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  • PHP Parse Error unexpected '{'

    - by Laxmidi
    Hi, I'm getting a "Parse error: syntax error, unexpected '{' in line 2". And I don't see the problem. <?php class pointLocation {     var $pointOnVertex = true; // Check if the point sits exactly on one of the vertices     function pointLocation() {     }                   function pointInPolygon($point, $polygon, $pointOnVertex = true) {         $this->pointOnVertex = $pointOnVertex;                  // Transform string coordinates into arrays with x and y values         $point = $this->pointStringToCoordinates($point);         $vertices = array();          foreach ($polygon as $vertex) {             $vertices[] = $this->pointStringToCoordinates($vertex);          }                  // Check if the point sits exactly on a vertex         if ($this->pointOnVertex == true and $this->pointOnVertex($point, $vertices) == true) {             return "vertex";         }                  // Check if the point is inside the polygon or on the boundary         $intersections = 0;          $vertices_count = count($vertices);              for ($i=1; $i < $vertices_count; $i++) {             $vertex1 = $vertices[$i-1];              $vertex2 = $vertices[$i];             if ($vertex1['y'] == $vertex2['y'] and $vertex1['y'] == $point['y'] and $point['x'] > min($vertex1['x'], $vertex2['x']) and $point['x'] < max($vertex1['x'], $vertex2['x'])) { // Check if point is on an horizontal polygon boundary                 return "boundary";             }             if ($point['y'] > min($vertex1['y'], $vertex2['y']) and $point['y'] <= max($vertex1['y'], $vertex2['y']) and $point['x'] <= max($vertex1['x'], $vertex2['x']) and $vertex1['y'] != $vertex2['y']) {                  $xinters = ($point['y'] - $vertex1['y']) * ($vertex2['x'] - $vertex1['x']) / ($vertex2['y'] - $vertex1['y']) + $vertex1['x'];                  if ($xinters == $point['x']) { // Check if point is on the polygon boundary (other than horizontal)                     return "boundary";                 }                 if ($vertex1['x'] == $vertex2['x'] || $point['x'] <= $xinters) {                     $intersections++;                  }             }          }          // If the number of edges we passed through is even, then it's in the polygon.          if ($intersections % 2 != 0) {             return "inside";         } else {             return "outside";         }     }               function pointOnVertex($point, $vertices) {         foreach($vertices as $vertex) {             if ($point == $vertex) {                 return true;             }         }          }                   function pointStringToCoordinates($pointString) {         $coordinates = explode(" ", $pointString);         return array("x" => $coordinates[0], "y" => $coordinates[1]);     }           } $pointLocation = new pointLocation(); $points = array("30 19", "0 0", "10 0", "30 20", "11 0", "0 11", "0 10", "30 22", "20 20"); $polygon = array("10 0", "20 0", "30 10", "30 20", "20 30", "10 30", "0 20", "0 10", "10 0"); foreach($points as $key => $point) { echo "$key ($point) is " . $pointLocation->pointInPolygon($point, $polygon) . "<br>"; } ?> Does anyone see the problem? Thanks, -Laxmidi

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  • Flex/Air/AS3 Selecting and Populating a unFocused tab.

    - by Deyon
    I'm having a problem displaying data from a function to text box within a tab. If you run the code and click "Select Tab 2 and Fill..." I get an error; "TypeError: Error #1009: Cannot access a property or method of a null object reference." I'm guessing this is because "Tab 2" is/was not rendered yet. Now if I run the code, select "Tab 2" then select "Tab 1" and click "Select Tab 2 and Fill..." it works the way I would like. Dose any one know a way around this problem. ----Full Flex 4/Flash Builder Code just copy paste---- <?xml version="1.0" encoding="utf-8"?> <s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/halo" creationComplete=" "> <fx:Script> <![CDATA[ public function showtab2():void { mytextbox.text="I made it!"; tn.selectedIndex=1; } ]]> </fx:Script> <fx:Declarations> <!-- Place non-visual elements (e.g., services, value objects) here --> </fx:Declarations> <mx:Panel title="TabNavigator Container Example" height="90%" width="90%" paddingTop="10" paddingLeft="10" paddingRight="10" paddingBottom="10"> <mx:Label width="100%" color="blue" text="Select the tabs to change the panel."/> <mx:TabNavigator id="tn" width="100%" height="100%"> <!-- Define each panel using a VBox container. --> <mx:VBox label="Panel 1"> <mx:Label text="TabNavigator container panel 1"/> <mx:Button label="Select Tab 2 and Fill with Text" click="showtab2()"/> </mx:VBox> <mx:VBox label="Panel 2"> <mx:Label text="TabNavigator container panel 2"/> <s:TextInput id="mytextbox" /> </mx:VBox> </mx:TabNavigator> <mx:HBox> </mx:HBox> </mx:Panel> </s:WindowedApplication>

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  • Few iPhone noob questions

    - by mshsayem
    Why should I declare local variables as 'static' inside a method? Like: static NSString *cellIdentifier = @"Cell"; Is it a performance advantage? (I know what 'static' does; in C context) What does this syntax mean?[someObj release], someObj = nil; Two statements? Why should I assign nil again? Is not 'release' enough? Should I do it for all objects I allocate/own? Or for just view objects? Why does everyone copy NSString, but retains other objects (in property declaration)? Yes, NSStrings can be changed, but other objects can be changed also, right? Then why 'copy' for just NSString, not for all? Is it just a defensive convention? Shouldn't I release constant NSString? Like here:NSString *CellIdentifier = @"Cell"; Why not? Does the compiler allocate/deallocate it for me? In some tutorial application I observed these (Built with IB): Properties(IBOutlet, with same ivar name): window, someLabel, someTextField, etc etc... In the dealloc method, although the window ivar was released, others were not. My question is: WHY? Shouldn't I release other ivars(labels, textField) as well? Why not? Say, I have 3 cascaded drop-down lists. I mean, based on what is selected on the first list, 2nd list is populated and based on what is selected on the second list, 3rd list is populated. What UI components can reflect this best? How is drop-down list presented in iPhone UI? Tableview with UIPicker? When should I update the 2nd, 3rd list? Or just three labels which have touch events? Can you give me some good example tutorials about Core-Data? (Not just simple data fetching and storing on 2/3 tables with 1/2 relationship) How can I know whether my app is leaking memory? Any tools?

