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  • Saving JQuery Draggable Sitemap Values Correctly

    - by mdolon
    I am trying to implement Boagworld's Sitemap tutorial, however I am running into difficulty trying to correctly save the child/parent relationships. The HTML is as follows, however populated with other items as well: <input type="hidden" name="sitemap-order" id="sitemap-order" value="" /> <ul id=”sitemap”> <li id="1"> <dl> <dt><a href=”#”>expand/collapse</a> <a href=”#”>Page Title</a></dt> <dd>Text Page</dd> <dd>Published</dd> <dd><a href=”#”>delete</a></dd> </dl> <ul><!–child pages–></ul> </li> </ul> And here is the JQuery code: $('#sitemap li').prepend('<div class="dropzone"></div>'); $('#sitemap li').draggable({ handle: ' > dl', opacity: .8, addClasses: false, helper: 'clone', zIndex: 100 }); var order = ""; $('#sitemap dl, #sitemap .dropzone').droppable({ accept: '#sitemap li', tolerance: 'pointer', drop: function(e, ui) { var li = $(this).parent(); var child = !$(this).hasClass('dropzone'); //If this is our first child, we'll need a ul to drop into. if (child && li.children('ul').length == 0) { li.append('<ul/>'); } //ui.draggable is our reference to the item that's been dragged. if (child) { li.children('ul').append(ui.draggable); }else { li.before(ui.draggable); } //reset our background colours. li.find('dl,.dropzone').css({ backgroundColor: '', backgroundColor: '' }); li.find('.dropzone').css({ height: '8px', margin: '0' }); // THE PROBLEM: var parentid = $(this).parent().attr('id'); menuorder += ui.draggable.attr('id')+'=>'+parentid+','; $("#sitemap-order").val(order); }, over: function() { $(this).filter('dl').css({ backgroundColor: '#ccc' }); $(this).filter('.dropzone').css({ backgroundColor: '#aaa', height: '30px', margin: '5px 0'}); }, out: function() { $(this).filter('dl').css({ backgroundColor: '' }); $(this).filter('.dropzone').css({ backgroundColor: '', height: '8px', margin: '0' }); } }); When moving items into the top-level (without parents), the parentid value I get is of the first list item (the parent container), so I can never remove the parent value and have a top-level item. Is there a no-brainer answer that I'm just not seeing right now? Any help is appreciated.

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  • How to pass operators as parameters

    - by Rodion Ingles
    I have to load an array of doubles from a file, multiply each element by a value in a table (different values for different elements), do some work on it, invert the multiplication (that is, divide) and then save the data back to file. Currently I implement the multiplication and division process in two separate methods. Now there is some extra work behind the scenes but apart from the specific statements where the multiplication/division occurs, the rest of the code is identical. As you can imagine, with this approach you have to be very careful making any changes. The surrounding code is not trivial, so its either a case of manually editing each method or copying changes from one method to the other and remembering to change the * and / operators. After too many close calls I am fed up of this and would like to make a common function which implements the common logic and two wrapper functions which pass which operator to use as a parameter. My initial approach was to use function pointers: MultiplyData(double data) { TransformData(data, &(operator *)); } DivideData(double data) { TransformData(data, &(operator /)); } TransformData(double data, double (*func)(double op1, double op2)) { /* Do stuff here... */ } However, I can't pass the operators as pointers (is this because it is an operator on a native type?), so I tried to use function objects. Initially I thought that multiplies and divides functors in <functional> would be ideal: MultiplyData(double data) { std::multiplies<double> multFunct; TransformData(data, &multFunct); } DivideData(double data) { std::divides<double> divFunct; TransformData(data, &divFunct); } TransformData(double data, std::binary_function<double, double, double> *funct) { /* Do stuff here... */ } As you can see I was trying to use a base class pointer to pass the functor polymorphically. The problem is that std::binary_function does not declare an operator() member for the child classes to implement. Is there something I am missing, or is the solution to implement my own functor heirarchy (which really seems more trouble than it is worth)?

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  • Are Objective-C initializers allowed to share the same name?

    - by NattKatt
    I'm running into an odd issue in Objective-C when I have two classes using initializers of the same name, but differently-typed arguments. For example, let's say I create classes A and B: A.h: #import <Cocoa/Cocoa.h> @interface A : NSObject { } - (id)initWithNum:(float)theNum; @end A.m: #import "A.h" @implementation A - (id)initWithNum:(float)theNum { self = [super init]; if (self != nil) { NSLog(@"A: %f", theNum); } return self; } @end B.h: #import <Cocoa/Cocoa.h> @interface B : NSObject { } - (id)initWithNum:(int)theNum; @end B.m: #import "B.h" @implementation B - (id)initWithNum:(int)theNum { self = [super init]; if (self != nil) { NSLog(@"B: %d", theNum); } return self; } @end main.m: #import <Foundation/Foundation.h> #import "A.h" #import "B.h" int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; A *a = [[A alloc] initWithNum:20.0f]; B *b = [[B alloc] initWithNum:10]; [a release]; [b release]; [pool drain]; return 0; } When I run this, I get the following output: 2010-04-26 20:44:06.820 FnTest[14617:a0f] A: 20.000000 2010-04-26 20:44:06.823 FnTest[14617:a0f] B: 1 If I reverse the order of the imports so it imports B.h first, I get: 2010-04-26 20:45:03.034 FnTest[14635:a0f] A: 0.000000 2010-04-26 20:45:03.038 FnTest[14635:a0f] B: 10 For some reason, it seems like it's using the data type defined in whichever @interface gets included first for both classes. I did some stepping through the debugger and found that the isa pointer for both a and b objects ends up the same. I also found out that if I no longer make the alloc and init calls inline, both initializations seem to work properly, e.g.: A *a = [A alloc]; [a initWithNum:20.0f]; If I use this convention when I create both a and b, I get the right output and the isa pointers seem to be different for each object. Am I doing something wrong? I would have thought multiple classes could have the same initializer names, but perhaps that is not the case.

