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  • How to clean and simplify this code?

    - by alkalim
    After thinking about This Question and giving an answer to it I wanted to do more about that to train myself. So I wrote a function which will calc the length of an given function. Th given php-file has to start at the beginning of the needed function. Example: If the function is in a big phpfile with lots of functions, like /* lots of functions */ function f_interesting($arg) { /* function */ } /* lots of other functions */ then $part3 of my function will require to begin like that (after the starting-{ of the interesting function): /* function */ } /* lots of other functions */ Now that's not the problem, but I would like to know if there are an cleaner or simplier ways to do this. Here's my function: (I already cleaned a lot of testing-echo-commands) (The idea behind it is explained here) function f_analysis ($part3) { if(isset($part3)) { $char_array = str_split($part3); //get array of chars $end_key = false; //length of function $depth = 0; //How much of unclosed '{' $in_sstr = false; //is next char inside in ''-String? $in_dstr = false; //is nect char inside an ""-String? $in_sl_comment = false; //inside an //-comment? $in_ml_comment = false; //inside an /* */-comment? $may_comment = false; //was the last char an '/' which can start a comment? $may_ml_comment_end = false; //was the last char an '*' which may end a /**/-comment? foreach($char_array as $key=>$char) { if($in_sstr) { if ($char == "'") { $in_sstr = false; } } else if($in_dstr) { if($char == '"') { $in_dstr = false; } } else if($in_sl_comment) { if($char == "\n") { $in_sl_comment = false; } } else if($in_ml_comment) { if($may_ml_comment_end) { $may_ml_comment_end = false; if($char == '/') { $in_ml_comment = false; } } if($char == '*') { $may_ml_comment_end = true; } } else if ($may_comment) { if($char == '/') { $in_sl_comment = true; } else if($char == '*') { $in_ml_comment = true; } $may_comment = false; } else { switch ($char) { case '{': $depth++; break; case '}': $depth--; break; case '/': $may_comment = true; break; case '"': $in_dstr = true; break; case "'": $in_sstr = true; break; } } if($depth < 0) { $last_key = $key; break; } } } else echo '<br>$part3 of f_analysis not set!'; return ($last_key===false) ? false : $last_key+1; //will be false or the length of the function }

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  • how to solve ran time error NSString, sqlite3_column_text NULL problem?

    - by Ajeet Kumar Yadav
    I am new in iphone application developer i am using sqlite3 database and in app delegate i am wright following code and run properly we also find value from database to in my aplication, but immediately the application is going to crass why this is occurs i am not understand. code is given bellow -(void)Data { databaseName = @"dataa.sqlite"; NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDir = [documentPaths objectAtIndex:0]; databasePath =[documentsDir stringByAppendingPathComponent:databaseName]; [self checkAndCreateDatabase]; list1 = [[NSMutableArray alloc] init]; sqlite3 *database; if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { if(detailStmt == nil) { const char *sql = "Select * from Dataa"; if(sqlite3_prepare_v2(database, sql, -1, &detailStmt, NULL) == SQLITE_OK) { //NSLog(@"Hiiiiiii"); //sqlite3_bind_text(detailStmt, 1, [t1 UTF8String], -1, SQLITE_TRANSIENT); //sqlite3_bind_text(detailStmt, 2, [t2 UTF8String], -2, SQLITE_TRANSIENT); //sqlite3_bind_int(detailStmt, 3, t3); while(sqlite3_step(detailStmt) == SQLITE_ROW) { //NSLog(@"Helllloooooo"); NSString *item= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 0)]; //NSString *fame= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 1)]; //NSString *cinemax = [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 2)]; //NSString *big= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 3)]; //pvr1 = pvr; item1=item; //NSLog(@"%@",item1); data = [[NSMutableArray alloc] init]; list *animal=[[list alloc] initWithName:item1]; // Add the animal object to the animals Array [list1 addObject:animal]; //[list1 addObject:item]; } sqlite3_reset(detailStmt); } sqlite3_finalize(detailStmt); // sqlite3_clear_bindings(detailStmt); } } detailStmt = nil; sqlite3_close(database); } when we see console they show the following error giving bellow 2010-03-09 10:02:40.262 SanjeevKapoor[430:20b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** +[NSString stringWithUTF8String:]: NULL cString' when we see debugger they show error in following line NSString *item= [NSString stringWithUTF8String:(char *)sqlite3_column_text(detailStmt, 0)]; I am not able to solve that problum plz help me.

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  • Mootools 1.2.4 delegation not working in IE8...?

    - by michael
    Hey there everybody-- So I have a listbox next to a form. When the user clicks an option in the select box, I make a request for the related data, returned in a JSON object, which gets put into the form elements. When the form is saved, the request goes thru and the listbox is rebuilt with the updated data. Since it's being rebuilt I'm trying to use delegation on the listbox's parent div for the onchange code. The trouble I'm having is with IE8 (big shock) not firing the delegated event. I have the following HTML: <div id="listwrapper" class="span-10 append-1 last"> <select id="list" name="list" size="20"> <option value="86">Adrian Franklin</option> <option value="16">Adrian McCorvey</option> <option value="196">Virginia Thomas</option> </select> </div> and the following script to go with it: window.addEvent('domready', function() { var jsonreq = new Request.JSON(); $('listwrapper').addEvent('change:relay(select)', function(e) { alert('this doesn't fire in IE8'); e.stop(); var status= $('statuswrapper').empty().addClass('ajax-loading'); jsonreq.options.url = 'de_getformdata.php'; jsonreq.options.method = 'post'; jsonreq.options.data = {'getlist':'<?php echo $getlist ?>','pkey':$('list').value}; jsonreq.onSuccess = function(rObj, rTxt) { status.removeClass('ajax-loading'); for (key in rObj) { status.set('html','You are currently editing '+rObj['cname']); if ($chk($(key))) $(key).value = rObj[key]; } $('lalsoaccomp-yes').set('checked',(($('naccompkey').value > 0)?'true':'false')); $('lalsoaccomp-no').set('checked',(($('naccompkey').value > 0)?'false':'true')); } jsonreq.send(); }); }); (I took out a bit of unrelated stuff). So this all works as expected in firefox, but IE8 refuses to fire the delegated change event on the select element. If I attach the change function directly to the select, then it works just fine. Am I missing something? Does IE8 just not like the :relay? Sidenote: I'm very new to mootools and javascripting, etc, so if there's something that can be improved code-wise, please let me know too.. Thanks!