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  • How do you return a pointer to a base class with a virtual function?

    - by Nick Sweet
    I have a base class called Element, a derived class called Vector, and I'm trying to redefine two virtual functions from Element in Vector. //element.h template <class T> class Element { public: Element(); virtual Element& plus(const Element&); virtual Element& minus(const Element&); }; and in another file //Vector.h #include "Element.h" template <class T> class Vector: public Element<T> { T x, y, z; public: //constructors Vector(); Vector(const T& x, const T& y = 0, const T& z =0); Vector(const Vector& u); ... //operations Element<T>& plus(const Element<T>& v) const; Element<T>& minus(const Element<T>& v) const; ... }; //sum template <class T> Element<T>& Vector<T>::plus(const Element<T>& v) const { Element<T>* ret = new Vector((x + v.x), (y + v.y), (z + v.z)); return *ret; } //difference template <class T> Element<T>& Vector<T>::minus(const Element<T>& v) const { Vector<T>* ret = new Vector((x - v.x), (y - v.y), (z - v.z)); return *ret; } but I always get error: 'const class Element' has no member named 'getx' So, can I define my virtual functions to take Vector& as an argument instead, or is there a way for me to access the data members of Vector through a pointer to Element? I'm still fairly new to inheritance polymorphism, fyi.

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  • Delphi Unit local variables - how to make each instance unique?

    - by Justin
    Ok, this, I'm sure is something simple that is easy to do. The problem : I've inherited scary spaghetti code and am slowly trying to better it when new features need adding - generally when a refactor makes adding the new feature neater. I've got a bunch of code I'm packing into a single unit which, in different places in the application, controls the same physical thing in the outside world. The control appears in several places in the application and operates slightly differently in each instance. What I've done is to create a unit with all of the features I need which I can simply drop, as a frame, into each form that requires it. Each form then uses the unit's interface methods to customise the behaviour for each instance. The problem within the problem : In the unit in question (the frame) I have a variable declared in the IMPLEMENTATION section - local to the unit. I also have a procedure, declared in the TYPE section which takes an argument and assigns that argument to the local variable in question - each form passes a unique variable to each instance of the frame/unit. What I want it to do is for each instance of the frame to keep its own version of that variable, different from the others, and use that to define how it operates. What seems to be happening, however, is that all instances are using the same value, even if I explicitly pass each instance a different variable. ie: Unit FlexibleUnit; interface uses //the uses stuff type TFlexibleUnit=class(TFrame) //declarations including procedure makeThisInstanceX(passMeTheVar:integer); private // public // end; implementation uses //the uses var myLocalVar; procedure makeThisInstanceX(passMeTheVar:integer); begin myLocalVar:=passMeTheVar; end; //other procedures using myLocalVar //etc to the end; Now somewhere in another Form I've dropped this Frame onto the Design pane, sometimes two of these frames on one Form, and have it declared in the proper places, etc. Each is unique in that : ThisFlexibleUnit : TFlexibleUnit; ThatFlexibleUnit : TFlexibleUnit; and when I do a: ThisFlexibleUnit.makeThisInstanceX(var1); //want to behave in way "var1" ThatFlexibleUnit.makeThisInstanceX(var2); //want to behave in way "var2" it seems that they both share the same variable "myLocalVar". Am I doing this wrong, in principle? If this is the correct method then it's a matter of debugging what I have (which is too huge to post) but if this is not correct in principle then is there a way to do what I am suggesting? Thanks in advance, Stack Overflow - you guys (and gals!) are legendary.

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  • Writing a managed wrapper for unmanaged (C++) code - custom types/structs

    - by Bobby
    faacEncConfigurationPtr FAACAPI faacEncGetCurrentConfiguration( faacEncHandle hEncoder); I'm trying to come up with a simple wrapper for this C++ library; I've never done more than very simple p/invoke interop before - like one function call with primitive arguments. So, given the above C++ function, for example, what should I do to deal with the return type, and parameter? FAACAPI is defined as: #define FAACAPI __stdcall faacEncConfigurationPtr is defined: typedef struct faacEncConfiguration { int version; char *name; char *copyright; unsigned int mpegVersion; unsigned long bitRate; unsigned int inputFormat; int shortctl; psymodellist_t *psymodellist; int channel_map[64]; } faacEncConfiguration, *faacEncConfigurationPtr; AFAIK this means that the return type of the function is a reference to this struct? And faacEncHandle is: typedef struct { unsigned int numChannels; unsigned long sampleRate; ... SR_INFO *srInfo; double *sampleBuff[MAX_CHANNELS]; ... double *freqBuff[MAX_CHANNELS]; double *overlapBuff[MAX_CHANNELS]; double *msSpectrum[MAX_CHANNELS]; CoderInfo coderInfo[MAX_CHANNELS]; ChannelInfo channelInfo[MAX_CHANNELS]; PsyInfo psyInfo[MAX_CHANNELS]; GlobalPsyInfo gpsyInfo; faacEncConfiguration config; psymodel_t *psymodel; /* quantizer specific config */ AACQuantCfg aacquantCfg; /* FFT Tables */ FFT_Tables fft_tables; int bitDiff; } faacEncStruct, *faacEncHandle; So within that struct we see a lot of other types... hmm. Essentially, I'm trying to figure out how to deal with these types in my managed wrapper? Do I need to create versions of these types/structs, in C#? Something like this: [StructLayout(LayoutKind.Sequential)] struct faacEncConfiguration { uint useTns; ulong bitRate; ... } If so then can the runtime automatically "map" these objects onto eachother? And, would I have to create these "mapped" types for all the types in these return types/parameter type hierarchies, all the way down until I get to all primitives? I know this is a broad topic, any advice on getting up-to-speed quickly on what I need to learn to make this happen would be very much appreciated! Thanks!