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  • unable to trigger event in IE during clonning

    - by Abhimanyu
    Following is the code which will clone a set of div with their events(onclick) which is working fine for FF but in case of IE it is not firing events associated with each div. <html> <head> <style type='text/css'> .firstdiv{ border:1px solid red; } </style> <script language="JavaScript"> function show_tooltip(idx,condition,ev) { alert(idx +"=="+condition+"=="+ev); } function createCloneNode () { var cloneObj = document.getElementById("firstdiv").cloneNode(true); document.getElementById("maindiv").appendChild(cloneObj); } function init(){ var mainDiv = document.createElement("div"); mainDiv.id = 'maindiv'; var firstDiv = document.createElement("div"); firstDiv.id ='firstdiv'; firstDiv.className ='firstdiv'; for(var j=0;j<4;j++) { var summaryDiv = document.createElement("div"); summaryDiv.id = "sDiv"+j summaryDiv.className ='summaryDiv'; summaryDiv.onmouseover = function() {this.setAttribute("style","text-decoration:underline;cursor:pointer;");} summaryDiv.onmouseout = function() {this.setAttribute("style","text-decoration:none;");} summaryDiv.setAttribute("onclick", "show_tooltip("+j+",'view_month',event)"); summaryDiv.innerHTML = 'Div'+j; firstDiv.appendChild(summaryDiv); } mainDiv.appendChild(firstDiv); var secondDiv = document.createElement("div"); var linkDiv = document.createElement("div"); linkDiv.innerHTML ='create clone of above element'; linkDiv.onclick = function() { createCloneNode(); } secondDiv.appendChild(linkDiv); mainDiv.appendChild(secondDiv); document.body.appendChild(mainDiv); } </script> </head> <body> <script language="JavaScript"> init() </script> </body> </html> can anybody tell me whats the problem in above code please correct me..

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  • template pass by const reference

    - by 7vies
    Hi, I've looked over a few similar questions, but I'm still confused. I'm trying to figure out how to explicitly (not by compiler optimization etc) and C++03-compatible avoid copying of an object when passing it to a template function. Here is my test code: #include <iostream> using namespace std; struct C { C() { cout << "C()" << endl; } C(const C&) { cout << "C(C)" << endl; } ~C() { cout << "~C()" << endl; } }; template<class T> void f(T) { cout << "f<T>" << endl; } template<> void f(C c) { cout << "f<C>" << endl; } // (1) template<> void f(const C& c) { cout << "f<C&>" << endl; } // (2) int main() { C c; f(c); return 0; } (1) accepts the object of type C, and makes a copy. Here is the output: C() C(C) f<C> ~C() ~C() So I've tried to specialize with a const C& parameter (2) to avoid this, but this simply doesn't work (apparently the reason is explained in this question). Well, I could "pass by pointer", but that's kind of ugly. So is there some trick that would allow to do that somehow nicely? EDIT: Oh, probably I wasn't clear. I already have a templated function template<class T> void f(T) {...} But now I want to specialize this function to accept a const& to another object: template<> void f(const SpecificObject&) {...} But it only gets called if I define it as template<> void f(SpecificObject) {...}

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  • Casting to derived type problem in C++

    - by GONeale
    Hey there everyone, I am quite new to C++, but have worked with C# for years, however it is not helping me here! :) My problem: I have an Actor class which Ball and Peg both derive from on an objective-c iphone game I am working on. As I am testing for collision, I wish to set an instance of Ball and Peg appropriately depending on the actual runtime type of actorA or actorB. My code that tests this as follows: // Actors that collided Actor *actorA = (Actor*) bodyA->GetUserData(); Actor *actorB = (Actor*) bodyB->GetUserData(); Ball* ball; Peg* peg; if (static_cast<Ball*> (actorA)) { // true ball = static_cast<Ball*> (actorA); } else if (static_cast<Ball*> (actorB)) { ball = static_cast<Ball*> (actorB); } if (static_cast<Peg*> (actorA)) { // also true?! peg = static_cast<Peg*> (actorA); } else if (static_cast<Peg*> (actorB)) { peg = static_cast<Peg*> (actorB); } if (peg != NULL) { [peg hitByBall]; } Once ball and peg are set, I then proceed to run the hitByBall method (objective c). Where my problem really lies is in the casting procedurel Ball casts fine from actorA; the first if (static_cast<>) statement steps in and sets the ball pointer appropriately. The second step is to assign the appropriate type to peg. I know peg should be a Peg type and I previously know it will be actorB, however at runtime, detecting the types, I was surprised to find actually the third if (static_cast<>) statement stepped in and set this, this if statement was to check if actorA was a Peg, which we already know actorA is a Ball! Why would it have stepped here and not in the fourth if statement? The only thing I can assume is how casting works differently from c# and that is it finds that actorA which is actually of type Ball derives from Actor and then it found when static_cast<Peg*> (actorA) is performed it found Peg derives from Actor too, so this is a valid test? This could all come down to how I have misunderstood the use of static_cast. How can I achieve what I need? :) I'm really uneasy about what feels to me like a long winded brute-casting attempt here with a ton of ridiculous if statements. I'm sure there is a more elegant way to achieve a simple cast to Peg and cast to Ball dependent on actual type held in actorA and actorB. Hope someone out there can help! :) Thanks a lot.