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  • Go - Using a container/heap to implement a priority queue

    - by Seth Hoenig
    In the big picture, I'm trying to implement Dijkstra's algorithm using a priority queue. According to members of golang-nuts, the idiomatic way to do this in Go is to use the heap interface with a custom underlying data structure. So I have created Node.go and PQueue.go like so: //Node.go package pqueue type Node struct { row int col int myVal int sumVal int } func (n *Node) Init(r, c, mv, sv int) { n.row = r n.col = c n.myVal = mv n.sumVal = sv } func (n *Node) Equals(o *Node) bool { return n.row == o.row && n.col == o.col } And PQueue.go: // PQueue.go package pqueue import "container/vector" import "container/heap" type PQueue struct { data vector.Vector size int } func (pq *PQueue) Init() { heap.Init(pq) } func (pq *PQueue) IsEmpty() bool { return pq.size == 0 } func (pq *PQueue) Push(i interface{}) { heap.Push(pq, i) pq.size++ } func (pq *PQueue) Pop() interface{} { pq.size-- return heap.Pop(pq) } func (pq *PQueue) Len() int { return pq.size } func (pq *PQueue) Less(i, j int) bool { I := pq.data.At(i).(Node) J := pq.data.At(j).(Node) return (I.sumVal + I.myVal) < (J.sumVal + J.myVal) } func (pq *PQueue) Swap(i, j int) { temp := pq.data.At(i).(Node) pq.data.Set(i, pq.data.At(j).(Node)) pq.data.Set(j, temp) } And main.go: (the action is in SolveMatrix) // Euler 81 package main import "fmt" import "io/ioutil" import "strings" import "strconv" import "./pqueue" const MATSIZE = 5 const MATNAME = "matrix_small.txt" func main() { var matrix [MATSIZE][MATSIZE]int contents, err := ioutil.ReadFile(MATNAME) if err != nil { panic("FILE IO ERROR!") } inFileStr := string(contents) byrows := strings.Split(inFileStr, "\n", -1) for row := 0; row < MATSIZE; row++ { byrows[row] = (byrows[row])[0 : len(byrows[row])-1] bycols := strings.Split(byrows[row], ",", -1) for col := 0; col < MATSIZE; col++ { matrix[row][col], _ = strconv.Atoi(bycols[col]) } } PrintMatrix(matrix) sum, len := SolveMatrix(matrix) fmt.Printf("len: %d, sum: %d\n", len, sum) } func PrintMatrix(mat [MATSIZE][MATSIZE]int) { for r := 0; r < MATSIZE; r++ { for c := 0; c < MATSIZE; c++ { fmt.Printf("%d ", mat[r][c]) } fmt.Print("\n") } } func SolveMatrix(mat [MATSIZE][MATSIZE]int) (int, int) { var PQ pqueue.PQueue var firstNode pqueue.Node var endNode pqueue.Node msm1 := MATSIZE - 1 firstNode.Init(0, 0, mat[0][0], 0) endNode.Init(msm1, msm1, mat[msm1][msm1], 0) if PQ.IsEmpty() { // make compiler stfu about unused variable fmt.Print("empty") } PQ.Push(firstNode) // problem return 0, 0 } The problem is, upon compiling i get the error message: [~/Code/Euler/81] $ make 6g -o pqueue.6 Node.go PQueue.go 6g main.go main.go:58: implicit assignment of unexported field 'row' of pqueue.Node in function argument make: *** [all] Error 1 And commenting out the line PQ.Push(firstNode) does satisfy the compiler. But I don't understand why I'm getting the error message in the first place. Push doesn't modify the argument in any way.

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  • Using pointers, references, handles to generic datatypes, as generic and flexible as possible

    - by Patrick
    In my application I have lots of different data types, e.g. Car, Bicycle, Person, ... (they're actually other data types, but this is just for the example). Since I also have quite some 'generic' code in my application, and the application was originally written in C, pointers to Car, Bicycle, Person, ... are often passed as void-pointers to these generic modules, together with an identification of the type, like this: Car myCar; ShowNiceDialog ((void *)&myCar, DATATYPE_CAR); The 'ShowNiceDialog' method now uses meta-information (functions that map DATATYPE_CAR to interfaces to get the actual data out of Car) to get information of the car, based on the given data type. That way, the generic logic only has to be written once, and not every time again for every new data type. Of course, in C++ you could make this much easier by using a common root class, like this class RootClass { public: string getName() const = 0; }; class Car : public RootClass { ... }; void ShowNiceDialog (RootClass *root); The problem is that in some cases, we don't want to store the data type in a class, but in a totally different format to save memory. In some cases we have hundreds of millions of instances that we need to manage in the application, and we don't want to make a full class for every instance. Suppose we have a data type with 2 characteristics: A quantity (double, 8 bytes) A boolean (1 byte) Although we only need 9 bytes to store this information, putting it in a class means that we need at least 16 bytes (because of the padding), and with the v-pointer we possibly even need 24 bytes. For hundreds of millions of instances, every byte counts (I have a 64-bit variant of the application and in some cases it needs 6 GB of memory). The void-pointer approach has the advantage that we can almost encode anything in a void-pointer and decide how to use it if we want information from it (use it as a real pointer, as an index, ...), but at the cost of type-safety. Templated solutions don't help since the generic logic forms quite a big part of the application, and we don't want to templatize all this. Additionally, the data model can be extended at run time, which also means that templates won't help. Are there better (and type-safer) ways to handle this than a void-pointer? Any references to frameworks, whitepapers, research material regarding this?

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  • Using empty row as default in a ComboBox with Style "DropDownList"?