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  • How to cache queries in EJB and return result efficient (performance POV)

    - by Maxym
    I use JBoss EJB 3.0 implementation (JBoss 4.2.3 server) At the beginning I created native query all the time using construction like Query query = entityManager.createNativeQuery("select * from _table_"); Of couse it is not that efficient, I performed some tests and found out that it really takes a lot of time... Then I found a better way to deal with it, to use annotation to define native queries: @NamedNativeQuery( name = "fetchData", value = "select * from _table_", resultClass=Entity.class ) and then just use it Query query = entityManager.createNamedQuery("fetchData"); the performance of code line above is two times better than where I started from, but still not that good as I expected... then I found that I can switch to Hibernate annotation for NamedNativeQuery (anyway, JBoss's implementation of EJB is based on Hibernate), and add one more thing: @NamedNativeQuery( name = "fetchData2", value = "select * from _table_", resultClass=Entity.class, readOnly=true) readOnly - marks whether the results are fetched in read-only mode or not. It sounds good, because at least in this case of mine I don't need to update data, I wanna just fetch it for report. When I started server to measure performance I noticed that query without readOnly=true (by default it is false) returns result with each iteration better and better, and at the same time another one (fetchData2) works like "stable" and with time difference between them is shorter and shorter, and after 5 iterations speed of both was almost the same... The questions are: 1) is there any other way to speed query using up? Seems that named queries should be prepared once, but I can't say it... In fact if to create query once and then just use it it would be better from performance point of view, but it is problematic to cache this object, because after creating query I can set parameters (when I use ":variable" in query), and it changes query object (isn't it?). well, is here any way to cache them? Or named query is the best option I can use? 2) any other approaches how to make results retrieveng faster. I mean, for instance I don't need those Entities to be attached, I won't update them, all I need is just fetch collection of data. Maybe readOnly is the only available way, so I can't speed it up, but who knows :) P.S. I don't ask about DB performance, all I need now is how not to create query all the time, so use it efficient, and to "allow" EJB to do less job with the same result concerning data returning.

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  • Autoconf -- building with static library (newbie)

    - by EB
    I am trying to migrate my application from manual build to autoconf, which is working very nicely so far. But I have one static library that I can't figure out how to integrate. That library will NOT be located in the usual library locations - the location of the binary (.a file) and header (.h file) will be given as a configure argument. (Notably, even if I move the .a file to /usr/lib or anywhere else I can think of, it still won't work.) It is also not named traditionally (it does not start with "lib" or "l"). Manual compilation is working with these (directory is not predictable - this is just an example): gcc ... -I/home/john/mystuff /home/john/mystuff/helper.a (Uh, I actually don't understand why the .a file is referenced directly, not with -L or anything. Yes, I have a half-baked understanding of building C programs.) So, in my configure.ac, I can use the relevant configure argument to successfully find the header (.h file) using AC_CHECK_HEADER. Inside the AC_CHECK_HEADER I then add the location to CPFLAGS and the #include of the header file in the actual C code picks it up nicely. Given a configure argument that has been put into $location and the name of the needed files are helper.h and helper.a (which are both in the same directory), here is what works so far: AC_CHECK_HEADER([$location/helper.h], [AC_DEFINE([HAVE_HELPER_H], [1], [found helper.h]) CFLAGS="$CFLAGS -I$location"]) Where I run into difficulties is getting the binary (.a file) linked in. No matter what I try, I always get an error about undefined references to the function calls for that library. I'm pretty sure it's a linkage issue, because I can fuss with the C code and make an intentional error in the function calls to that library which produces earlier errors that indicate that the function prototypes have been loaded and used to compile. I tried adding the location that contains the .a file to LDFLAGS and then doing a AC_CHECK_LIB but it is not found. Maybe my syntax is wrong, or maybe I'm missing something more fundamental, which would not be surprising since I'm a newbie and don't really know what I'm doing. Here is what I have tried: AC_CHECK_HEADER([$location/helper.h], [AC_DEFINE([HAVE_HELPER_H], [1], [found helper.h]) CFLAGS="$CFLAGS -I$location"; LDFLAGS="$LDFLAGS -L$location"; AC_CHECK_LIB(helper)]) No dice. AC_CHECK_LIB is looking for -lhelper I guess (or libhelper?) so I'm not sure if that's a problem, so I tried this, too (omit AC_CHECK_LIB and include the .a directly in LDFLAGS), without luck: AC_CHECK_HEADER([$location/helper.h], [AC_DEFINE([HAVE_HELPER_H], [1], [found helper.h]) CFLAGS="$CFLAGS -I$location"; LDFLAGS="$LDFLAGS -L$location/helper.a"]) To emulate the manual compilation, I tried removing the -L but that doesn't help: AC_CHECK_HEADER([$location/helper.h], [AC_DEFINE([HAVE_HELPER_H], [1], [found helper.h]) CFLAGS="$CFLAGS -I$location"; LDFLAGS="$LDFLAGS $location/helper.a"]) I tried other combinations and permutations, but I think I might be missing something more fundamental....

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  • Having trouble wrapping functions in the linux kernel

    - by Corey Henderson
    I've written a LKM that implements Trusted Path Execution (TPE) into your kernel: https://github.com/cormander/tpe-lkm I run into an occasional kernel OOPS (describe at the end of this question) when I define WRAP_SYSCALLS to 1, and am at my wit's end trying to track it down. A little background: Since the LSM framework doesn't export its symbols, I had to get creative with how I insert the TPE checking into the running kernel. I wrote a find_symbol_address() function that gives me the address of any function I need, and it works very well. I can call functions like this: int (*my_printk)(const char *fmt, ...); my_printk = find_symbol_address("printk"); (*my_printk)("Hello, world!\n"); And it works fine. I use this method to locate the security_file_mmap, security_file_mprotect, and security_bprm_check functions. I then overwrite those functions with an asm jump to my function to do the TPE check. The problem is, the currently loaded LSM will no longer execute the code for it's hook to that function, because it's been totally hijacked. Here is an example of what I do: int tpe_security_bprm_check(struct linux_binprm *bprm) { int ret = 0; if (bprm->file) { ret = tpe_allow_file(bprm->file); if (IS_ERR(ret)) goto out; } #if WRAP_SYSCALLS stop_my_code(&cs_security_bprm_check); ret = cs_security_bprm_check.ptr(bprm); start_my_code(&cs_security_bprm_check); #endif out: return ret; } Notice the section between the #if WRAP_SYSCALLS section (it's defined as 0 by default). If set to 1, the LSM's hook is called because I write the original code back over the asm jump and call that function, but I run into an occasional kernel OOPS with an "invalid opcode": invalid opcode: 0000 [#1] SMP RIP: 0010:[<ffffffff8117b006>] [<ffffffff8117b006>] security_bprm_check+0x6/0x310 I don't know what the issue is. I've tried several different types of locking methods (see the inside of start/stop_my_code for details) to no avail. To trigger the kernel OOPS, write a simple bash while loop that endlessly starts a backgrounded "ls" command. After a minute or so, it'll happen. I'm testing this on a RHEL6 kernel, also works on Ubuntu 10.04 LTS (2.6.32 x86_64). While this method has been the most successful so far, I have tried another method of simply copying the kernel function to a pointer I created with kmalloc but when I try to execute it, I get: kernel tried to execute NX-protected page - exploit attempt? (uid: 0). If anyone can tell me how to kmalloc space and have it marked as executable, that would also help me solve the above problem. Any help is appreciated!