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  • C++ class member functions instantiated by traits

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched Stack Overflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate non-virtual member functions? The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state information was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (VC++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice?

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  • Refactoring Singleton Overuse

    - by drharris
    Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

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  • Linked lists in Java - help with assignment

    - by user368241
    Representation of a string in linked lists In every intersection in the list there will be 3 fields : The letter itself. The number of times it appears consecutively. A pointer to the next intersection in the list. The following class CharNode represents a intersection in the list : public class CharNode { private char _data; private int _value; private charNode _next; public CharNode (char c, int val, charNode n) { _data = c; _value = val; _next = n; } public charNode getNext() { return _next; } public void setNext (charNode node) { _next = node; } public int getValue() { return _value; } public void setValue (int v) { value = v; } public char getData() { return _data; } public void setData (char c) { _data = c; } } The class StringList represents the whole list : public class StringList { private charNode _head; public StringList() { _head = null; } public StringList (CharNode node) { _head = node; } } Add methods to the class StringList according to the details : (I will add methods gradually according to my specific questions) (Pay attention, these are methods from the class String and we want to fulfill them by the representation of a string by a list as explained above) public int indexOf (int ch) - returns the index in the string it is operated on of the first appeareance of the char "ch". If the char "ch" doesn't appear in the string, returns -1. If the value of fromIndex isn't in the range, returns -1. Pay attention to all the possible error cases. Write what is the time complexity and space complexity of every method that you wrote. Make sure the methods you wrote are effective. It is NOT allowed to use ready classes of Java. It is NOT allowed to move to string and use string operations. Here is my try to write the method indexOf (int ch). Kindly assist me with fixing the bugs so I can move on. public int indexOf (int ch) { int count = 0; charNode pose = _head; if (pose == null ) { return -1; } for (pose = _head; pose!=null && pose.getNext()!='ch'; pose = pose.getNext()) { count++; } if (pose!=null) return count; else return -1; }

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  • I'm having trouble traversing a newly appended DOM element with jQuery

    - by culov
    I have a form that I want to be used to add entries. Once an entry is added, the original form should be reset to prepare it for the next entry, and the saved form should be duplicated prior to resetting and appended onto a div for 'storedEntries.' This much is working (for the most part), but Im having trouble accessing the newly created form... I need to change the value attribute of the submit button from 'add' to 'edit' so properly communicate what clicking that button should do. heres my form: <div class="newTruck"> <form id="addNewTruck" class='updateschedule' action="javascript:sub(sTime.value, eTime.value, lat.value, lng.value, street.value);"> <b style="color:green;">Opening at: </b> <input id="sTime" name="sTime" title="Opening time" value="Click to set opening time" class="datetimepicker"/> <b style="color:red;">Closing at: </b> <input id="eTime" name= "eTime" title="Closing time" value="Click to set closing time" class="datetimepicker"/> <label for='street'>Address</label> <input type='text' name='street' id='street' class='text' autocomplete='off'/> <input id='submit' class='submit' style="cursor: pointer; cursor: hand;" type="submit" value='Add new stop'/> <div id='suggests' class='auto_complete' style='display:none'></div> <input type='hidden' name='lat' id='lat'/> <input type='hidden' name='lng' id='lng'/> ive tried using a hundred different selectors with jquery to no avail... heres my script as it stands: function cloneAndClear(){ var id = name+now; $j("#addNewTruck").clone(true).attr("id",id).appendTo(".scheduledTrucks"); $j('#'+id).filter('#submit').attr('value', 'Edit'); $j("#addNewTruck")[0].reset(); createPickers(); } the element is properly cloned and inserted into the div, but i cant find a way to access this element... the third line in the script never works. Another problem i am having is that the 'values' in the cloned form revert back to the value in the source of the html rather than what the user inputs. advice on how to solve either of these issues is greatly appreciated!

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  • What is GC holes?

    - by tianyi
    I wrote a long TCP connection socket server in C#. Spike in memory in my server happens. I used dotNet Memory Profiler(a tool) to detect where the memory leaks. Memory Profiler indicates the private heap is huge, and the memory is something like below(the number is not real,what I want to show is the GC0 and GC2's Holes are very very huge, the data size is normal): Managed heaps - 1,500,000KB Normal heap - 1400,000KB Generation #0 - 600,000KB Data - 100,000KB "Holes" - 500,000KB Generation #1 - xxKB Data - 0KB "Holes" - xKB Generation #2 - xxxxxxxxxxxxxKB Data - 100,000KB "Holes" - 700,000KB Large heap - 131072KB Large heap - 83KB Overhead/unused - 130989KB Overhead - 0KB Howerver, what is GC hole? I read an article about the hole: http://kaushalp.blogspot.com/2007/04/what-is-gc-hole-and-how-to-create-gc.html The author said : The code snippet below is the simplest way to introduce a GC hole into the system. //OBJECTREF is a typedef for Object*. { PointerTable *pTBL = o_pObjectClass->GetPointerTable(); OBJECTREF aObj = AllocateObjectMemory(pTBL); OBJECTREF bObj = AllocateObjectMemory(pTBL); //WRONG!!! “aObj” may point to garbage if the second //“AllocateObjectMemory” triggered a GC. DoSomething (aOb, bObj); } All it does is allocate two managed objects, and then does something with them both. This code compiles fine, and if you run simple pre-checkin tests, it will probably “work.” But this code will crash eventually. Why? If the second call to “AllocateObjectMemory” triggers a GC, that GC discards the object instance you just assigned to “aObj”. This code, like all C++ code inside the CLR, is compiled by a non-managed compiler and the GC cannot know that “aObj” holds a root reference to an object you want kept live. ======================================================================== I can't understand what he explained. Does the sample mean aObj becomes a wild pointer after GC? Is it mean { aObj = (*aObj)malloc(sizeof(object)); free(aObj); function(aObj);? } ? I hope somebody can explain it.