    - by Pesche Helfer
    Hi board I am trying to write a method, that takes a ComboBox, a DataTable and a TextBox as arguments. The purpose of it is to filter the members displayed in the ComboBox according to the TextBox.Text. The DataTable contains the entire list of possible entries that will then be filtered. For filtering, I create a DataView of the DataTable, add a RowFilter and then bind this View to the ComboBox as DataSource. To prevent the user from typing into the ComboBox, I choose the DropDownStyle DropDownList. That’s working fine so far, except that the user should also be able to choose nothing / empty line. In fact, this should be the default member to be displayed (to prevent choosing a wrong member by accident, if the user clicks through the dialog too fast). I tried to solve this problem by adding a new Row to the view. While this works for some cases, the main issue here is that any DataTable can be passed to the method. If the DataTable contains columns that cannot be null and don’t contain a default value, I suppose I will raise an error by adding an empty row. A possibility would be to create a view that contains only the column that is defined as DisplayMember, and the one that is defined as ValueMember. Alas, this can’t be done with a view in C#. I would like to avoid creating a true copy of the DataTable at all cost, since who knows how big it will get with time. Do you have any suggestions how to get around this problem? Instead of a view, could I create an object containing two members and assign the DisplayMember and the ValueMember to these members? Would the members be passed as reference (what I hope) or would true copied be created (in which case it would not be a solution)? Thank you very much for your help! Best regards public static void ComboFilter(ComboBox cb, DataTable dtSource, TextBox filterTextBox) { cb.DropDownStyle = ComboBoxStyle.DropDownList; string displayMember = cb.DisplayMember; DataView filterView = new DataView(dtSource); filterView.AddNew(); filterView.RowFilter = displayMember + " LIKE '%" + filterTextBox.Text + "%'"; cb.DataSource = filterView; }

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  • What would you suggest as a high school first language?

    - by ldigas
    Edit by OA: After reading some answers I'll just update the question a little. At first I put it a little bluntly, but some of those gave me some good arguments which have to be taken into consideration while making a stand on this one. (these are mostly picked up from comments and answers below). A few things to take into account: to many pupils this is a first programming language - at this stage most of them have trouble grasping a difference between data types, variable passing, ... and whatnot, less alone pointers and similar 'low level stuff' :) they will all have to pass this to get into next grade (well, big majority of them anyway) not all of them have computers at home, not all of them are willing to learn this, less alone interested in - so the concepts have to be taught on a finite time scale in school hours (as well as practice on computers) free literature is a bonus - the teacher will make some scripts and handaways, but still ... I wouldn't like to bear the parents with the burden of buying expensive literature (also, english is not a native language here ... and although they are all learning it, their ability to read it fluently is somewhat questionable) somebody gave an argument - "a language which does not get in the way of ideas" - good one accessibility on different platforms in not expecially important at this point - although most of the suggested ones are available on win as well as linux - not many macs in this part of europe (their prices are sky high for anything but specialised usage) I will check what are the licencing issues on ms express editions about using it massively in high schools for purposes like this - if someone has any info about this, please, do not be shy with it :) A friend of mine, informatics teacher - in EU it comes as something as junior cs teacher, in a local high school asked me what I thought about what should be the first language pupils should be taught? It is a technical school (a little more oriented towards mathematics than the gymnasium, but not computer oriented totally). So I'm asking you - what do you think should be the first language pupils are exposed to in highschool? They have been teaching Pascal so far, but she's not sure that's a good course. She thought about switching to C (which I resented; considering not all pupils have interests in programming, to start with, and should be taught something higher level since they are just gripping the idea of a loop and such ... for a start), I suggested python or ruby (preferably py since it handles all paradigms). What is your opinion on this one? I looked, but didn't find a similar question on SO, so if there is one, please just point me towards it. Edit: The assumption is that none of the pupils have been exposed to any programming in junior school. See also: What is the best way to teach young kids some basic programming concepts? Best ways to teach a beginner to program How and when do you teach a kid to code What is the easiest language to start with? High School Programming

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  • How can I create the XML::Simple data structure using a Perl XML SAX parser?

    - by DVK
    Summary: I am looking a fast XML parser (most likely a wrapper around some standard SAX parser) which will produce per-record data structure 100% identical to those produced by XML::Simple. Details: We have a large code infrastructure which depends on processing records one-by-one and expects the record to be a data structure in a format produced by XML::Simple since it always used XML::Simple since early Jurassic era. An example simple XML is: <root> <rec><f1>v1</f1><f2>v2</f2></rec> <rec><f1>v1b</f1><f2>v2b</f2></rec> <rec><f1>v1c</f1><f2>v2c</f2></rec> </root> And example rough code is: sub process_record { my ($obj, $record_hash) = @_; # do_stuff } my $records = XML::Simple->XMLin(@args)->{root}; foreach my $record (@$records) { $obj->process_record($record) }; As everyone knows XML::Simple is, well, simple. And more importantly, it is very slow and a memory hog—due to being a DOM parser and needing to build/store 100% of data in memory. So, it's not the best tool for parsing an XML file consisting of large amount of small records record-by-record. However, re-writing the entire code (which consist of large amount of "process_record"-like methods) to work with standard SAX parser seems like an big task not worth the resources, even at the cost of living with XML::Simple. I'm looking for an existing module which will probably be based on a SAX parser (or anything fast with small memory footprint) which can be used to produce $record hashrefs one by one based on the XML pictured above that can be passed to $obj->process_record($record) and be 100% identical to what XML::Simple's hashrefs would have been. I don't care much what the interface of the new module is; e.g whether I need to call next_record() or give it a callback coderef accepting a record.