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  • C++ Undeclared Identifier (but it is declared?)

    - by Joshua
    I'm pretty sure I've included the qanda class, but when I try to declare a vector that contains it or a class of that type I get an error saying that qanda is undefined. Any idea what the problem might be? bot_manager_item.h #pragma once #include "../bot_packet/bot_packet.h" #include <vector> class bot_manager_item; #include "qanda.h" #include "bot_manager.h" class bot_manager_item { public: bot_manager_item(bot_manager* mngr, const char* name, const char* work_dir); ~bot_manager_item(); bool startup(); void cleanup(); void on_push_event(bot_exchange_format f); bool disable; private: void apply_changes(); bot_manager *_mngr; std::string _name; std::string _work_dir; std::string _message; std::string _message_copy; std::vector<qanda> games; qanda test; char _config_full_path[2600]; }; qanda.h #ifndef Q_AND_A #define Q_AND_A #include "users.h" #include "..\bot_packet\bot_packet.h" #include "bot_manager.h" #include <string> #include <algorithm> #include <map> #include <vector> #include <fstream> class qanda { public: qanda(bot_manager * manager, std::string name, std::string directory); ~qanda(){}; void room_message(std::string username, std::string user_message); void timer_tick(); private: // data members std::string question; std::string answer; std::string directory; std::string command_prefix; std::string name; Users users; std::map <std::string, std::string> questions_and_answers; int time_per_question; // seconds int time_between_questions; // seconds int timer; // milliseconds bool is_delayed; bool is_playing; bot_manager * manager; // functions void new_question(); void send_message(std::string msg); void announce_question(); void load_questions(); }; #endif

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  • How do I code a loop for my echo statements?

    - by ggg
    <?php defined('_JEXEC') or die('Restricted access'); $db =& JFactory::getDBO(); $query0 = "SELECT * FROM `#__chesspositions` WHERE . . . . ."; //echo $query0; $db->setQuery($query0); $ginfo = $db->loadObjectList(); //echo $ginfo[0]; echo $db->getErrorMsg(); if(empty($ginfo)){ echo "<center><h2 style='color:navy'>No game found, we apologize</h2></center>"; }else{ $query1= "SELECT * FROM `#__chessmoves` WHERE Id='".$ginfo[0]->MoveDataId."'"; $db->setQuery($query1); echo $db->getErrorMsg(); $gmove = $db->loadObjectList(); } //define array; //how do I code a foreach loop (or any other type of loop) here? //I'm having trouble properly defining the array and structuring the syntax. echo "[Event \"".$ginfo[0]->Event."\"]\n"; echo "[Site \"".$ginfo[0]->Site."\"]\n"; echo "[Date \"".$ginfo[0]->Date."\"]\n"; echo "[Round \"".$ginfo[0]->Round."\"]\n"; echo "[White \"".$ginfo[0]->White."\"]\n"; echo "[Black \"".$ginfo[0]->Black."\"]\n"; echo "[Result \"".$ginfo[0]->Result."\"]\n"; echo "[ECO \"".$ginfo[0]->ECO."\"]\n"; echo "[WhiteElo \"".$ginfo[0]->WhiteElo."\"]\n"; echo "[BlackElo \"".$ginfo[0]->BlackElo."\"]\n"; echo "[Annotator \"".$ginfo[0]->Annotator."\"]\n"; echo "[SetUp \"".$ginfo[0]->SetUp."\"]\n"; echo $gmove[0]->MoveData; ?>

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  • Displaying pic for user through a question's answer

    - by bgadoci
    Ok, I am trying to display the profile pic of a user. The application I have set up allows users to create questions and answers (I am calling answers 'sites' in the code) the view in which I am trying to do so is in the /views/questions/show.html.erb file. It might also be of note that I am using the Paperclip gem. Here is the set up: Associations Users class User < ActiveRecord::Base has_many :questions, :dependent => :destroy has_many :sites, :dependent => :destroy has_many :notes, :dependent => :destroy has_many :likes, :through => :sites , :dependent => :destroy has_many :pics, :dependent => :destroy has_many :likes, :dependent => :destroy end Questions class Question < ActiveRecord::Base has_many :sites, :dependent => :destroy has_many :notes, :dependent => :destroy has_many :likes, :dependent => :destroy belongs_to :user end Answers (sites) class Site < ActiveRecord::Base belongs_to :question belongs_to :user has_many :notes, :dependent => :destroy has_many :likes, :dependent => :destroy has_attached_file :photo, :styles => { :small => "250x250>" } end Pics class Pic < ActiveRecord::Base has_attached_file :profile_pic, :styles => { :small => "100x100" } belongs_to :user end The /views/questions/show.html.erb is rendering the partial /views/sites/_site.html.erb which is calling the Answer (site) with: <% div_for site do %> <%=h site.description %> <% end %> I have been trying to do things like: <%=image_tag site.user.pic.profile_pic.url(:small) %> <%=image_tag site.user.profile_pic.url(:small) %> etc. But that is obviously wrong. My error directs me to the Questions#show action so I am imagining that I need to define something in there but not sure what. Is is possible to call the pic given the current associations, placement of the call, and if so what Controller additions do I need to make, and what line of code will call the pic? UPDATE: Here is the QuestionsController#show code: def show @question = Question.find(params[:id]) @sites = @question.sites.all(:select => "sites.*, SUM(likes.like) as like_total", :joins => "LEFT JOIN likes AS likes ON likes.site_id = sites.id", :group => "sites.id", :order => "like_total DESC") respond_to do |format| format.html # show.html.erb format.xml { render :xml => @question } end end

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  • Java Best Practice for type resolution at runtime.