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  • close file with fclose() but file still in use

    - by Marco
    Hi all, I've got a problem with deleting/overwriting a file using my program which is also being used(read) by my program. The problem seems to be that because of the fact my program is reading data from the file (output.txt) it puts the file in a 'in use' state which makes it impossible to delete or overwrite the file. I don't understand why the file stays 'in use' because I close the file after use with fclose(); this is my code: bool bBool = true while(bBool){ //Run myprogram.exe tot generate (a new) output.txt //Create file pointer and open file FILE* pInputFile = NULL; pInputFile = fopen("output.txt", "r"); // //then I do some reading using fscanf() // //And when I'm done reading I close the file using fclose() fclose(pInputFile); //The next step is deleting the output.txt if( remove( "output.txt" ) == -1 ){ //ERROR }else{ //Succesfull } } I use fclose() to close the file but the file remains in use by my program until my program is totally shut down. What is the solution to free the file so it can be deleted/overwrited? In reality my code isn't a loop without an end ; ) Thanks in advance! Marco Update Like ask a part of my code which also generates the file 'in use'. This is not a loop and this function is being called from the main(); Here is a piece of code: int iShapeNr = 0; void firstRun() { //Run program that generates output.txt runProgram(); //Open Shape data file FILE* pInputFile = NULL; int iNumber = 0; pInputFile = fopen("output.txt", "r"); //Put all orientations of al detected shapes in an array int iShapeNr = 0; int iRotationBuffer[1024];//1024 is maximum detectable shapes, can be changed in RoboRealm int iXMinBuffer[1024]; int iXMaxBuffer[1024]; int iYMinBuffer[1024]; int iYMaxBuffer[1024]; while(feof(pInputFile) == 0){ for(int i=0;i<9;i++){ fscanf(pInputFile, "%d", &iNumber); fscanf(pInputFile, ","); if(i == 1) { iRotationBuffer[iShapeNr] = iNumber; } if(i == 3){//xmin iXMinBuffer[iShapeNr] = iNumber; } if(i == 4){//xmax iXMaxBuffer[iShapeNr] = iNumber; } if(i == 5){//ymin iYMinBuffer[iShapeNr] = iNumber; } if(i == 6){//ymax iYMaxBuffer[iShapeNr] = iNumber; } } iShapeNr++; } fflush(pInputFile); fclose(pInputFile); } The while loop parses the file. The output.txt contains sets of 9 variables, the number of sets is unknown but always in sets of 9. output.txt could contain for example: 0,1,2,3,4,5,6,7,8,8,7,6,5,4,1,2,3,0

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  • jQuery .live() not working.

    - by Silvio Iannone
    Hi there, my actual problem is that .live() jQuery method is not working. This si the code where i use it: jQuery.fn.sb_animateMenuItem = function() { var mousehoverColor = '#0089F7'; var duration = 250; return this.each(function() { var originalColor = $(this).css('background-color'); $(this).live('mouseover', function() { this.style.cursor = 'pointer'; $(this).animate().stop(); $(this).animate( { backgroundColor: mousehoverColor }, duration); }); $(this).live('mouseout', function() { this.style.cursor = 'default'; $(this).animate( { backgroundColor: originalColor }, duration); }); }); }; This snipped is used i another page in this way: <script type="text/javascript" src="ui/js/jquery-1.4.2.js"></script> <script type="text/javascript" src="ui/js/jquery-ui-1.8.1.custom.min.js"></script> <script type="text/javascript" src="ui/js/color.js"></script> <script type="text/javascript" src="engine/js/tiny_mce/tiny_mce.js"></script> <script type="text/javascript" src="ui/js/ui.js"></script> <script type="text/javascript"> // UI effects $(document).ready(function() { $('button').sb_animateButton(); $('input').sb_animateInput(); $('.top_menu_item').sb_animateMenuItem(); $('.top_menu_item_right').sb_animateMenuItem(); $('.left_menu_item').sb_animateMenuItem(); }); </script> Since my site uses AJAX requests i used the .live method in the first snippet, but when i load the page the effects are not applied the the button/input... tags. If i remove the .live method and use the 'normal' way, ui effects defined in the first snipped are applied but only the the elements loaded before any AJAX request. The elements loaded after the ajax request are not affected by first snippet (though they have the same selector). Thanks for helping.

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  • C++ linked list based tree structure. Sanely move nodes between lists.