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  • How to remove the explicit dependencies to other projects' libraries in Eclipse launch configuration

    - by euluis
    In Eclipse it is possible to create launch configurations in a project, specifying the runtime dependencies from another project. A problem I found was that if you have a multiple project workspace, being possible that each project has its own libraries, it is easy to add explicit dependencies in a secondary project to libraries that are of another project and therefore subject to change. An example of this problem follows: proj1 +-- src +-- lib +-- jar1-v1.0.jar +-- jar2-v1.0.jar proj2 +-- src +-- proj2-tests.launch I don't have a dependency from the code in proj2/src to the libraries in proj1/lib. Nevertheless, I do have a dependency from proj2/src to proj1/src, although since there is an internal dependency in the code in proj1/src to its libraries jar1-v1.0.jar and jar2.v1.0.jar, I have to add a dependency in proj2-tests.launch to the libraries in proj1/lib. This translates to the following ugly lines in proj2-tests.launch: <listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?> <runtimeClasspathEntry path="3" projectName="proj1" type="1"/> "/> <listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?> <runtimeClasspathEntry internalArchive="/proj1/lib/jar1-v1.0.jar" path="3" type="2"/> "/> <listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?> <runtimeClasspathEntry internalArchive="/proj1/lib/jar2-v1.0.jar" path="3" type="2"/> "/> This wouldn't be a big problem if there wasn't the need from time to time to evolve the software, upgrade the libraries and etc. Consider the common need to upgrade the libraries jar1-v1.0.jar and jar2-v1.0.jar to their versions v1.1. Consider that you have about 10 projects in one workspace, having about 5 libraries each and about 4 launch configurations. You get a maintenance overhead in doing a simple upgrade of a library, which normally must imply changes in files for which there wasn't the need for. Or maybe I'm doing something wrong... What I would like to state is proj2 depends on proj1 and on its libraries and having this translated to simply that in the *.launch files. Is that possible?

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  • javascript works with mozilla but not with webkit based browsers

    - by GlassGhost
    Im having problems with a css text variable in this javascript with webkit based browsers(Chrome & Safari) but it works in firefox 3.6 importScript('User:Gerbrant/hidePane.js');//Special thanks to Gerbrant for this wonderful script function addGlobalStyle(css) { var head = document.getElementsByTagName('head')[0]; if (!head) { return; } var style = document.createElement('style'); style.type = 'text/css'; style.rel = 'stylesheet'; style.media = 'screen'; style.href = 'FireFox.css'; style.innerHTML = css; head.appendChild(style); } //The page styling var NewSyleText = "h1, h2, h3, h4, h5 {font-family: 'Verdana','Helvetica',sans-serif; font-style: normal; font-weight:normal;}" + "body, b {background: #fbfbfb; font-style: normal; font-family: 'Cochin','GaramondNo8','Garamond','Big Caslon','Georgia','Times',serif;font-size: 11pt;}" + "p { margin: 0pt; text-indent:1.25em; margin-top: 0.3em; }" + "a { text-decoration: none; color: Navy; background: none;}" + "a:visited { color: #500050;}" + "a:active { color: #faa700;}" + "a:hover { text-decoration: underline;}" + "a.stub { color: #772233;}" + "a.new, #p-personal a.new { color: #ba0000;}" + "a.new:visited, #p-personal a.new:visited { color: #a55858;}" + "a.new, #quickbar a.new { color: #CC2200; }" + /* removes "From Wikipedia, the free encyclopedia" for those of you who actually know what site you are on */ "#siteSub { display: none; }" + /* hides the speaker icon in some articles */ "#spoken-icon .image { display:none;}" + /* KHTMLFix.css */ "#column-content { margin-left: 0; }" + /* Remove contents of the footer, but not the footer itself */ "#f-poweredbyico, #f-copyrightico { display:none;}" + /* Needed to show the star icon in a featured article correctly */ "#featured-star div div { line-height: 10px;}" + /* And the content expands to top and left */ "#content {margin: 0; padding: 0; background:none;}" + "#content div.thumb {border-color:white;}" + /* Hiding the bar under the entry header */ "h1.firstHeading { border-bottom: none;}" + /* Used for US city entries */ "#coordinates { top:1.2em;}"; addGlobalStyle(NewSyleText);//inserts the page styling

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  • Grid sorting with persistent master sort

    - by MikeWyatt
    I have a UI with a grid. Each record in the grid is sorted by a "master" sort column, let's call it a page number. Each record is a story in a magazine. I want the user to be able to drag and drop a record to a new position in the grid and automatically update the page number field to reflect the updated position. Easy enough, right? Now imagine that I also want to have the grid sortable by any other column (story title, section, author name, etc.). How does the drag and drop operation work now? Revert to page number sort during or after the drag and drop operation? This could confuse the user (why did my sort just change?). It would also result in arbitrary row positioning. Would the story now be before the row that was after it when the user dropped it? Or, would it be after the row that was before it? Those rows may now be widely separated after the master order sort. Disable the drag and drop feature if the grid isn't currently sorted by the page number? This would be easy, but the user might wonder why he can't drag and drop at certain times. Knowing to first sort by page number may not be very intuitive. Let the user rearrange his rows, but not make any changes to the page number? Require the user to enter a "Arrange Stories" mode, in which the grid sort is temporarily switched to page number and drag and drop is enabled? They would then exit the mode, and the previous sort would be reapplied. The big difference between this and the second option is that it would be more explicit than simply clicking on a column header. Any other ideas, or reasons why one of the above is the way to go? EDIT I'd like to point out that any of the above is technically possible, and easy to implement. My question is design-related. What is the most intuitive way to solve this problem, from the user's perspective?

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  • Learn C# now or finish up with Java and then learn C#?

    - by Sahat
    Ok here is my situation. I've studied Java in my college for 2 semesters. But you know they teach you jack in there, just the basics. We skipped half of our textbook and even then our professors don't teach from section to section of each chapter. I don't blame them. It's hard as it is for new students to understand even the basic concepts of programming. Now this is a community college we are talking about and not Stanford, MIT or Berkeley. So like I said I've done 2 semester of Java. I really like our textbook because it has some challenging projects to do at the end of each chapter. This textbook is pretty clear and i have no problem understanding it (although 2-D and 3-D Arrays have given me some trouble). I have tried reading a few C# books such as Pro C# 2008 and .NET 3.5 and C# 4.0 in a Nutshell. I found these books to be dry and overloaded with information that put me to sleep (No offense to the authors of those 2 wonderful, according to amazon ratings, books). Would you suggest I finish my Java textbook, brush up my knowledge of Arrays, Polymorphism, and etc that are universal to most programming languages. And then switch to C#, plus the syntax is very similar so it should be easy to switch. Or should I just start learning C# right now from the very beginning? If it's the latter then could you recommend some free online resources that will keep me engaged and at the same time teach me everything I need to know about C#. Someone has recommended me to learn .NET first, but I found it to be not the brightest idea. .NET is just a big monster full of libraries. How am I going to apply it if I don't even know the C# or VB!? Anyway back to my question: Master Java and switch to C# or just go with C#? DISCLAIMER: I don't want to start .NET vs J2EE or C# vs Java flame war. I am going with C#. I've decided that I want to work in a Microsoft shop in the future. .NET is what I want to learn. Thanks! Will be waiting for the answers.