    - by Brian
    I'm trying to define a class (or set of classes which implement the same interface) that will behave as a loosely typed object (like JavaScript). They can hold any sort of data and operations on them depend on the underlying type. I have it working in three different ways but none seem ideal. These test versions only allow strings and integers and the only operation is add. Adding integers results in the sum of the integer values, adding strings concatenates the strings and adding an integer to a string converts the integer to a string and concatenates it with the string. The final version will have more types (Doubles, Arrays, JavaScript-like objects where new properties can be added dynamically) and more operations. Way 1: public interface DynObject1 { @Override public String toString(); public DynObject1 add(DynObject1 d); public DynObject1 addTo(DynInteger1 d); public DynObject1 addTo(DynString1 d); } public class DynInteger1 implements DynObject1 { private int value; public DynInteger1(int v) { value = v; } @Override public String toString() { return Integer.toString(value); } public DynObject1 add(DynObject1 d) { return d.addTo(this); } public DynObject1 addTo(DynInteger1 d) { return new DynInteger1(d.value + value); } public DynObject1 addTo(DynString1 d) { return new DynString1(d.toString()+Integer.toString(value)); } } ...and similar for DynString1 Way 2: public interface DynObject2 { @Override public String toString(); public DynObject2 add(DynObject2 d); } public class DynInteger2 implements DynObject2 { private int value; public DynInteger2(int v) { value = v; } @Override public String toString() { return Integer.toString(value); } public DynObject2 add(DynObject2 d) { Class c = d.getClass(); if(c==DynInteger2.class) { return new DynInteger2(value + ((DynInteger2)d).value); } else { return new DynString2(toString() + d.toString()); } } } ...and similar for DynString2 Way 3: public class DynObject3 { private enum ObjectType { Integer, String }; Object value; ObjectType type; public DynObject3(Integer v) { value = v; type = ObjectType.Integer; } public DynObject3(String v) { value = v; type = ObjectType.String; } @Override public String toString() { return value.toString(); } public DynObject3 add(DynObject3 d) { if(type==ObjectType.Integer && d.type==ObjectType.Integer) { return new DynObject3(Integer.valueOf(((Integer)value).intValue()+((Integer)value).intValue())); } else { return new DynObject3(value.toString()+d.value.toString()); } } } With the if-else logic I could use value.getClass()==Integer.class instead of storing the type but with more types I'd change this to use a switch statement and Java doesn't allow switch to use Classes. Anyway... My question is what is the best way to go about something thike this?

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  • MFC: Reading entire file to buffer...

    - by deostroll
    I've meddled with some code but I am unable to read the entire file properly...a lot of junk gets appended to the output. How do I fix this? // wmfParser.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include "wmfParser.h" #include <cstring> #ifdef _DEBUG #define new DEBUG_NEW #endif // The one and only application object CWinApp theApp; using namespace std; int _tmain(int argc, TCHAR* argv[], TCHAR* envp[]) { int nRetCode = 0; // initialize MFC and print and error on failure if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0)) { // TODO: change error code to suit your needs _tprintf(_T("Fatal Error: MFC initialization failed\n")); nRetCode = 1; } else { // TODO: code your application's behavior here. CFile file; CFileException exp; if( !file.Open( _T("c:\\sample.txt"), CFile::modeRead, &exp ) ){ exp.ReportError(); cout<<'\n'; cout<<"Aborting..."; system("pause"); return 0; } ULONGLONG dwLength = file.GetLength(); cout<<"Length of file to read = " << dwLength << '\n'; /* BYTE* buffer; buffer=(BYTE*)calloc(dwLength, sizeof(BYTE)); file.Read(buffer, 25); char* str = (char*)buffer; cout<<"length of string : " << strlen(str) << '\n'; cout<<"string from file: " << str << '\n'; */ char str[100]; file.Read(str, sizeof(str)); cout << "Data : " << str <<'\n'; file.Close(); cout<<"File was closed\n"; //AfxMessageBox(_T("This is a test message box")); system("pause"); } return nRetCode; }

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  • zlib gzgets extremely slow?

    - by monkeyking
    I'm doing stuff related to parsing huge globs of textfiles, and was testing what input method to use. There is not much of a difference using c++ std::ifstreams vs c FILE, According to the documentation of zlib, it supports uncompressed files, and will read the file without decompression. I'm seeing a difference from 12 seconds using non zlib to more than 4 minutes using zlib.h This I've tested doing multiple runs, so its not a disk cache issue. Am I using zlib in some wrong way? thanks #include <zlib.h> #include <cstdio> #include <cstdlib> #include <fstream> #define LENS 1000000 size_t fg(const char *fname){ fprintf(stderr,"\t-> using fgets\n"); FILE *fp =fopen(fname,"r"); size_t nLines =0; char *buffer = new char[LENS]; while(NULL!=fgets(buffer,LENS,fp)) nLines++; fprintf(stderr,"%lu\n",nLines); return nLines; } size_t is(const char *fname){ fprintf(stderr,"\t-> using ifstream\n"); std::ifstream is(fname,std::ios::in); size_t nLines =0; char *buffer = new char[LENS]; while(is. getline(buffer,LENS)) nLines++; fprintf(stderr,"%lu\n",nLines); return nLines; } size_t iz(const char *fname){ fprintf(stderr,"\t-> using zlib\n"); gzFile fp =gzopen(fname,"r"); size_t nLines =0; char *buffer = new char[LENS]; while(0!=gzgets(fp,buffer,LENS)) nLines++; fprintf(stderr,"%lu\n",nLines); return nLines; } int main(int argc,char**argv){ if(atoi(argv[2])==0) fg(argv[1]); if(atoi(argv[2])==1) is(argv[1]); if(atoi(argv[2])==2) iz(argv[1]); }

