, %rbp .cfi_offset 6, -16 .cfi_def_cfa_register 6 movb $97, -1(%rbp) # char movb $97, -2(%rbp) # signed char movb $97, -3(%rbp) # unsigned char movl $1, -12(%rbp) # int movl $-2, -16(%rbp)# signed int movl $3, -20(%rbp) # unsigned int movw $4, -6(%rbp) # short int movq $5, -32(%rbp) # long int movq $6, -40(%rbp) # long long int movl $0x40e00000, %eax movl %eax, -24(%rbp) movabsq $4620693217682128896, %rax movq %rax, -48(%rbp) leave ret Observations char, signed char, unsigned char, int, unsigned int, signed int, short int, unsigned short int, signed short int all occupy same no. of bytes on both 32-Bit & 64-Bit Processor. The only change is in long int & long long int both of these occupy 32-bit on 32-bit machine & 64-bit on 64-bit machine. And also the pointers, which take 32-bit on 32-bit CPU & 64-bit on 64-bit CPU. Questions: I cannot say, what the books say is wrong. But I'm missing something here. What exactly does "Variable types are machine dependent mean?" As you can see, There is no difference between instructions for unsigned & signed numbers. Then how come the range of numbers that can be addressed using both is different? I was reading http://stackoverflow.com/questions/2511246/how-to-maintain-fixed-size-of-c-variable-types-over-different-machines I didn't get the purpose of the question or their answers. What maintaining fixed size? They all are the same. I didn't understand how those answers are going to ensure the same size.

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  • Problem with evaluating XPath expression in Java

    - by JSteve
    Can somebody help me find the mistake I am doing in evaluating following XPath expression? I want to get all "DataTable" nodes under the node "Model" in my xml through XPath. Here is my XML doc: <?xml version="1.0" encoding="UTF-8"?> <Root> <Application> <Model> <DataSet name="ds" primaryTable="Members" openRows="1"> <DataTable name="Members" openFor="write"> <DataColumn name="id" type="String" mandatory="true" primaryKey="true" valueBy="user"/> <DataColumn name="name" type="String" mandatory="true" valueBy="user"/> <DataColumn name="address" type="String" mandatory="false" valueBy="user"/> <DataColumn name="city" type="String" mandatory="false" valueBy="user"/> <DataColumn name="country" type="String" mandatory="false" valueBy="user"/> </DataTable> </DataSet> </Model> <View> <Composite> <Grid> <Label value="ID:" row="0" column="0" /> <Label value="Name:" row="1" column="0" /> <Label value="Address:" row="2" column="0" /> <Label value="City:" row="3" column="0" /> <Label value="Country:" row="4" column="0" /> <TextField name="txtId" row="0" column="1" /> <TextField name="txtName" row="1" column="1" /> <TextField name="txtAddress" row="2" column="1" /> <TextField name="txtCity" row="3" column="1" /> <TextField name="txtCountry" row="4" column="1" /> </Grid> </Composite> </View> </Application> </Root> Here the Java code to extract required node list: try { DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance(); domFactory.setNamespaceAware(true); domFactory.setIgnoringComments(true); domFactory.setIgnoringElementContentWhitespace(true); DocumentBuilder builder = domFactory.newDocumentBuilder(); Document dDoc = builder.parse("D:\TEST\myFile.xml"); XPath xpath = XPathFactory.newInstance().newXPath(); NodeList nl = (NodeList) xpath.evaluate("//Model//DataTable", dDoc, XPathConstants.NODESET); System.out.println(nl.getLength()); }catch (Exception ex) { System.out.println(ex.getMessage()); } There is no problem in loading and parsing xml file and I can see correct nodes in dDoc. Problem is with xpath that returns nothing on evaluating my expression. I tried many other expressions for testing purpose but every time resulting NodeList "nl" does not have any item

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  • A NSMutableArray is destroying my life!