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  • Is there limit of "join" or the "where" or length of SQL query ?

    - by Chetan sharma
    Actually i was trying to get data from elgg database based on multiple joins. It generated very big query with lots of JOIN statements and query never respond back. SELECT distinct e.* from test_entities e JOIN test_metadata m1 on e.guid = m1.entity_guid JOIN test_metastrings ms1 on ms1.id = m1.name_id JOIN test_metastrings mv1 on mv1.id = m1.value_id JOIN test_objects_entity obj on e.guid = obj.guid JOIN test_metadata m2 on e.guid = m2.entity_guid JOIN test_metastrings ms2 on ms2.id = m2.name_id JOIN test_metastrings mv2 on mv2.id = m2.value_id JOIN test_metadata m3 on e.guid = m3.entity_guid JOIN test_metastrings ms3 on ms3.id = m3.name_id JOIN test_metastrings mv3 on mv3.id = m3.value_id JOIN test_metadata m4 on e.guid = m4.entity_guid JOIN test_metastrings ms4 on ms4.id = m4.name_id JOIN test_metastrings mv4 on mv4.id = m4.value_id JOIN test_metadata m5 on e.guid = m5.entity_guid JOIN test_metastrings ms5 on ms5.id = m5.name_id JOIN test_metastrings mv5 on mv5.id = m5.value_id JOIN test_metadata m6 on e.guid = m6.entity_guid JOIN test_metastrings ms6 on ms6.id = m6.name_id JOIN test_metastrings mv6 on mv6.id = m6.value_id where ms1.string='expire_date' and mv1.string <= 1272565800 and ms2.string='homecity' and mv2.string LIKE "%dasf%" and ms3.string='schoolname' and mv3.string LIKE "%asdf%" and ms4.string='award_amount' and mv4.string <= 123 and ms5.string='no_of_awards' and mv5.string <= 7 and ms6.string='avg_rating' and mv6.string <= 2 and e.type = 'object' and e.subtype = 5 and e.site_guid = 1 and (obj.title like '%asdf%') OR (obj.description like '%asdf%') and ( (e.access_id = -2 AND e.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (e.access_id IN (2,1) OR (e.owner_guid = 5) OR ( e.access_id = 0 AND e.owner_guid = 5 ) ) and e.enabled='yes') and ( (m1.access_id = -2 AND m1.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (m1.access_id IN (2,1) OR (m1.owner_guid = 5) OR ( m1.access_id = 0 AND m1.owner_guid = 5 ) ) and m1.enabled='yes') and ( (m2.access_id = -2 AND m2.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (m2.access_id IN (2,1) OR (m2.owner_guid = 5) OR ( m2.access_id = 0 AND m2.owner_guid = 5 ) ) and m2.enabled='yes') and ( (m3.access_id = -2 AND m3.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (m3.access_id IN (2,1) OR (m3.owner_guid = 5) OR ( m3.access_id = 0 AND m3.owner_guid = 5 ) ) and m3.enabled='yes') and ( (m4.access_id = -2 AND m4.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (m4.access_id IN (2,1) OR (m4.owner_guid = 5) OR ( m4.access_id = 0 AND m4.owner_guid = 5 ) ) and m4.enabled='yes') and ( (m5.access_id = -2 AND m5.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (m5.access_id IN (2,1) OR (m5.owner_guid = 5) OR ( m5.access_id = 0 AND m5.owner_guid = 5 ) ) and m5.enabled='yes') and ( (m6.access_id = -2 AND m6.owner_guid IN ( SELECT guid_one FROM test_entity_relationships WHERE relationship='friend' AND guid_two=5 )) OR (m6.access_id IN (2,1) OR (m6.owner_guid = 5) OR ( m6.access_id = 0 AND m6.owner_guid = 5 ) ) and m6.enabled='yes') order by obj.title limit 0, 10 this is the query that i am running.

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  • LinearLayout as custom button, OnClickListener never called

    - by ohra
    I've been using the common Android Button with both icon (drawableTop) and text. It works really poorly if you want to have a non-standard size button, so I decided to make a custom button with a LinearLayout having the following layout: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" style="@style/ButtonHoloDark" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center" android:clickable="true" android:focusable="true" android:orientation="vertical" > <ImageView android:id="@+id/buttonIcon" android:layout_width="fill_parent" android:layout_height="wrap_content" android:duplicateParentState="true" /> <TextView android:id="@+id/buttonText" android:layout_width="fill_parent" android:layout_height="wrap_content" android:duplicateParentState="true" android:gravity="center" android:textColor="@color/white" /> </LinearLayout> The layout is used by a custom class: public class CustomIconButton extends LinearLayout { public CustomIconButton(Context context, AttributeSet attrs) { super(context, attrs); setAttributes(context, attrs); LayoutInflater.from(context).inflate(R.layout.custom_icon_button, this, true); } ... But when I set an OnClickListener on my button in its parent layout it never gets called. I can only receive clicks if a set the listener to the ImageView and/or TextView. This leads to two possible effects when the button is clicked: The click is inside the ImageView or the TextView. The click is registered ok, but the buttons state drawable doesn't change i.e. it doesn't appear depressed. The click is inside the "empty area" of the button. The click is not registered, but the state drawable works ok. Neither of these is feasible. I've played around with the following attributes on the LinearLayout or its children, but none really seem to have any effect whether true or false: duplicateParentState clickable focusable There doesn't seem to be any reasonable way to get the LinearLayout parent receive clicks instead of its children. I've seen some possible solutions overriding dispatchTouchEvent or onInterceptTouchEvent on the custom component itself, but that really seems like a big mess if I have to start analyzing touch events to identify proper clicks. So OnClickListener on a LinearLayout with children = no go?

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  • Calling a function that resides in the main page from a plugin?