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  • C strange array behaviour

    - by LukeN
    After learning that both strncmp is not what it seems to be and strlcpy not being available on my operating system (Linux), I figured I could try and write it myself. I found a quote from Ulrich Drepper, the libc maintainer, who posted an alternative to strlcpy using mempcpy. I don't have mempcpy either, but it's behaviour was easy to replicate. First of, this is the testcase I have #include <stdio.h> #include <string.h> #define BSIZE 10 void insp(const char* s, int n) { int i; for (i = 0; i < n; i++) printf("%c ", s[i]); printf("\n"); for (i = 0; i < n; i++) printf("%02X ", s[i]); printf("\n"); return; } int copy_string(char *dest, const char *src, int n) { int r = strlen(memcpy(dest, src, n-1)); dest[r] = 0; return r; } int main() { char b[BSIZE]; memset(b, 0, BSIZE); printf("Buffer size is %d", BSIZE); insp(b, BSIZE); printf("\nFirst copy:\n"); copy_string(b, "First", BSIZE); insp(b, BSIZE); printf("b = '%s'\n", b); printf("\nSecond copy:\n"); copy_string(b, "Second", BSIZE); insp(b, BSIZE); printf("b = '%s'\n", b); return 0; } And this is its result: Buffer size is 10 00 00 00 00 00 00 00 00 00 00 First copy: F i r s t b = 46 69 72 73 74 00 62 20 3D 00 b = 'First' Second copy: S e c o n d 53 65 63 6F 6E 64 00 00 01 00 b = 'Second' You can see in the internal representation (the lines insp() created) that there's some noise mixed in, like the printf() format string in the inspection after the first copy, and a foreign 0x01 in the second copy. The strings are copied intact and it correctly handles too long source strings (let's ignore the possible issue with passing 0 as length to copy_string for now, I'll fix that later). But why are there foreign array contents (from the format string) inside my destination? It's as if the destination was actually RESIZED to match the new length.

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  • Primary language - C++/Qt, C#, Java?

    - by Airjoe
    I'm looking for some input, but let me start with a bit of background (for tl;dr skip to end). I'm an IT major with a concentration in networking. While I'm not a CS major nor do I want to program as a vocation, I do consider myself a programmer and do pretty well with the concepts involved. I've been programming since about 6th grade, started out with a proprietary game creation language that made my transition into C++ at college pretty easy. I like to make programs for myself and friends, and have been paid to program for local businesses. A bit about that- I wrote some programs for a couple local businesses in my senior year in high school. I wrote management systems for local shops (inventory, phone/pos orders, timeclock, customer info, and more stuff I can't remember). It definitely turned out to be over my head, as I had never had any formal programming education. It was a great learning experience, but damn was it crappy code. Oh yeah, by the way, it was all vb6. So, I've used vb6 pretty extensively, I've used c++ in my classes (intro to programming up to algorithms), used Java a little bit in another class (had to write a ping client program, pretty easy) and used Java for some simple Project Euler problems to help learn syntax and such when writing the program for the class. I've also used C# a bit for my own simple personal projects (simple programs, one which would just generate an HTTP request on a list of websites and notify if one responded unexpectedly or not at all, and another which just held a list of things to do and periodically reminded me to do them), things I would've written in vb6 a year or two ago. I've just started using Qt C++ for some undergrad research I'm working on. Now I've had some formal education, I [think I] understand organization in programming a lot better (I didn't even use classes in my vb6 programs where I really should have), how it's important to structure code, split into functions where appropriate, document properly, efficiency both in memory and speed, dynamic and modular programming etc. I was looking for some input on which language to pick up as my "primary". As I'm not a "real programmer", it will be mostly hobby projects, but will include some 'real' projects I'm sure. From my perspective: QtC++ and Java are cross platform, which is cool. Java and C# run in a virtual machine, but I'm not sure if that's a big deal (something extra to distribute, possibly a bit slower? I think Qt would require additional distributables too, right?). I don't really know too much more than this, so I appreciate any help, thanks! TL;DR Am an avocational programmer looking for a language, want quick and straight forward development, liked vb6, will be working with database driven GUI apps- should I go with QtC++, Java, C#, or perhaps something else?

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  • SQL Server 2008: If Multiple Values Set In Other Mutliple Values Set

    - by AJH
    In SQL, is there anyway to accomplish something like this? This is based off a report built in SQL Server Report Builder, where the user can specify multiple text values as a single report parameter. The query for the report grabs all of the values the user selected and stores them in a single variable. I need a way for the query to return only records that have associations to EVERY value the user specified. -- Assume there's a table of Elements with thousands of entries. -- Now we declare a list of properties for those Elements to be associated with. create table #masterTable ( ElementId int, Text varchar(10) ) insert into #masterTable (ElementId, Text) values (1, 'Red'); insert into #masterTable (ElementId, Text) values (1, 'Coarse'); insert into #masterTable (ElementId, Text) values (1, 'Dense'); insert into #masterTable (ElementId, Text) values (2, 'Red'); insert into #masterTable (ElementId, Text) values (2, 'Smooth'); insert into #masterTable (ElementId, Text) values (2, 'Hollow'); -- Element 1 is Red, Coarse, and Dense. Element 2 is Red, Smooth, and Hollow. -- The real table is actually much much larger than this; this is just an example. -- This is me trying to replicate how SQL Server Report Builder treats -- report parameters in its queries. The user selects one, some, all, -- or no properties from a list. The written query treats the user's -- selections as a single variable called @Properties. -- Example scenario 1: User only wants to see Elements that are BOTH Red and Dense. select e.* from Elements e where (@Properties) --ideally a set containing only Red and Dense in (select Text from #masterTable where ElementId = e.Id) --ideally a set containing only Red, Coarse, and Dense --Both Red and Dense are within Element 1's properties (Red, Coarse, Dense), so Element 1 gets returned, but not Element 2. -- Example scenario 2: User only wants to see Elements that are BOTH Red and Hollow. select e.* from Elements e where (@Properties) --ideally a set containing only Red and Hollow in (select Text from #masterTable where ElementId = e.Id) --Both Red and Hollow are within Element 2's properties (Red, Smooth, Hollow), so Element 2 gets returned, but not Element 1. --Example Scenario 3: User only picked the Red option. select e.* from Elements e where (@Properties) --ideally a set containing only Red in (select Text from #masterTable where ElementId = e.Id) --Red is within both Element 1 and Element 2's properties, so both Element 1 and Element 2 get returned. The above syntax doesn't actually work because SQL doesn't seem to allow multiple values on the left side of the "in" comparison. Error that returns: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. Am I even on the right track here? Sorry if the example looks long-winded or confusing.