    - by camilo
    EDITED to show the relevant part of the code Hi. There's a strange problem with an NSMutableArray which I'm just not understanding... Explaining: I have a NSMutableArray, defined as a property (nonatomic, retain), synthesized, and initialized with 29 elements. realSectionNames = [[NSMutableArray alloc] initWithCapacity:29]; After the initialization, I can insert elements as I wish and everything seems to be working fine. While I'm running the application, however, if I insert a new element in the array, I can print the array in the function where I inserted the element, and everything seems ok. However, when I select a row in the table, and I need to read that array, my application crashes. In fact, it cannot even print the array anymore. Is there any "magical and logical trick" everybody should know when using a NSMutableArray that a beginner like myself can be missing? Thanks a lot. I declare my array as realSectionNames = [[NSMutableArray alloc] initWithCapacity:29]; I insert objects in my array with [realSectionNames addObject:[category categoryFirstLetter]]; although I know i can also insert it with [realSectionNames insertObject:[category categoryFirstLetter] atIndex:i]; where the "i" is the first non-occupied position. After the insertion, I reload the data of my tableView. Printing the array before or after reloading the data shows it has the desired information. After that, selecting a row at the table makes the application crash. This realSectionNames is used in several UITableViewDelegate functions, but for the case it doesn't matter. What truly matters is that printing the array in the beginning of the didSelectRowAtIndexPath function crashes everything (and of course, doesn't print anything). I'm pretty sure it's in that line, for printing anything he line before works (example): NSLog(@"Anything"); NSLog(@"%@", realSectionNames); gives the output: 2010-03-24 15:16:04.146 myApplicationExperience[3527:207] Anything [Session started at 2010-03-24 15:16:04 +0000.] GNU gdb 6.3.50-20050815 (Apple version gdb-967) (Tue Jul 14 02:11:58 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-apple-darwin".sharedlibrary apply-load-rules all Attaching to process 3527. Still not understanding what kind of stupidity I've done this time... maybe it's not too late to follow the career of brain surgeon?

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  • map<string, vector<string>> reassignment of vector value

    - by user2950936
    I am trying to write a program that takes lines from an input file, sorts the lines into 'signatures' for the purpose of combining all words that are anagrams of each other. I have to use a map, storing the 'signatures' as the keys and storing all words that match those signatures into a vector of strings. Afterwards I must print all words that are anagrams of each other on the same line. Here is what I have so far: #include <iostream> #include <string> #include <algorithm> #include <map> #include <fstream> using namespace std; string signature(const string&); void printMap(const map<string, vector<string>>&); int main(){ string w1,sig1; vector<string> data; map<string, vector<string>> anagrams; map<string, vector<string>>::iterator it; ifstream myfile; myfile.open("words.txt"); while(getline(myfile, w1)) { sig1=signature(w1); anagrams[sig1]=data.push_back(w1); //to my understanding this should always work, } //either by inserting a new element/key or //by pushing back the new word into the vector<string> data //variable at index sig1, being told that the assignment operator //cannot be used in this way with these data types myfile.close(); printMap(anagrams); return 0; } string signature(const string& w) { string sig; sig=sort(w.begin(), w.end()); return sig; } void printMap(const map& m) { for(string s : m) { for(int i=0;i<m->second.size();i++) cout << m->second.at(); cout << endl; } } The first explanation is working, didn't know it was that simple! However now my print function is giving me: prob2.cc: In function âvoid printMap(const std::map<std::basic_string<char>, std::vector<std::basic_string<char> > >&)â: prob2.cc:43:36: error: cannot bind âstd::basic_ostream<char>::__ostream_type {aka std::basic_ostream<char>}â lvalue to âstd::basic_ostream<char>&&â In file included from /opt/centos/devtoolset-1.1/root/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../include/c++/4.7.2/iostream:40:0, Tried many variations and they always complain about binding void printMap(const map<string, vector<string>> &mymap) { for(auto &c : mymap) cout << c.first << endl << c.second << endl; }

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  • algorithm q: Fuzzy matching of structured data

