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  • Android maps out of memory error

    - by SamB09
    Hi , sometimes when running a google maps program with an overlay image i will receive a bit map out of memory error. It always seems to be at a random point in the app. Im not sure how to solve this. Anyone have any ideas ? My overlay code is below , im not sure if you need to see the class its called in though? public class MyOverlay2 extends Overlay { private static final double MAX_TAP_DISTANCE_KM = 3; // Rough approximation - one degree = 50 nautical miles private static final double MAX_TAP_DISTANCE_DEGREES = MAX_TAP_DISTANCE_KM * 0.5399568 * 50; private final GeoPoint gPoint; private final Context cont; private final int draw; // private final int lat; public MyOverlay2(Context cont, GeoPoint gPoint1, int draw) { // constructor will be called in the userLocation class to draw an overly image this.cont = cont; this.gPoint = gPoint1; this.draw = draw; } @Override public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) { // constructor takes 3 arguments super.draw(canvas, mapView, shadow); // Convert geo coordinates to screen pixels Point screenPoint = new Point(); mapView.getProjection().toPixels(gPoint, screenPoint); //Read the image from the xml resource using a bitmap factory BitmapFactory.Options options=new BitmapFactory.Options(); options.inSampleSize = 1; Bitmap preview_bitmap=BitmapFactory.decodeResource(cont.getResources(),R.drawable.monday12,options); //draw the image at the location specified by the co-ordinates canvas.drawBitmap(preview_bitmap, screenPoint.x - preview_bitmap.getWidth() /2, screenPoint.y - preview_bitmap.getHeight()/2 , null); // get the images height and width values divided by two draw the image at the specified screen points return true; } @Override public boolean onTap(GeoPoint s, MapView mapView) { // Handle tapping on the overlay here return true; } }

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  • vector::erase with pointer member

    - by matt
    I am manipulating vectors of objects defined as follow: class Hyp{ public: int x; int y; double wFactor; double hFactor; char shapeNum; double* visibleShape; int xmin, xmax, ymin, ymax; Hyp(int xx, int yy, double ww, double hh, char s): x(xx), y(yy), wFactor(ww), hFactor(hh), shapeNum(s) {visibleShape=0;shapeNum=-1;}; //Copy constructor necessary for support of vector::push_back() with visibleShape Hyp(const Hyp &other) { x = other.x; y = other.y; wFactor = other.wFactor; hFactor = other.hFactor; shapeNum = other.shapeNum; xmin = other.xmin; xmax = other.xmax; ymin = other.ymin; ymax = other.ymax; int visShapeSize = (xmax-xmin+1)*(ymax-ymin+1); visibleShape = new double[visShapeSize]; for (int ind=0; ind<visShapeSize; ind++) { visibleShape[ind] = other.visibleShape[ind]; } }; ~Hyp(){delete[] visibleShape;}; }; When I create a Hyp object, allocate/write memory to visibleShape and add the object to a vector with vector::push_back, everything works as expected: the data pointed by visibleShape is copied using the copy-constructor. But when I use vector::erase to remove a Hyp from the vector, the other elements are moved correctly EXCEPT the pointer members visibleShape that are now pointing to wrong addresses! How to avoid this problem? Am I missing something?

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  • Access reading error when using class member variable

    - by bsg
    Hi, I have a class with private member variables declared in a header file. In my constructor, I pass in some filenames and create other objects using those names. This works fine. When I try to add another member variable, however, and initialize it in the constructor, I get an access reading violation. I sent the code to someone else and it works fine on his computer. Any idea what could be wrong? Here is the offending code: The .h file: class QUERYMANAGER { INDEXCACHE *cache; URLTABLE *table; SNIPPET *snip; int* iquery[MAX_QUERY_LENGTH]; int* metapointers[MAX_QUERY_LENGTH]; int blockpointers[MAX_QUERY_LENGTH]; int docpositions[MAX_QUERY_LENGTH]; int numberdocs[MAX_QUERY_LENGTH]; int frequencies[MAX_QUERY_LENGTH]; int docarrays[MAX_QUERY_LENGTH][256]; int qsize; public: QUERYMANAGER(); QUERYMANAGER(char *indexfname, char *btfname, char *urltablefname, char *snippetfname, char *snippetbtfname); ~QUERYMANAGER(); This is the .cpp file: #include "querymanagernew.h" #include "snippet.h" using namespace std; QUERYMANAGER::QUERYMANAGER(char *indexfname, char *btfname, char *urltablefname, char *snippetfname, char *snippetbtfname){ cache = new INDEXCACHE(indexfname, btfname); table = new URLTABLE(urltablefname); snip = new SNIPPET(snippetfname, snippetbtfname); //this is where the error occurs qsize = 0; } I am totally at a loss as to what is causing this - any ideas? Thanks, bsg

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  • class header+ implementation

    - by igor
    what am I doing wrong here? I keep on getting a compilation error when I try to run this in codelab (turings craft) Instructions: Write the implementation (.cpp file) of the GasTank class of the previous exercise. The full specification of the class is: A data member named amount of type double. A constructor that no parameters. The constructor initializes the data member amount to 0. A function named addGas that accepts a parameter of type double . The value of the amount instance variable is increased by the value of the parameter. A function named useGas that accepts a parameter of type double . The value of the amount data member is decreased by the value of the parameter. A function named getGasLevel that accepts no parameters. getGasLevel returns the value of the amount data member. class GasTank{ double amount; GasTank(); void addGas(double); void useGas(double); double getGasLevel();}; GasTank::GasTank(){ amount=0;} double GasTank::addGas(double a){ amount+=a;} double GasTank::useGas(double a){ amount+=a;} double GasTank::getGasLevel(){ return amount;}

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  • What do I name this class whose sole purpose is to report failure?