    - by Justin Lee
    I want to call a function from within plugin, but the function is on the main page and not the plugin's .js file. EDIT I have jQuery parsing a very large XML file and building, subsequently, a large list (1.1 MB HTML file when dynamic content is copied, pasted, then saved) that has expand/collapse functionality through a plugin. The overall performance on IE is super slow and doggy, assuming since the page/DOM is so big. I am currently trying to save the collapsed content in the event.data when it is collapsed and remove it from the DOM, then bring it back when it is told to expand... the issue that I am having is that when I bring the content back, obviously the "click" and "hover" events are gone. I'm trying to re-assign them, currently doing so inside the plugin after the plugin expands the content. The issue then though is that is says the function that I declare within the .click() is not defined. Also the hover event doesn't seem to be re-assigning either.... if ($(event.data.trigger).attr('class').indexOf('collapsed') != -1 ) { // if expanding // console.log(event.data.targetContent); $(event.data.trigger).after(event.data.targetContent); $(event.data.target).hide(); /* This Line --->*/ $(event.data.target + 'a.addButton').click(addResourceToList); $(event.data.target + 'li.resource') .hover( function() { if (!($(this).attr("disabled"))) { $(this).addClass("over"); $(this).find("a").css({'display':'block'}); } }, function () { if (!($(this).attr("disabled"))) { $(this).removeClass("over"); $(this).children("a").css({'display':'none'}); } } ); $(event.data.target).css({ "height": "0px", "padding-top": "0px", "padding-bottom": "0px", "margin-top": "0px", "margin-bottom": "0px"}); $(event.data.target).show(); $(event.data.target).animate({ height: event.data.heightVal + "px", paddingTop: event.data.topPaddingVal + "px", paddingBottom: event.data.bottomPaddingVal + "px", marginTop: event.data.topMarginVal + "px", marginBottom: event.data.bottomMarginVal + "px"}, "normal");//, function(){$(this).hide();}); $(event.data.trigger).removeClass("collapsed"); $.cookies.set('jcollapserSub_' + event.data.target, 'expanded', {hoursToLive: 24 * 365}); } else if ($(event.data.trigger).attr('class').indexOf('collapsed') == -1 ) { // if collapsing $(event.data.target).animate({ height: "0px", paddingTop: "0px", paddingBottom: "0px", marginTop: "0px", marginBottom: "0px"}, "normal", function(){$(this).hide();$(this).remove();}); $(event.data.trigger).addClass("collapsed"); $.cookies.set('jcollapserSub_' + event.data.target, 'collapsed', {hoursToLive: 24 * 365}); } EDIT So, having new eyes truly makes a difference. As I was reviewing the code in this post this morning after being away over the weekend, I found where I had err'd. This: $(event.data.target + 'a.addButton').click(addResourceToList); Should be this (notice the space before a.addbutton): $(event.data.target + ' a.addButton').click(addResourceToList); Same issue with the "li.resource". So it was never pointing to the right elements... Thank you, Rene, for your help!!

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  • Migrating from hand-written persistence layer to ORM

    - by Sergey Mikhanov
    Hi community, We are currently evaluating options for migrating from hand-written persistence layer to ORM. We have a bunch of legacy persistent objects (~200), that implement simple interface like this: interface JDBC { public long getId(); public void setId(long id); public void retrieve(); public void setDataSource(DataSource ds); } When retrieve() is called, object populates itself by issuing handwritten SQL queries to the connection provided using the ID it received in the setter (this usually is the only parameter to the query). It manages its statements, result sets, etc itself. Some of the objects have special flavors of retrive() method, like retrieveByName(), in this case a different SQL is issued. Queries could be quite complex, we often join several tables to populate the sets representing relations to other objects, sometimes join queries are issued on-demand in the specific getter (lazy loading). So basically, we have implemented most of the ORM's functionality manually. The reason for that was performance. We have very strong requirements for speed, and back in 2005 (when this code was written) performance tests has shown that none of mainstream ORMs were that fast as hand-written SQL. The problems we are facing now that make us think of ORM are: Most of the paths in this code are well-tested and are stable. However, some rarely-used code is prone to result set and connection leaks that are very hard to detect We are currently squeezing some additional performance by adding caching to our persistence layer and it's a huge pain to maintain the cached objects manually in this setup Support of this code when DB schema changes is a big problem. I am looking for an advice on what could be the best alternative for us. As far as I know, ORMs has advanced in last 5 years, so it might be that now there's one that offers an acceptable performance. As I see this issue, we need to address those points: Find some way to reuse at least some of the written SQL to express mappings Have the possibility to issue native SQL queries without the necessity to manually decompose their results (i.e. avoid manual rs.getInt(42) as they are very sensitive to schema changes) Add a non-intrusive caching layer Keep the performance figures. Is there any ORM framework you could recommend with regards to that?

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  • GLKit Memory Leak copywithZone

    - by TommyT39
    Running the instruments utility against the game I'm writing shows a bunch of memory leaks related to copy with Zone when I cycle through an array and draw some simple cube objects. Im not sure the best way to track this down as I'm new to OpenGL programming. My program is using ARC and is set to build for IOS 5. I am initializing GLKit to use OPenGl 2.0 and using the BafeEffect so I don't have to write my own shaders etc.. This shouldn't be rocket science. Im guessing that I must be not releasing something within the draw function. Below is the code to my draw function. Could you guys take a look and see if anything stands out as the problem? One other thing to note is that I'm using 15 different textures, the cubes can be 1 of 15 different ones. I have a property set on the cube class for the texture and I set it as I create the cube in there array. But I do load all 15 when my programs view did load starts.They are small .jps files that are less than 75k each and each cube uses the same texture all the way around so shouldn't be too big of an issue. Here is the code to my draw function: - (void)draw { GLKMatrix4 xRotationMatrix = GLKMatrix4MakeXRotation(rotation.x); GLKMatrix4 yRotationMatrix = GLKMatrix4MakeYRotation(rotation.y); GLKMatrix4 zRotationMatrix = GLKMatrix4MakeZRotation(rotation.z); GLKMatrix4 scaleMatrix = GLKMatrix4MakeScale(scale.x, scale.y, scale.z); GLKMatrix4 translateMatrix = GLKMatrix4MakeTranslation(position.x, position.y, position.z); GLKMatrix4 modelMatrix = GLKMatrix4Multiply(translateMatrix,GLKMatrix4Multiply(scaleMatrix,GLKMatrix4Multiply(zRotationMatrix, GLKMatrix4Multiply(yRotationMatrix, xRotationMatrix)))); GLKMatrix4 viewMatrix = GLKMatrix4MakeLookAt(0, 0, 1, 0, 0, -5, 0, 1, 0); effect.transform.modelviewMatrix = GLKMatrix4Multiply(viewMatrix, modelMatrix); effect.transform.projectionMatrix = GLKMatrix4MakePerspective(0.125*M_TAU, 1.0, 2, 0); effect.texture2d0.name = wallTexture.name; [effect prepareToDraw]; glEnable(GL_DEPTH_TEST); glEnable(GL_CULL_FACE); glEnableVertexAttribArray(GLKVertexAttribPosition); glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 0, triangleVertices); glEnableVertexAttribArray(GLKVertexAttribTexCoord0); glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, 0, textureCoordinates); glDrawArrays(GL_TRIANGLES, 0, 18); glDisableVertexAttribArray(GLKVertexAttribPosition); glDisableVertexAttribArray(GLKVertexAttribTexCoord0); }