    - by user86432
    I have a fairly small corpus of structured records sitting in a database. Given a tiny fraction of the information contained in a single record, submitted via a web form (so structured in the same way as the table schema), (let us call it the test record) I need to quickly draw up a list of the records that are the most likely matches for the test record, as well as provide a confidence estimate of how closely the search terms match a record. The primary purpose of this search is to discover whether someone is attempting to input a record that is duplicate to one in the corpus. There is a reasonable chance that the test record will be a dupe, and a reasonable chance the test record will not be a dupe. The records are about 12000 bytes wide and the total count of records is about 150,000. There are 110 columns in the table schema and 95% of searches will be on the top 5% most commonly searched columns. The data is stuff like names, addresses, telephone numbers, and other industry specific numbers. In both the corpus and the test record it is entered by hand and is semistructured within an individual field. You might at first blush say "weight the columns by hand and match word tokens within them", but it's not so easy. I thought so too: if I get a telephone number I thought that would indicate a perfect match. The problem is that there isn't a single field in the form whose token frequency does not vary by orders of magnitude. A telephone number might appear 100 times in the corpus or 1 time in the corpus. The same goes for any other field. This makes weighting at the field level impractical. I need a more fine-grained approach to get decent matching. My initial plan was to create a hash of hashes, top level being the fieldname. Then I would select all of the information from the corpus for a given field, attempt to clean up the data contained in it, and tokenize the sanitized data, hashing the tokens at the second level, with the tokens as keys and frequency as value. I would use the frequency count as a weight: the higher the frequency of a token in the reference corpus, the less weight I attach to that token if it is found in the test record. My first question is for the statisticians in the room: how would I use the frequency as a weight? Is there a precise mathematical relationship between n, the number of records, f(t), the frequency with which a token t appeared in the corpus, the probability o that a record is an original and not a duplicate, and the probability p that the test record is really a record x given the test and x contain the same t in the same field? How about the relationship for multiple token matches across multiple fields? Since I sincerely doubt that there is, is there anything that gets me close but is better than a completely arbitrary hack full of magic factors? Barring that, has anyone got a way to do this? I'm especially keen on other suggestions that do not involve maintaining another table in the database, such as a token frequency lookup table :). This is my first post on StackOverflow, thanks in advance for any replies you may see fit to give.

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  • how to refactor user-permission system?

    - by John
    Sorry for lengthy question. I can't tell if this should be a programming question or a project management question. Any advice will help. I inherited a reasonably large web project (1 year old) from a solo freelancer who architected it then abandoned it. The project was a mess, but I cleaned up what I could, and now the system is more maintainable. I need suggestions on how to extend the user-permission system. As it is now, the database has a t_user table with the column t_user.membership_type. Currently, there are 4 membership types with the following properties: 3 of the membership types are almost functionally the same, except for the different monthly fees each must pay 1 of the membership type is a "fake-user" type which has limited access ( different business logic also applies) With regards to the fake-user type, if you look in the system's business logic files, you will see a lot of hard-coded IF statements that do something like if (fake-user) { // do something } else { // a paid member of type 1,2 or 3 // proceed normally } My client asked me to add 3 more membership types to the system, each of them with unique features to be implemented this month, and substantive "to-be-determined" features next month. My first reaction is that I need to refactor the user-permission system. But it concerns me that I don't have enough information on the "to-be-determined" membership type features for next month. Refactoring the user-permission system will take a substantive amount of time. I don't want to refactor something and throw it out the following month. I get substantive feature requests on a monthly basis that come out of the blue. There is no project road map. I've asked my client to provide me with a roadmap of what they intend to do with the new membership types, but their answer is along the lines of "We just want to do [feature here] this month. We'll think of something new next month." So questions that come to mind are: 1) Is it dangerous for me to refactor the user permission system not knowing what membership type features exist beyond a month from now? 2) Should I refactor the user permission system regardless? Or just continue adding IF statements as needed in all my controller files? Or can you recommend a different approach to user permission systems? Maybe role-based ? 3) Should this project have a road map? For a 1 year old project like mine, how far into the future should this roadmap project? 4) Any general advice on the best way to add 3 new membership types?

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  • Nested Transaction issues within custom Windows Service