    - by krunk
    The requirements: Each Node in the list must contain a reference to its previous sibling Each Node in the list must contain a reference to its next sibling Each Node may have a list of child nodes Each child Node must have a reference to its parent node Basically what we have is a tree structure of arbitrary depth and length. Something like: -root(NULL) --Node1 ----ChildNode1 ------ChildOfChild --------AnotherChild ----ChildNode2 --Node2 ----ChildNode1 ------ChildOfChild ----ChildNode2 ------ChildOfChild --Node3 ----ChildNode1 ----ChildNode2 Given any individual node, you need to be able to either traverse its siblings. the children, or up the tree to the root node. A Node ends up looking something like this: class Node { Node* previoius; Node* next; Node* child; Node* parent; } I have a container class that stores these and provides STL iterators. It performs your typical linked list accessors. So insertAfter looks like: void insertAfter(Node* after, Node* newNode) { Node* next = after->next; after->next = newNode; newNode->previous = after; next->previous = newNode; newNode->next = next; newNode->parent = after->parent; } That's the setup, now for the question. How would one move a node (and its children etc) to another list without leaving the previous list dangling? For example, if Node* myNode exists in ListOne and I want to append it to listTwo. Using pointers, listOne is left with a hole in its list since the next and previous pointers are changed. One solution is pass by value of the appended Node. So our insertAfter method would become: void insertAfter(Node* after, Node newNode); This seems like an awkward syntax. Another option is doing the copying internally, so you'd have: void insertAfter(Node* after, const Node* newNode) { Node *new_node = new Node(*newNode); Node* next = after->next; after->next = new_node; new_node->previous = after; next->previous = new_node; new_node->next = next; new_node->parent = after->parent; } Finally, you might create a moveNode method for moving and prevent raw insertion or appending of a node that already has been assigned siblings and parents. // default pointer value is 0 in constructor and a operator bool(..) // is defined for the Node bool isInList(const Node* node) const { return (node->previous || node->next || node->parent); } // then in insertAfter and friends if(isInList(newNode) // throw some error and bail I thought I'd toss this out there and see what folks came up with.

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  • random quote generator with php, ajax and mysql

    - by fusion
    i've tried using this code and this to make a random quote generator, but it doesn't display anything. my questions are: what is wrong with my code? in the above tut, the quote is generated on a button click, i'd like a random quote to be displayed every 30 mins automatically. how do i do this? //////////////////////// quote.html: <!DOCTYPE html> <script src="ajax.js" type="text/javascript"></script> <body> <!–create the div for the quotes land–> <div id="quote"><strong>this</strong></div> <div><a style="cursor:pointer" onclick="run_query();">Next quote …</a></div> </body> </html> ///////////////////// quote.php: <?php include 'config.php'; // 'text' is the name of your table that contains // the information you want to pull from $rowcount = mysql_query("select count(*) as rows from quotes"); // Gets the total number of items pulled from database. while ($row = mysql_fetch_assoc($rowcount)) { $max = $row["rows"]; } // Selects an item's index at random $rand = rand(1,$max)-1; $result = mysql_query("select * from quotes limit $rand, 1"); $row = mysql_fetch_array($result); $randomOutput = $row['storedText']; echo '<p>' . $randomOutput . '</p>'; //////////// ajax.js: var xmlHttp function run_query() { xmlHttp=GetXmlHttpObject(); if (xmlHttp==null) { alert ("This browser does not support HTTP Request"); return; } // end if var url="quote.php"; xmlHttp.onreadystatechange=stateChanged; xmlHttp.open("GET",url,true); xmlHttp.send(null); } //end function function stateChanged(){ if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){ document.getElementById("quote").innerHTML=xmlHttp.responseText; } //end if } //end function function GetXmlHttpObject() { var xmlHttp=null; try { // For these browsers: Firefox, Opera 8.0+, Safari xmlHttp=new XMLHttpRequest(); }catch (e){ //For Internet Explorer try{ xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); } } return xmlHttp; } //end function

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  • Make sense of Notification Watcher source objective-c

    - by Chris
    From Notification Watcher source. - (void)selectNotification:(NSNotification*)aNotification { id sender = [aNotification object]; [selectedDistNotification release]; selectedDistNotification = nil; [selectedWSNotification release]; selectedWSNotification = nil; NSNotification **targetVar; NSArray **targetList; if (sender == distNotificationList) { targetVar = &selectedDistNotification; targetList = &distNotifications; } else { targetVar = &selectedWSNotification; targetList = &wsNotifications; } if ([sender selectedRow] != -1) { [*targetVar autorelease]; *targetVar = [[*targetList objectAtIndex:[sender selectedRow]] retain]; } if (*targetVar == nil) { [objectText setStringValue:@""]; } else { id obj = [*targetVar object]; NSMutableAttributedString *objStr = nil; if (obj == nil) { NSFont *aFont = [objectText font]; NSDictionary *attrDict = italicAttributesForFont(aFont); objStr = [[NSMutableAttributedString alloc] initWithString:@"(null)" attributes:attrDict]; } else { /* Line 1 */ objStr = [[NSMutableAttributedString alloc] initWithString: [NSString stringWithFormat:@" (%@)", [obj className]]]; [objStr addAttributes:italicAttributesForFont([objectText font]) range:NSMakeRange(1,[[obj className] length]+2)]; if ([obj isKindOfClass:[NSString class]]) { [objStr replaceCharactersInRange:NSMakeRange(0,0) withString:obj]; } else if ([obj respondsToSelector:@selector(stringValue)]) { [objStr replaceCharactersInRange:NSMakeRange(0,0) withString:[obj performSelector:@selector(stringValue)]]; } else { // Remove the space since we have no value to display [objStr replaceCharactersInRange:NSMakeRange(0,1) withString:@""]; } } [objectText setObjectValue:objStr]; /* LINE 2 */ [objStr release]; } [userInfoList reloadData]; } Over at //LINE 2 objStr is being released. Is this because we are assigning it with alloc in //LINE 1? Also, why is //LINE 1 not: objStr = [NSMutableAttributedString* initWithString:@"(null)" attributes:attrDict] If I create a new string like (NSString*) str = [NSString initWithString:@"test"]; ... str = @"another string"; Would I have to release str, or is this wrong and if I do that I have to use [[NSString alloc] initWithString:@"test"]? Why isn't the pointer symbol used as in [[NSString* alloc] ...? Thanks