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  • Finding the most frequent subtrees in a collection of (parse) trees

    - by peter.murray.rust
    I have a collection of trees whose nodes are labelled (but not uniquely). Specifically the trees are from a collection of parsed sentences (see http://en.wikipedia.org/wiki/Treebank). I wish to extract the most common subtrees from the collection - performance is not (yet) an issue. I'd be grateful for algorithms (ideally Java) or pointers to tools which do this for treebanks. Note that order of child nodes is important. EDIT @mjv. We are working in a limited domain (chemistry) which has a stylised language so the varirty of the trees is not huge - probably similar to children's readers. Simple tree for "the cat sat on the mat". <sentence> <nounPhrase> <article/> <noun/> </nounPhrase> <verbPhrase> <verb/> <prepositionPhrase> <preposition/> <nounPhrase> <article/> <noun/> </nounPhrase> </prepositionPhrase> </verbPhrase> </sentence> Here the sentence contains two identical part-of-speech subtrees (the actual tokens "cat". "mat" are not important in matching). So the algorithm would need to detect this. Note that not all nounPhrases are identical - "the big black cat" could be: <nounPhrase> <article/> <adjective/> <adjective/> <noun/> </nounPhrase> The length of sentences will be longer - between 15 to 30 nodes. I would expect to get useful results from 1000 trees. If this does not take more than a day or so that's acceptable. Obviously the shorter the tree the more frequent, so nounPhrase will be very common. EDIT If this is to be solved by flattening the tree then I think it would be related to Longest Common Substring, not Longest Common Sequence. But note that I don't necessarily just want the longest - I want a list of all those long enough to be "interesting" (criterion yet to be decided).

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  • Mercurial local repository backup

    - by Ricket
    I'm a big fan of backing things up. I keep my important school essays and such in a folder of my Dropbox. I make sure that all of my photos are duplicated to an external drive. I have a home server where I keep important files mirrored across two drives inside the server (like a software RAID 1). So for my code, I have always used Subversion to back it up. I keep the trunk folder with a stable copy of my application, but then I create a branch named with my username, and inside there is my working copy. I make very few changes between commits to that branch, with the understanding that the code in there is my backup. Now I'm looking into Mercurial, and I must admit I haven't truly used it yet so I may have this all wrong. But it seems to me that you have a server-side repository, and then you clone it to a working directory in the form of a local repository. Then as you work on something, you make commits to that local repository, and when things are in a state to be shared with others, you hg push to the parent repository on the server. Between pushes of stable, tested, bug-free code, where is the backup? After doing some thinking, I've come to the conclusion that it is not meant for backup purposes and it assumes you've handled that on your own. I guess I need to keep my Mercurial local repositories in my dropbox or some other backed-up location, since my in-progress code is not pushed to the server. Is this pretty much it, or have I missed something? If you use Mercurial, how do you backup your local repositories? If you had turned on your computer this morning and your hard drive went up in flames (or, more likely, the read head went bad, or the OS corrupted itself, ...), what would be lost? If you spent the past week developing a module, writing test cases for it, documenting and commenting it, and then a virus wipes your local repository away, isn't that the only copy? So then on the flip side, do you create a remote repository for every local repository and push to it all the time? How do you find a balance? How do you ensure your code is backed up? Where is the line between using Mercurial as backup, and using a local filesystem backup utility to keep your local repositories safe?

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  • Memory issues - Living vs. overall -> app is killed

    - by D33
    I'm trying to check my applications memory issues in Instruments. When I load the application I play some sounds and show some animations in UIImageViews. To save some memory I load the sounds only when I need it and when I stop playing it I free it from the memory. problem 1: My application is using about 5.5MB of Living memory. BUT The Overall section is growing after start to 20MB and then it's slowly growing (about 100kB/sec). But responsible Library is OpenAL (OAL::Buffer), dyld (_dyld_start)-I am not sure what this really is, and some other stuff like ft_mem_qrealloc, CGFontStrikeSetValue, … problem 2: When the overall section breaks about 30MB, application crashes (is killed). According to the facts I already read about overall memory, it means then my all allocations and deallocation is about 30MB. But I don't really see the problem. When I need some sound for example I load it to the memory and when I don't need it anymore I release it. But that means when I load 1MB sound, this operation increase overall memory usage with 2MB. Am I right? And when I load 10 sounds my app crashes just because the fact my overall is too high even living is still low??? I am very confused about it. Could someone please help me clear it up? (I am on iOS 5 and using ARC) SOME CODE: creating the sound OpenAL: MYOpenALSound *sound = [[MyOpenALSound alloc] initWithSoundFile:filename willRepeat:NO]; if(!sound) return; [soundDictionary addObject:sound]; playing: [sound play]; dispatch_after(dispatch_time(DISPATCH_TIME_NOW, ((sound.duration * sound.pitch) + 0.1) * NSEC_PER_SEC), dispatch_get_current_queue(), ^{ [soundDictionary removeObjectForKey:[NSNumber numberWithInt:soundID]]; }); } creating the sound with AVAudioPlayer: [musics replaceObjectAtIndex:ID_MUSIC_MAP withObject:[[Music alloc] initWithFilename:@"mapMusic.mp3" andWillRepeat:YES]]; pom = [musics objectAtIndex:musicID]; [pom playMusic]; and stop and free it: [musics replaceObjectAtIndex:ID_MUSIC_MAP withObject:[NSNull null]]; AND IMAGE ANIMATIONS: I load images from big PNG file (this is realated also to my other topic : Memory warning - UIImageView and its animations) I have few UIImageViews and by time I'm setting animation arrays to play Animations... UIImage *source = [[UIImage alloc] initWithCGImage:[[UIImage imageNamed:@"imageSource.png"] CGImage]]; cutRect = CGRectMake(0*dimForImg.width,1*dimForImg.height,dimForImg.width,dimForImg.height); image1 = [[UIImage alloc] initWithCGImage:CGImageCreateWithImageInRect([source CGImage], cutRect)]; cutRect = CGRectMake(1*dimForImg.width,1*dimForImg.height,dimForImg.width,dimForImg.height); ... image12 = [[UIImage alloc] initWithCGImage:CGImageCreateWithImageInRect([source CGImage], cutRect)]; NSArray *images = [[NSArray alloc] initWithObjects:image1, image2, image3, image4, image5, image6, image7, image8, image9, image10, image11, image12, image12, image12, nil]; and this array I just use simply like : myUIImageView.animationImages = images, ... duration -> startAnimating