    - by pdwetz
    I have a custom Windows Service I recently upgraded to use TransactionScope for nested transactions. It worked fine locally on my old dev machine (XP sp3) and on a test server (Server 2003). However, it fails on my new Windows 7 machine as well as on 2008 Server. It was targeting 2.0 framework; I tried targeting 3.5 instead, but it still fails. The strange part is really in how it fails; no exception is thrown. The service itself merely times out. I added tracing code, and it fails when opening the connection for Database lookup #2 below. I also enabled tracing for System.Transactions; it literally cuts out partway while writing the block for the failed connection. We ran a SQL trace, but only the first lookup shows up. I put in code traces, and it gets to the trace the line before the second lookup, but nothing after. I've had the same experience hitting two different SQL servers (both are SQL 2005 running on Server 2003). The connection string is utilizing a SQL account (not Windows integration). All connections are against the same database in this case, but given the nature of the code it is being escalated to MSDTC. Here's the basic code structure: TransactionOptions options = new TransactionOptions(); options.IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew, options)) { // Database lookup #1 TransactionOptions options = new TransactionOptions(); options.IsolationLevel = Transaction.Current != null ? Transaction.Current.IsolationLevel : System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required, options)) { // Database lookup #2; fails on connection.Open() // Database save (never reached) scope.Complete();<br/> } scope.Complete();<br/> } My local firewall is disabled. The service normally runs using Network Service, but I also tried my user account (same results). The short of it is that I use the same general technique widely in my web applications and haven't had any issues. I pulled out the code and ran it fine within a local Windows Form application. If anyone has any additional debugging ideas (or, even better, solutions) I'd love to hear them.

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  • Multi-threaded Pooled Allocators

    - by Darren Engwirda
    I'm having some issues using pooled memory allocators for std::list objects in a multi-threaded application. The part of the code I'm concerned with runs each thread function in isolation (i.e. there is no communication or synchronization between threads) and therefore I'd like to setup separate memory pools for each thread, where each pool is not thread-safe (and hence fast). I've tried using a shared thread-safe singleton memory pool and found the performance to be poor, as expected. This is a heavily simplified version of the type of thing I'm trying to do. A lot has been included in a pseudo-code kind of way, sorry if it's confusing. /* The thread functor - one instance of MAKE_QUADTREE created for each thread */ class make_quadtree { private: /* A non-thread-safe memory pool for int linked list items, let's say that it's * something along the lines of BOOST::OBJECT_POOL */ pooled_allocator<int> item_pool; /* The problem! - a local class that would be constructed within each std::list as the * allocator but really just delegates to ITEM_POOL */ class local_alloc { public : //!! I understand that I can't access ITEM_POOL from within a nested class like //!! this, that's really my question - can I get something along these lines to //!! work?? pointer allocate (size_t n) { return ( item_pool.allocate(n) ); } }; public : make_quadtree (): item_pool() // only construct 1 instance of ITEM_POOL per // MAKE_QUADTREE object { /* The kind of data structures - vectors of linked lists * The idea is that all of the linked lists should share a local pooled allocator */ std::vector<std::list<int, local_alloc>> lists; /* The actual operations - too complicated to show, but in general: * * - The vector LISTS is grown as a quadtree is built, it's size is the number of * quadtree "boxes" * * - Each element of LISTS (each linked list) represents the ID's of items * contained within each quadtree box (say they're xy points), as the quadtree * is grown a lot of ID pop/push-ing between lists occurs, hence the memory pool * is important for performance */ } }; So really my problem is that I'd like to have one memory pool instance per thread functor instance, but within each thread functor share the pool between multiple std::list objects.

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  • highlight query string in more than one field using solr search feature

    - by Romi
    i am using solr indexes for showing my search results. to show serch results i am parsing json data received from solr. i am able to highlight a query string in search result but only in a single field. for this i set hl=true and hl.fl="field1". i did it as $.getJSON("http://192.168.1.9:8983/solr/db/select/?wt=json&&start=0&rows=100&q="+lowerCaseQuery+"&hl=true&hl.fl=description,name&hl.usePhraseHighlighter=true&sort=price asc&json.wrf=?", function(result){ var n=result.response.numFound var highlight = new Array(n); $.each(result.highlighting, function(i, hitem){ var match = hitem.text[0].match(/<em>(.*?)<\/em>/); highlight[i]=match[1]; }); $.each(newresult.response.docs, function(i,item){ var word=highlight[item["UID_PK"]]; var result = item.text[0].replace(new RegExp(word,'g'), '<em>' + word + '</em>'); }); for this json object is as : { "responseHeader": { "status": 0, "QTime": 32 }, "response": { "numFound": 21, "start": 0, "docs": [ { "description": "The matte finish waves on this wedding band contrast with the high polish borders. This sharp and elegant design was finely crafted in Japan.", "UID_PK": "8252", }, { "description": "This elegant ring has an Akoya cultured pearl with a band of bezel-set round diamonds making it perfect for her to wear to work or the night out.", "UID_PK": "8142", }, ] }, "highlighting": { "8252": { "description": [ " and <em>elegant</em> design was finely crafted in Japan." ] }, "8142": { "description": [ "This <em>elegant</em> ring has an Akoya cultured pearl with a band of bezel-set round diamonds making" ] }, } } Now if i want to highlight query string in two fields i did as hl=true hl.fl=descrption, name my json is as: { "responseHeader":{ "status":0, "QTime":16 }, "response":{ "numFound":1904, "start":0, "docs":[ { "description":"", "UID_PK":"7780", "name":[ "Diamond bracelet with Milgrain Bezel1" ] }, { "description":"This pendant is sure to win hearts. Round diamonds form a simple and graceful line.", "UID_PK":"8121", "name":[ "Heartline Diamond Pendant" ] }, "highlighting":{ "7780":{ "name":[ "<em>Diamond</em> bracelet with Milgrain Bezel1" ] }, "8121":{ "description":[ "This pendant is sure to win hearts. Round <em>diamonds</em> form a simple and graceful line." ], "name":[ "Heartline <em>Diamond</em> Pendant" ] } } } Now how should i parse it to get the result. suggest me some general technique, so if i want to highlight query in more fields then i could do so. Thanks