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  • Where are the function literals c++?

    - by academicRobot
    First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one.

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  • How does System.TraceListener prepend message with process name?

    - by btlog
    I have been looking at using System.Diagnostics.Trace for doing logging is a very basic app. Generally it does all I need it to do. The downside is that if I call Trace.TraceInformation("Some info"); The output is "SomeApp.Exe Information: 0: Some info". Initally this entertained me but no longer. I would like to just output "Some info" to console. So I thought writing a cusom TraceListener, rather than using the inbuilt ConsoleTraceListener, would solve the problem. I can see a specific format that I want all the text after the second colon. Here is my attempt to see if this would work. class LogTraceListener : TraceListener { public override void Write(string message) { int firstColon = message.IndexOf(":"); int secondColon = message.IndexOf(":", firstColon + 1); Console.Write(message); } public override void WriteLine(string message) { int firstColon = message.IndexOf(":"); int secondColon = message.IndexOf(":", firstColon + 1); Console.WriteLine(message); } } If I output the value of firstColon it is always -1. If I put a break point the message is always just "Some info". Where does all the other information come from? So I had a look at the call stack at the point just before Console.WriteLine was called. The method that called my WriteLine method is: System.dll!System.Diagnostics.TraceListener.TraceEvent(System.Diagnostics.TraceEventCache eventCache, string source, System.Diagnostics.TraceEventType eventType, int id, string message) + 0x33 bytes When I use Reflector to look at this message it all seems pretty straight forward. I can't see any code that changes the value of the string after I have sent it to Console.WriteLine. The only method that could posibly change the underlying string value is a call to UnsafeNativeMethods.EventWriteString which has a parameter that is a pointer to the message. Does anyone understand what is going on here and whether I can change the output to be just my message with out the additional fluff. It seems like evil magic that I can pass a string "Some info" to Console.WriteLine (or any other method for that matter) and the string that output is different.

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  • mysql timeout - c/C++

    - by user1262876
    Guys i'm facing a problem with this code, the problem is the timeout by timeout i mean the time it takes the program to tell me if the server is connected or not. If i use my localhost i get the answer fast, but when i connect to outside my localhost it takes 50sc - 1.5 min to response and the program frezz until it done. HOw can i fix the frezzing, or make my own timeout, like if still waiting after 50sc, tell me connection failed and stop? please use codes as help, becouse i would understand it better, thanks for any help i get PS: USING MAC #include "mysql.h" #include <stdio.h> #include <stdlib.h> // Other Linker Flags: -lmysqlclient -lm -lz // just going to input the general details and not the port numbers struct connection_details { char *server; char *user; char *password; char *database; }; MYSQL* mysql_connection_setup(struct connection_details mysql_details) { // first of all create a mysql instance and initialize the variables within MYSQL *connection = mysql_init(NULL); // connect to the database with the details attached. if (!mysql_real_connect(connection,mysql_details.server, mysql_details.user, mysql_details.password, mysql_details.database, 0, NULL, 0)) { printf("Conection error : %s\n", mysql_error(connection)); exit(1); } return connection; } MYSQL_RES* mysql_perform_query(MYSQL *connection, char *sql_query) { // send the query to the database if (mysql_query(connection, sql_query)) { printf("MySQL query error : %s\n", mysql_error(connection)); exit(1); } return mysql_use_result(connection); } int main() { MYSQL *conn; // the connection MYSQL_RES *res; // the results MYSQL_ROW row; // the results row (line by line) struct connection_details mysqlD; mysqlD.server = (char*)"Localhost"; // where the mysql database is mysqlD.user = (char*)"root"; // the root user of mysql mysqlD.password = (char*)"123456"; // the password of the root user in mysql mysqlD.database = (char*)"test"; // the databse to pick // connect to the mysql database conn = mysql_connection_setup(mysqlD); // assign the results return to the MYSQL_RES pointer res = mysql_perform_query(conn, (char*) "SELECT * FROM me"); printf("MySQL Tables in mysql database:\n"); while ((row = mysql_fetch_row(res)) !=NULL) printf("%s - %s\n", row[0], row[1], row[2]); // <-- Rows /* clean up the database result set */ mysql_free_result(res); /* clean up the database link */ mysql_close(conn); return 0; }

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  • hi this is my css horizontal menu i need the submeus for this?