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  • Programmatically created GridView cells don't scale to fit screen

    - by ChrisAshton84
    I've read a ton of other responses about GridView already but almost all deal with the XML format (which I had working). I wanted to learn the programmatic way of designing Android, though, so I'm trying to build most of this app without XML. All I define in XML are the GridView and the first TextView. After that I add the other LinearLayouts in onCreate(). I would like to have a 2 column GridView containing a title and several (4 for now) LinearLayouts. I realize from documentation that the GridView won't scale cells unless they have a gravity set, but no matter how I try to do this I can't get it to work. After adding two cells, my GridView tree would look like: GridView -> TextView (colspan 2) -> LinearLayout (Vertical) -> TextView -> LinearLayout (Horizontal) -> TextView -> TextView -> LinearLayout (Horizontal) -> TextView -> TextView -> LinearLayout (Vertical) -> TextView -> LinearLayout (Horizontal) -> TextView -> TextView -> LinearLayout (Horizontal) -> TextView -> TextView I've tried about every combination of FILL and FILL_HORIZONTAL I could think of on either the outermost LinearLayouts, or also trying on the TextViews and inner LinearLayouts. No matter what I do, the LinearLayouts I add are always sized as small as possible and pushed to the left of the screen. Meanwhile, the first TextView (the colspan 2 one) with only CENTER_HORIZONTAL set is correctly centered in the screen. Its as if that TextView gets one idea of the column widths and the LinearLayouts get another! (If I add the FILL Gravity for it, it also moves all the way left.) I believe I had this working accidentally with 100% XML, but I would prefer not to switch back unless this is known to not work programatically. Any ideas what I can try to get this working?

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  • Trouble passing a string as a SQLite ExecSQL command

    - by Hackbrew
    I keep getting the ERROR: near "PassWord": syntax error when trying to execute the ExecSQL() statement. The command looks good in the output of the text file. In fact, I copied & pasted the command directly into SQLite Database Browser and the commend executed properly. Here's the code that's producing the error: procedure TForm1.Button1Click(Sender: TObject); var i, iFieldSize: integer; sFieldName, sFieldType, sFieldList, sExecSQL: String; names: TStringList; f1: Textfile; begin //Open Source table - Table1 has 8 fields but has only two different field types ftString and Boolean Table1.TableName:= 'PWFile'; Table1.Open; //FDConnection1.ExecSQL('drop table PWFile'); sFieldList := ''; names := TStringList.Create; for i := 0 to Table1.FieldCount - 1 do begin sFieldName := Table1.FieldDefList.FieldDefs[i].Name; sFieldType := GetEnumName(TypeInfo(TFieldType),ord(Table1.FieldDefList.FieldDefs[i].DataType)); iFieldSize := Table1.FieldDefList.FieldDefs[i].Size; if sFieldType = 'ftString' then sFieldType := 'NVARCHAR' + '(' + IntToStr(iFieldSize) + ')'; if sFieldType = 'ftBoolean' then sFieldType := 'INTEGER'; names.Add(sFieldName + ' ' + sFieldType); if sFieldList = '' then sFieldList := sFieldName + ' ' + sFieldType else sFieldList := sFieldList + ', ' + sFieldName + ' ' + sFieldType; end; ListBox1.Items.Add(sFieldList); sExecSQL := 'create table IF NOT EXISTS PWFile (' + sFieldList + ')'; // 08/18/2014 - Entered this to log the SQLite FDConnection1.ExecSQL Command to a file AssignFile(f1, 'C:\Users\Test User\Documents\SQLite_Command.txt'); Rewrite(f1); Writeln(f1, sExecSQL); { insert code here that would require a Flush before closing the file } Flush(f1); { ensures that the text was actually written to file } CloseFile(f1); FDConnection1.ExecSQL(sFieldList); Table1.Close; end; Here's the actual command that gets executed: create table IF NOT EXISTS PWFile (PassWord NVARCHAR(10), PassName NVARCHAR(10), Dept NVARCHAR(10), Active NVARCHAR(1), Admin INTEGER, Shred INTEGER, Reports INTEGER, Maintain INTEGER)

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  • Is a Multi-DAL Approach the way to go here?

    - by Krisc
    Working on the data access / model layer in this little MVC2 project and trying to think things out to future projects. I have a database with some basic tables and I have classes in the model layer that represent them. I obviously need something to connect the two. The easiest is to provide some sort of 'provider' that can run operations on the database and return objects. But this is for a website that would potentially be used "a lot" (I know, very general) so I want to cache results from the data layer and keep the cache updated as new data is generated. This question deals with how best to approach this problem of dual DALS. One that returns cached data when possible and goes to the data layer when there is a cache miss. But more importantly, how to integrate the core provider (thing that goes into database) with the caching layer so that it too can rely on cached objects rather than creating new ones. Right now I have the following interfaces: IDataProvider is used to reach the database. It doesn't concern itself with the meaning of the objects it produces, but simply the way to produce them. interface IDataProvider{ // Select, Update, Create, et cetera access IEnumerable<Entry> GetEntries(); Entry GetEntryById(int id); } IDataManager is a layer that sits on top of the IDataProvider layer and manages the cache interface IDataManager : IDataProvider{ void ClearCache(); } Note that in practice the IDataManager implementation will have useful helper functions to add objects to their related cache stores. (In the future I may define other functions on the interface) I guess what I am looking for is the best way to approach a loop back from the IDataProvider implementations so that they can access the cache. Or a different approach entirely may be in order? I am not very interested in 3rd party products at the moment as I am interested in the design of these things much more than this specific implementation. Edit: I realize the title may be a bit misleading. I apologize for that... not sure what to call this question.