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  • How do you remind your Scrum Product Owner about his promises/actions?

    - by Felix Ogg
    ** EDIT: Rephrased the question to re-focus ** Our Scrum team meets as seldomly as possible, but we meet with the product owner every chance we get. We track everyone's agreed action points (particularly theirs). We are 100% agile, but our product owner lives in traditional world, we remain off-site. We facilitate him in crossing over to our fast-paced world. There's not much wrong. The team and the PO are in good spirits. PO is present at every meeting and positively energized. Just imagine this person as a 70 year old, slow grandpa, who is forgetful, yet kind. In reality he isn't, but he is used to a working environment (public servants) that is much slooooower. Manyana-manyana etc. It is frustrating for my team to cooperate: PO lives in a non-prioritized environment, and everyone in it has learned the productivity-technique of NGTD (Not Getting Things Done). He WANTS to, it's just that he forgets or 'sinks' somewhere along the away. We have experimented with a text file, maintained by the Scrum master (low-tech), which he broadcasts by e-mail every day JIRA, our issue tracker. Turns out this is nice for programmers, but too steep for 'regular people' I Googled for Issue tracking webtools but came up empty handed: All tools are aimed at IT issue tracking, instead of meeting action point tracking/planning for mere mortals. I did find TODO-lists like RememberTheMilk, but they don't track comments, and - to be honest - I doubt we could get our product owner to use it (too complicated). We have three requirements: Register action points, assign to a team member and a deadline Offer anyone to 'comment' on progress of any action point Do not build our own tool from scratch We do not need: - impressive authorization models, - multi-project, - workflow, - crosslinking. Is there any trick/tool you use to assist your product owner 'fly' like the rest of the rest of the team? Communication before tools I agree with the general consensus that one should not try to apply technology to a communication problem, however in this case I am merely looking for a tool to save me time in setting up prioritized lists. I found www.thymer.com today, may be what I am looking for. The guys are cool. It is getting rather feature-bloated though.

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  • Design patterns and interview question

    - by user160758
    When I was learning to code, I read up on the design patterns like a good boy. Long after this, I started to actually understand them. Design discussions such as those on this site constantly try to make the rules more and more general, which is good. But there is a line, over which it becomes over-analysis starts to feed off itself and as such I think begins to obfuscate the original point - for example the "What's Alternative to Singleton" post and the links contained therein. http://stackoverflow.com/questions/1300655/whats-alternative-to-singleton I say this having been asked in both interviews I’ve had over the last 2 weeks what a singleton is and what criticisms I have of it. I have used it a few times for items such as user data (simple key-value eg. last file opened by this user) and logging (very common i'm sure). I've never ever used it just to have what is essentially global application data, as this is clearly stupid. In the first interview, I reply that I have no criticisms of it. He seemed disappointed by this but as the job wasn’t really for me, I forgot about it. In the next one, I was asked again and, as I wanted this job, I thought about it on the spot and made some objections, similar to those contained in the post linked to above (I suggested use of a factory or dependency injection instead). He seemed happy with this. But my problem is that I have used the singleton without ever using it in this kind of stupid way, which I had to describe on the spot. Using it for global data and the like isn’t something I did then realised was stupid, or read was stupid so didn’t do, it was just something I knew was stupid from the start. Essentially I’m supposed to be able to think of ways of how to misuse a pattern in the interview? Which class of programmers can best answer this question? The best ones? The medium ones? I'm not sure.... And these were both bright guys. I read more than enough to get better at my job but had never actually bothered to seek out criticisms of the most simple of the design patterns like this one. Do people think such questions are valid and that I ought to know the objections off by heart? Or that it is reasonable to be able to work out what other people who are missing the point would do on the fly? Or do you think I’m at least partially right that the question is too unsubtle and that the questions ought to be better thought out in order to make sure only good candidates can answer. PS. Please don’t think I’m saying that I’m just so clever that I know everything automatically - I’ve learnt the hard way like everyone else. But avoiding global data is hardly revolutionary.