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  • Making Global Struct in C++ Program

    - by mosg
    Hello world! I am trying to make global structure, which will be seen from any part of the source code. I need it for my big Qt project, where some global variables needed. Here it is: 3 files (global.h, dialog.h & main.cpp). For compilation I use Visual Studio (Visual C++). global.h #ifndef GLOBAL_H_ #define GLOBAL_H_ typedef struct TNumber { int g_nNumber; } TNum; TNum Num; #endif dialog.h #ifndef DIALOG_H_ #define DIALOG_H_ #include <iostream> #include "global.h" using namespace std; class ClassB { public: ClassB() {}; void showNumber() { Num.g_nNumber = 82; cout << "[ClassB][Change Number]: " << Num.g_nNumber << endl; } }; #endif and main.cpp #include <iostream> #include "global.h" #include "dialog.h" using namespace std; class ClassA { public: ClassA() { cout << "Hello from class A!\n"; }; void showNumber() { cout << "[ClassA]: " << Num.g_nNumber << endl; } }; int main(int argc, char **argv) { ClassA ca; ClassB cb; ca.showNumber(); cb.showNumber(); ca.showNumber(); cout << "Exit.\n"; return 0; } When I`m trying to build this little application, compilation works fine, but the linker gives me back an error: 1>dialog.obj : error LNK2005: "struct TNumber Num" (?Num@@3UTNumber@@A) already defined in main.obj Is there exists any solution? Thanks.

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  • Problem with OOP Class Definitions

    - by oben
    Hi, this is Oben from Turkey. I work for my homework in C++ and i have some problems with multiply definitions. My graph class ; class Graph{ private: string name; //Graph name fstream* graphFile; //Graph's file protected: string opBuf; //Operations buffer int containsNode(string); //Query if a node is present Node* nodes; //Nodes in the graph int nofNodes; //Number of nodes in the graph public: static int nOfGraphs; //Number of graphs produced Graph(); //Constructors and destructor Graph(int); Graph(string); Graph(const Graph &); ~Graph(); string getGraphName(); //Get graph name bool addNode(string); //add a node to the graph bool deleteNode(string); //delete a node from the graph bool addEdge(string,string); //add an edge to the graph bool deleteEdge(string,string); //delete an edge from the graph void intersect(const Graph&); //intersect the graph with the <par> void unite(const Graph&); //intersect the graph with the <par> string toString(); //get string representation of the graph void acceptTraverse(BreadthFirst*); void acceptTraverse(DepthFirst *); }; and my traversal class; class Traversal { public: string *visitedNodes; virtual string traverse (const Graph & ); }; class BreadthFirst : public Traversal { public : BreadthFirst(); string traverse(); }; class DepthFirst : public Traversal { public : DepthFirst(); string traverse(); }; My problem is in traversal class , i need to declare Graph class at the same time , in graph class i need traversal class to declare. I have big problems with declerations :) Could you please help me ?

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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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  • Efficient algorithm to distribute work?

    - by Zwei Steinen
    It's a bit complicated to explain but here we go. We have problems like this (code is pseudo-code, and is only for illustrating the problem. Sorry it's in java. If you don't understand, I'd be glad to explain.). class Problem { final Set<Integer> allSectionIds = { 1,2,4,6,7,8,10 }; final Data data = //Some data } And a subproblem is: class SubProblem { final Set<Integer> targetedSectionIds; final Data data; SubProblem(Set<Integer> targetedSectionsIds, Data data){ this.targetedSectionIds = targetedSectionIds; this.data = data; } } Work will look like this, then. class Work implements Runnable { final Set<Section> subSections; final Data data; final Result result; Work(Set<Section> subSections, Data data) { this.sections = SubSections; this.data = data; } @Override public void run(){ for(Section section : subSections){ result.addUp(compute(data, section)); } } } Now we have instances of 'Worker', that have their own state sections I have. class Worker implements ExecutorService { final Map<Integer,Section> sectionsIHave; { sectionsIHave = {1:section1, 5:section5, 8:section8 }; } final ExecutorService executor = //some executor. @Override public void execute(SubProblem problem){ Set<Section> sectionsNeeded = fetchSections(problem.targetedSectionIds); super.execute(new Work(sectionsNeeded, problem.data); } } phew. So, we have a lot of Problems and Workers are constantly asking for more SubProblems. My task is to break up Problems into SubProblem and give it to them. The difficulty is however, that I have to later collect all the results for the SubProblems and merge (reduce) them into a Result for the whole Problem. This is however, costly, so I want to give the workers "chunks" that are as big as possible (has as many targetedSections as possible). It doesn't have to be perfect (mathematically as efficient as possible or something). I mean, I guess that it is impossible to have a perfect solution, because you can't predict how long each computation will take, etc.. But is there a good heuristic solution for this? Or maybe some resources I can read up before I go into designing? Any advice is highly appreciated!

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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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