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  • Any way to allow classes implementing IEntity and downcast to have operator == comparisons?

    - by George Mauer
    Basically here's the issue. All entities in my system are identified by their type and their id. new Customer() { Id = 1} == new Customer() {Id = 1}; new Customer() { Id = 1} != new Customer() {Id = 2}; new Customer() { Id = 1} != new Product() {Id = 1}; Pretty standard scenario. Since all Entities have an Id I define an interface for all entities. public interface IEntity { int Id { get; set;} } And to simplify creation of entities I make public abstract class BaseEntity<T> : where T : IEntity { int Id { get; set;} public static bool operator ==(BaseEntity<T> e1, BaseEntity<T> e2) { if (object.ReferenceEquals(null, e1)) return false; return e1.Equals(e2); } public static bool operator !=(BaseEntity<T> e1, BaseEntity<T> e2) { return !(e1 == e2); } } where Customer and Product are something like public class Customer : BaseEntity<Customer>, IEntity {} public class Product : BaseEntity<Product>, IEntity {} I think this is hunky dory. I think all I have to do is override Equals in each entity (if I'm super clever, I can even override it only once in the BaseEntity) and everything with work. So now I'm expanding my test coverage and find that its not quite so simple! First of all , when downcasting to IEntity and using == the BaseEntity< override is not used. So what's the solution? Is there something else I can do? If not, this is seriously annoying. Upadate It would seem that there is something wrong with my tests - or rather with comparing on generics. Check this out [Test] public void when_created_manually_non_generic() { // PASSES! var e1 = new Terminal() {Id = 1}; var e2 = new Terminal() {Id = 1}; Assert.IsTrue(e1 == e2); } [Test] public void when_created_manually_generic() { // FAILS! GenericCompare(new Terminal() { Id = 1 }, new Terminal() { Id = 1 }); } private void GenericCompare<T>(T e1, T e2) where T : class, IEntity { Assert.IsTrue(e1 == e2); } Whats going on here? This is not as big a problem as I was afraid, but is still quite annoying and a completely unintuitive way for the language to behave. Update Update Ah I get it, the generic implicitly downcasts to IEntity for some reason. I stand by this being unintuitive and potentially problematic for my Domain's consumers as they need to remember that anything happening within a generic method or class needs to be compared with Equals()

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  • Correct usage of socket_select().

    - by Mark Tomlin
    What is the correct way to use socket_select within PHP to send and receive data? I have a connection to the server that allows for both TCP & UDP packet connections, I am utilizing both. Within these connections I'm both sending and receiving packets on the same port, but the TCP packet will be sent on one port (29999) and UDP will be sent on another port (30000). The transmission type will be that of AF_INET. The IP address will be loopback 127.0.0.1. I have many questions on how to create a socket connection within this scenario. For example, is it better to use socket_create_pair to make the connection, or use just socket_create followed by socket_connect, and then implement socket_select? There is a chance that no data will be sent from the server to the client, and it is up to the client to maintain the connection. This will be done by utilizing the time out function within the socket_select call. Should no data be sent within the time limit, the socket_select function will break and a keep alive packet can then be sent. The following script is of the client. // Create $TCP = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); $UDP = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP); // Misc $isAlive = TRUE; $UDPPort = 30000; define('ISP_ISI', 1); // Connect socket_connect($TCP, '127.0.0.1', 29999); socket_connect($UDP, '127.0.0.1', $UDPPort); // Construct Parameters $recv = array($TCP, $UDP); $null = NULL; // Make The Packet to Send. $packet = pack('CCCxSSxCSa16a16', 44, ISP_ISI, 1, $UDPPort, 0, '!', 0, 'AdminPass', 'SocketSelect'); // Send ISI (InSim Init) Packet socket_write($TCP, $packet); /* Main Program Loop */ while ($isAlive == TRUE) { // Socket Select $sock = socket_select($recv, $null, $null, 5); // Check Status if ($sock === FALSE) $isAlive = FALSE; # Error else if ($sock > 0) # How does one check to find what socket changed? else # Something else happed, don't know what as it's not in the documentation, Could this be our timeout getting tripped? }

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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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  • Problem separating C++ code in header, inline functions and code.

    - by YuppieNetworking
    Hello all, I have the simplest code that I want to separate in three files: Header file: class and struct declarations. No implementations at all. Inline functions file: implementation of inline methods in header. Code file: normal C++ code for more complicated implementations. When I was about to implement an operator[] method, I couldn't manage to compile it. Here is a minimal example that shows the same problem: Header (myclass.h): #ifndef _MYCLASS_H_ #define _MYCLASS_H_ class MyClass { public: MyClass(const int n); virtual ~MyClass(); double& operator[](const int i); double operator[](const int i) const; void someBigMethod(); private: double* arr; }; #endif /* _MYCLASS_H_ */ Inline functions (myclass-inl.h): #include "myclass.h" inline double& MyClass::operator[](const int i) { return arr[i]; } inline double MyClass::operator[](const int i) const { return arr[i]; } Code (myclass.cpp): #include "myclass.h" #include "myclass-inl.h" #include <iostream> inline MyClass::MyClass(const int n) { arr = new double[n]; } inline MyClass::~MyClass() { delete[] arr; } void MyClass::someBigMethod() { std::cout << "Hello big method that is not inlined" << std::endl; } And finally, a main to test it all: #include "myclass.h" #include <iostream> using namespace std; int main(int argc, char *argv[]) { MyClass m(123); double x = m[1]; m[1] = 1234; cout << "m[1]=" << m[1] << endl; x = x + 1; return 0; } void nothing() { cout << "hello world" << endl; } When I compile it, it says: main.cpp:(.text+0x1b): undefined reference to 'MyClass::MyClass(int)' main.cpp:(.text+0x2f): undefined reference to 'MyClass::operator[](int)' main.cpp:(.text+0x49): undefined reference to 'MyClass::operator[](int)' main.cpp:(.text+0x65): undefined reference to 'MyClass::operator[](int)' However, when I move the main method to the MyClass.cpp file, it works. Could you guys help me spot the problem? Thank you.

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