    - by kalaivani
    /* CSS Document */ . rhm1{ width:780px; height:64px; margin:0 auto; background:url(images/rhm1_bg.g if) repeat-x; } .rhm1-left{ background:url(images/rhm1_l.gi f) no-repeat; width:15px; height:64px; float:left; } .rhm1-right{ background:url(images/rhm1_r.gi f) no-repeat; width:15px; height:64px; float:right; } .rhm1-bg{ background:url(images/rhm1_bg.g if) repeat-x; height:64px; } .rhm1-bg ul{ list-style:none; margin:0 auto; } .rhm1-bg li{ float:left; list-style:none; } .rhm1-bg li a{ float:left; display:block; color:#ffe8cc; text-decoration:none; font:12px 'Lucida Sans', sans-serif; font-weight:bold; padding:0 0 0 18px; height:64px; line-height:40px; text-align:center; cursor:pointer; } .rhm1-bg li a span{ float:left; display:block; padding:0 32px 0 18px; } .rhm1-bg li.current a{ color:#fff; background:url(images/rhm1_hove r_l.gif) no-repeat left 5px; } .rhm1-bg li.current a span{ color:#fff; background:url(images/rhm1_hove r_r.gif) no-repeat right 5px; } .rhm1-bg li a:hover{ color:#fff; background:url(images/rhm1_hove r_l.gif) no-repeat left 5px; } .rhm1-bg li a:hover span{ color:#fff; background:url(images/rhm1_hove r_r.gif) no-repeat right 5px; }

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  • Syntax error while copying an multidimensional array to another in C

    - by mantuko
    We are programming a ST269 microcontroller which has two IR distance sensors. To calibrate these sensors we made one table for each sensor with the distance we measured and the corresponding value we get from the ADC. Now we want to use one function to approximate the values in between. So we defined two two-dimensional arrays (one for each sensor) as global variables. In our function we then want to copy the one array we want to work with to a working array and approximate our values. So here's the code: ... unsigned int ir_werte_re[][] = { {8,553}, ... {83,133} }; unsigned int ir_werte_li[][] = { {8,566}, ... {83,147} }; ... unsigned int geradenaproximation(unsigned int messwert, unsigned int seite) { unsigned int working_array[16][16]; unsigned int i = 0; if (seite == 0) { for (i = 0; i < sizeof(working_array); i++) { working_array[i][0] = ir_werte_li[i][0]; i++; } } else { for (i = 0; i < sizeof(working_array); i++) { working_array[i][0] = ir_werte_re[i][0]; i++; } } i = 0; unsigned int y1 = 0; unsigned int x1 = 0; ... } This code is in a file called sensor.c. We didn't write anything about our global arrays in the sensor.h should we? The sensor.h of course is included in our main.c and there the function is called. We also tried to copy the arrays via memcpy(working_array, ir_werte_li, sizeof(working_array)); And in every way we do this we get a syntax error near unsigned in the line where we're declaring unsigned int y1 = 0; and I'm pretty sure that there is no syntax error in this line : ) The last time I spend coding in C is a few years away so I'm not sure if the way we try to do this is good. Perhaps we can solve this by using a pointer instead of really copying the array or something. So please help me out I'll appreciate your bits on this.

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  • Two collections and a for loop. (Urgent help needed) Checking an object variable against an inputted

    - by Elliott
    Hi there, I'm relatively new to java, I'm certain the error is trivial. But can't for the life of me spot it. I have an end of term exam on monday and currently trying to get to grips with past papers! Anyway heregoes, in another method (ALGO_1) I search over elements of and check the value H_NAME equals a value entered in the main. When I attempt to run the code I get a null pointer exception, also upon trying to print (with System.out.println etc) the H_NAME value after each for loop in the snippet I also get a null statement returned to me. I am fairly certain that the collection is simply not storing the data gathered up by the Scanner. But then again when I check the collection size with size() it is about the right size. Either way I'm pretty lost and would appreciate the help. Main questions I guess to ask are: from the readBackground method is the data.add in the wrong place? is the snippet simply structured wrongly? oh and another point when I use System.out.println to check the Background object values name, starttime, increment etc they print out fine. Thanks in advance.(PS im guessing the formatting is terrible, apologies.) snippet of code: for(Hydro hd: hydros){ System.out.println(hd.H_NAME); for(Background back : backgs){ System.out.println(back.H_NAME); if(back.H_NAME.equals(hydroName)){ //get error here public static Collection<Background> readBackground(String url) throws IOException { URL u = new URL(url); InputStream is = u.openStream(); InputStreamReader isr = new InputStreamReader(is); BufferedReader b = new BufferedReader(isr); String line =""; Vector<Background> data = new Vector<Background>(); while((line = b.readLine())!= null){ Scanner s = new Scanner(line); String name = s.next(); double starttime = Double.parseDouble(s.next()); double increment = Double.parseDouble(s.next()); double sum = 0; double p = 0; double nterms = 0; while((s.hasNextDouble())){ p = Double.parseDouble(s.next()); nterms++; sum += p; } double pbmean = sum/nterms; Background SAMP = new Background(name, starttime, increment, pbmean); data.add(SAMP); } return data; } Edit/Delete Message

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  • Is there a potential for resource leak/double free here?