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  • WPF: Improving Performance for Running on Older PCs

    - by Phil Sandler
    So, I'm building a WPF app and did a test deployment today, and found that it performed pretty poorly. I was surprised, as we are really not doing much in the way of visual effects or animations. I deployed on two machines: the fastest and the slowest that will need to run the application (the slowest PC has an Intel Celeron 1.80GHz with 2GB RAM). The application ran pretty well on the faster machine, but was choppy on the slower machine. And when I say "choppy", I mean the cursor jumped even just passing it over any open window of the app that had focus. I opened the Task Manager Performance window, and could see that the CPU usage jumped whenever the app had focus and the cursor was moving over it. If I gave focus to another (e.g. Excel), the CPU usage went back down after a second. This happened on both machines, but the choppiness was only noticeable on the slower machine. I had very limited time to tinker on the deployment machines, so didn't do a lot of detailed testing. The app runs fine on my development machine, but I also see the CPU spiking up to 10% there, just running the cursor over the window. I downloaded the WPF performance tool from MS and have been tinkering with it (on my dev machine). The docs say this about the "Frame Rate" metric in the Perforator tool: For applications without animation, this value should be near 0. The app is not doing any heavy animation, but the frame rate stays near 50 when the cursor is over any window. The screens I tested on have column headers in a grid that "highlight" and buttons that change color and appearance when scrolled over. Even moving the mouse on blank areas of the windows cause the same Frame rate and CPU usage (doesn't seem to be related to these minor animations). (Also, I am unable to figure out how to get anything but the two default tools--Perforator and Visual Profiler--installed into the WPF performance tool. That is probably a separate question). I also have Redgate's profiling tool, but I'm not sure if that can shed any light on rendering performance. So, I realize this is not an easy thing to troubleshoot without specifics or sample code (which I can't post). My questions are: What are some general things to look for (or avoid) in the code to improve performance? What steps can I take using the WPF performance tool to narrow down the problem? Is the PC spec listed above (Intel Celeron 1.80GHz with 2GB RAM) too slow to be running even vanilla WPF applications?

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  • Remove links with Javascript

    - by Arlen Beiler
    How do I remove links from a webpage with Javascript. I am using Google Chrome. The code I tried is: function removehyperlinks() { try { alert(document.anchors.length); alert(document.getElementsByTagName('a')); for(i=0;i=document.anchors.length;i++) { var a = document.anchors[i]; a.outerHTML = a.innerHTML; var b = document.getElementsByTagName('a'); b[i].outerHTML = b[i].innerHTML; } } catch(e) { alert (e);} alert('done'); } Of course, this is test code, which is why I have the alerts and 2 things trying at the same time. The first alert returns "0" the second [Object NodeList] and the third returns "done". My html body looks like this: <body onload="removehyperlinks()"> <ol style="text-align:left;" class="messagelist"> <li class="accesscode"><a href="#">General information, Updates, &amp; Meetings<span class="extnumber">141133#</span></a> <ol> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li start="77"><a href="#"">...</a></li> <li start="88"><a href="#">...</a></li> <li start="99"><a href="#">...</a></li> </ol> </li> </ol> </body>

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  • Throwing cats out of windows