    - by nhed
    The following sample (not compiled so I won't vouch for syntax) pulls two resources from resource pools (not allocated with new), then "binds" them together with MyClass for the duration of a certain transaction. The transaction, implemented here by myFunc, attempts to protect against leakage of these resources by tracking their "ownership". The local resource pointers are cleared when its obvious that instantiation of MyClass was successful. The local catch, as well as the destructor ~MyClass return the resources to their pool (double-frees are protected by teh above mentioned clearing of the local pointers). Instantiation of MyClass can fail and result in an exception at two steps (1) actual memory allocation, or (2) at the constructor body itself. I do not have a problem with #1, but in the case of #2, if the exception is thrown AFTER m_resA & m_resB were set. Causing both the ~MyClass and the cleanup code of myFunc to assume responsibility for returning these resources to their pools. Is this a reasonable concern? Options I have considered, but didn't like: Smart pointers (like boost's shared_ptr). I didn't see how to apply to a resource pool (aside for wrapping in yet another instance). Allowing double-free to occur at this level but protecting at the resource pools. Trying to use the exception type - trying to deduce that if bad_alloc was caught that MyClass did not take ownership. This will require a try-catch in the constructor to make sure that any allocation failures in ABC() ...more code here... wont be confused with failures to allocate MyClass. Is there a clean, simple solution that I have overlooked? class SomeExtResourceA; class SomeExtResourceB; class MyClass { private: // These resources come out of a resource pool not allocated with "new" for each use by MyClass SomeResourceA* m_resA; SomeResourceB* m_resB; public: MyClass(SomeResourceA* resA, SomeResourceB* resB): m_resA(resA), m_resB(resB) { ABC(); // ... more code here, could throw exceptions } ~MyClass(){ if(m_resA){ m_resA->Release(); } if(m_resB){ m_resB->Release(); } } }; void myFunc(void) { SomeResourceA* resA = NULL; SomeResourceB* resB = NULL; MyClass* pMyInst = NULL; try { resA = g_pPoolA->Allocate(); resB = g_pPoolB->Allocate(); pMyInst = new MyClass(resA,resB); resA=NULL; // ''ownership succesfully transfered to pMyInst resB=NULL; // ''ownership succesfully transfered to pMyInst // Do some work with pMyInst; ...; delete pMyInst; } catch (...) { // cleanup // need to check if resA, or resB were allocated prior // to construction of pMyInst. if(resA) resA->Release(); if(resB) resB->Release(); delete pMyInst; throw; // rethrow caught exception } }

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  • C - What is the proper format to allow a function to show an error was encountered?

    - by BrainSteel
    I have a question about what a function should do if the arguments to said function don't line up quite right, through no fault of the function call. Since that sentence doesn't make much sense, I'll offer my current issue. To keep it simple, here is the most relevant and basic function I have. float getYValueAt(float x, PHYS_Line line, unsigned short* error) *error = 0; if(x < line.start.x || x > line.end.x){ *error = 1; return -1; } if(line.slope.value != 0){ //line's equation: y - line.start.y = line.slope.value(x - line.start.x) return line.slope.value * (x - line.start.x) + line.start.y; } else if(line.slope.denom == 0){ if(line.start.x == x) return line.start.y; else{ *error = 1; return -1; } } else if(line.slope.num == 0){ return line.start.y; } } The function attempts to find the point on a line, given a certain x value. However, under some circumstances, this may not be possible. For example, on the line x = 3, if 5 is passed as a value, we would have a problem. Another problem arises if the chosen x value is not within the interval the line is on. For this, I included the error pointer. Given this format, a function call could work as follows: void foo(PHYS_Line some_line){ unsigned short error = 0; float y = getYValueAt(5, some_line, &error); if(error) fooey(); else do_something_with_y(y); } My question pertains to the error. Note that the value returned is allowed to be negative. Returning -1 does not ensure that an error has occurred. I know that it is sometimes preferred to use the following method to track an error: float* getYValueAt(float x, PHYS_Line line); and then return NULL if an error occurs, but I believe this requires dynamic memory allocation, which seems even less sightly than the solution I was using. So, what is standard practice for an error occurring?

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  • Sort a list of pointers.

    - by YuppieNetworking
    Hello all, Once again I find myself failing at some really simple task in C++. Sometimes I wish I could de-learn all I know from OO in java, since my problems usually start by thinking like Java. Anyways, I have a std::list<BaseObject*> that I want to sort. Let's say that BaseObject is: class BaseObject { protected: int id; public: BaseObject(int i) : id(i) {}; virtual ~BaseObject() {}; }; I can sort the list of pointer to BaseObject with a comparator struct: struct Comparator { bool operator()(const BaseObject* o1, const BaseObject* o2) const { return o1->id < o2->id; } }; And it would look like this: std::list<BaseObject*> mylist; mylist.push_back(new BaseObject(1)); mylist.push_back(new BaseObject(2)); // ... mylist.sort(Comparator()); // intentionally omitted deletes and exception handling Until here, everything is a-ok. However, I introduced some derived classes: class Child : public BaseObject { protected: int var; public: Child(int id1, int n) : BaseObject(id1), var(n) {}; virtual ~Child() {}; }; class GrandChild : public Child { public: GrandChild(int id1, int n) : Child(id1,n) {}; virtual ~GrandChild() {}; }; So now I would like to sort following the following rules: For any Child object c and BaseObject b, b<c To compare BaseObject objects, use its ids, as before. To compare Child objects, compare its vars. If they are equal, fallback to rule 2. GrandChild objects should fallback to the Child behavior (rule 3). I initially thought that I could probably do some casts in Comparator. However, this casts away constness. Then I thought that probably I could compare typeids, but then everything looked messy and it is not even correct. How could I implement this sort, still using list<BaseObject*>::sort ? Thank you

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