    - by AndrewF
    Imagine you're in a tall building with a cat. The cat can survive a fall out of a low story window, but will die if thrown from a high floor. How can you figure out the longest drop that the cat can survive, using the least number of attempts? Obviously, if you only have one cat, then you can only search linearly. First throw the cat from the first floor. If it survives, throw it from the second. Eventually, after being thrown from floor f, the cat will die. You then know that floor f-1 was the maximal safe floor. But what if you have more than one cat? You can now try some sort of logarithmic search. Let's say that the build has 100 floors and you have two identical cats. If you throw the first cat out of the 50th floor and it dies, then you only have to search 50 floors linearly. You can do even better if you choose a lower floor for your first attempt. Let's say that you choose to tackle the problem 20 floors at a time and that the first fatal floor is #50. In that case, your first cat will survive flights from floors 20 and 40 before dying from floor 60. You just have to check floors 41 through 49 individually. That's a total of 12 attempts, which is much better than the 50 you would need had you attempted to use binary elimination. In general, what's the best strategy and it's worst-case complexity for an n-storied building with 2 cats? What about for n floors and m cats? Assume that all cats are equivalent: they will all survive or die from a fall from a given window. Also, every attempt is independent: if a cat survives a fall, it is completely unharmed. This isn't homework, although I may have solved it for school assignment once. It's just a whimsical problem that popped into my head today and I don't remember the solution. Bonus points if anyone knows the name of this problem or of the solution algorithm.

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  • Converting C source to C++

    - by Barry Kelly
    How would you go about converting a reasonably large (300K), fairly mature C codebase to C++? The kind of C I have in mind is split into files roughly corresponding to modules (i.e. less granular than a typical OO class-based decomposition), using internal linkage in lieu private functions and data, and external linkage for public functions and data. Global variables are used extensively for communication between the modules. There is a very extensive integration test suite available, but no unit (i.e. module) level tests. I have in mind a general strategy: Compile everything in C++'s C subset and get that working. Convert modules into huge classes, so that all the cross-references are scoped by a class name, but leaving all functions and data as static members, and get that working. Convert huge classes into instances with appropriate constructors and initialized cross-references; replace static member accesses with indirect accesses as appropriate; and get that working. Now, approach the project as an ill-factored OO application, and write unit tests where dependencies are tractable, and decompose into separate classes where they are not; the goal here would be to move from one working program to another at each transformation. Obviously, this would be quite a bit of work. Are there any case studies / war stories out there on this kind of translation? Alternative strategies? Other useful advice? Note 1: the program is a compiler, and probably millions of other programs rely on its behaviour not changing, so wholesale rewriting is pretty much not an option. Note 2: the source is nearly 20 years old, and has perhaps 30% code churn (lines modified + added / previous total lines) per year. It is heavily maintained and extended, in other words. Thus, one of the goals would be to increase mantainability. [For the sake of the question, assume that translation into C++ is mandatory, and that leaving it in C is not an option. The point of adding this condition is to weed out the "leave it in C" answers.]

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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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  • Template function as a template argument

    - by Kos
    I've just got confused how to implement something in a generic way in C++. It's a bit convoluted, so let me explain step by step. Consider such code: void a(int) { // do something } void b(int) { // something else } void function1() { a(123); a(456); } void function2() { b(123); b(456); } void test() { function1(); function2(); } It's easily noticable that function1 and function2 do the same, with the only different part being the internal function. Therefore, I want to make function generic to avoid code redundancy. I can do it using function pointers or templates. Let me choose the latter for now. My thinking is that it's better since the compiler will surely be able to inline the functions - am I correct? Can compilers still inline the calls if they are made via function pointers? This is a side-question. OK, back to the original point... A solution with templates: void a(int) { // do something } void b(int) { // something else } template<void (*param)(int) > void function() { param(123); param(456); } void test() { function<a>(); function<b>(); } All OK. But I'm running into a problem: Can I still do that if a and b are generics themselves? template<typename T> void a(T t) { // do something } template<typename T> void b(T t) { // something else } template< ...param... > // ??? void function() { param<SomeType>(someobj); param<AnotherType>(someotherobj); } void test() { function<a>(); function<b>(); } I know that a template parameter can be one of: a type, a template type, a value of a type. None of those seems to cover my situation. My main question is hence: How do I solve that, i.e. define function() in the last example? (Yes, function pointers seem to be a workaround in this exact case - provided they can also be inlined - but I'm looking for a general solution for this class of problems).

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