    - by Blair Holloway
    In our system, we have a number of classes whose construction must happen asynchronously. We wrap the construction process in another class that derives from an IConstructor class: class IConstructor { public: virtual void Update() = 0; virtual Status GetStatus() = 0; virtual int GetLastError() = 0; }; There's an issue with the design of the current system - the functions that create the IConstructor-derived classes are often doing additional work which can also fail. At that point, instead of getting a constructor which can be queried for an error, a NULL pointer is returned. Restructuring the code to avoid this is possible, but time-consuming. In the meantime, I decided to create a constructor class which we create and return in case of error, instead of a NULL pointer: class FailedConstructor : public IConstructor public: virtual void Update() {} virtual Status GetStatus() { return STATUS_ERROR; } virtual int GetLastError() { return m_errorCode; } private: int m_errorCode; }; All of the above this the setup for a mundane question: what do I name the FailedConstructor class? In our current system, FailedConstructor would indicate "a class which constructs an instance of Failed", not "a class which represents a failed attempt to construct another class". I feel like it should be named for one of the design patterns, like Proxy or Adapter, but I'm not sure which.

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  • Is a "factory" method the right pattern?

    - by jdt141
    Hey all - So I'm working to improve an existing implementation. I have a number of polymorphic classes that are all composed into a higher level container class. The problem I'm dealing with at the moment is that the higher level container class, well, sucks. It looks something like this, which I really don't have a problem with (as the polymorphic classes in the container should be public). My real issue is the constructor... /* * class1 and class 2 derive from the same superclass */ class Container { public: boost::shared_ptr<ComposedClass1> class1; boost::shared_ptr<ComposedClass2> class2; private: ... } /* * Constructor - builds the objects that we need in this container. */ Container::Container(some params) { class1.reset(new ComposedClass1(...)); class2.reset(new ComposedClass2(...)); } What I really need is to make this container class more re-usable. By hard-coding up the member objects and instantiating them, it basically isn't and can only be used once. A factory is one way to build what I need (potentially by supplying a list of objects and their specific types to be created?) Other ways to get around this problem? Seems like someone should have solved it before... Thanks!

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  • Hibernate NoMethod Error in Java

    - by Noor
    I am getting an error in hibernate and failing to know its origin stack trace: java.lang.NoSuchMethodError: org.hibernate.cfg.AnnotationBinder.bindDefaults(Lorg/hibernate/cfg/Mappings;)V at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1360) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1826) at com.BiddingSystem.server.ServiceImpl.<init>(ServiceImpl.java:60) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at java.lang.Class.newInstance0(Class.java:355) at java.lang.Class.newInstance(Class.java:308) at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153) at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:463) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:324) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395) at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)

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  • Using DTOs and BOs

    - by ryanzec
    One area of question for me about DTOs/BOs is about when to pass/return the DTOs and when to pass/return the BOs. My gut reaction tells me to always map NHibernate to the DTOs, not BOs, and always pass/return the DTOs. Then whenever I needed to perform business logic, I would convert my DTO into a BO. The way I would do this is that my BO would have a have a constructor that takes a parameter that is the type of my interface (that defines the required fields/properties) that both my DTO and BO implement as the only argument. Then I would be able to create my BO by passing it the DTO in the constructor (since both with implement the same interface, they both with have the same properties) and then be able to perform my business logic with that BO. I would then also have a way to convert a BO to a DTO. However, I have also seen where people seem to only work with BOs and only work with DTOs in the background where to the user, it looks like there are no DTOs. What benefits/downfalls are there with this architecture vs always using BO's? Should I always being passing/returning either DTOs or BOs or mix and match (seems like mixing and matching could get confusing)?

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  • [MFC] Creating multiple dialogs in an MFC app with no main Window, they become children of each othe

    - by John
    (title updated) Following on from this question, now I have a clearer picture what's going on... I have a MFC application with no main window, which exposes an API to create dialogs. When I call some of these methods repeatedly, the dialogs created are parented to each other instead of all being parented to the desktop... I have no idea why. But anyway even after creation, I am unable to change the parent back to NULL or CWnd::GetDesktopWindow()... if I call SetParent followed by GetParent, nothing has changed. So apart from the really weird question of why Windows is magically parenting each dialog to the last one created, is there anything I'm missing to be able to set these windows as children of the desktop? UPDATED: I have found the reason for all this, but not the solution. From my dialog constructor, we end up in: BOOL CDialog::CreateIndirect(LPCDLGTEMPLATE lpDialogTemplate, CWnd* pParentWnd, void* lpDialogInit, HINSTANCE hInst) { ASSERT(lpDialogTemplate != NULL); if (pParentWnd == NULL) pParentWnd = AfxGetMainWnd(); m_lpDialogInit = lpDialogInit; return CreateDlgIndirect(lpDialogTemplate, pParentWnd, hInst); } Note: if (pParentWnd == NULL)pParentWnd = AfxGetMainWnd(); The call-stack from my dialog constructor looks like this: mfc80d.dll!CDialog::CreateIndirect(const DLGTEMPLATE * lpDialogTemplate=0x005931a8, CWnd * pParentWnd=0x00000000, void * lpDialogInit=0x00000000, HINSTANCE__ * hInst=0x00400000) mfc80d.dll!CDialog::CreateIndirect(void * hDialogTemplate=0x005931a8, CWnd * pParentWnd=0x00000000, HINSTANCE__ * hInst=0x00400000) mfc80d.dll!CDialog::Create(const char * lpszTemplateName=0x0000009d, CWnd * pParentWnd=0x00000000) mfc80d.dll!CDialog::Create(unsigned int nIDTemplate=157, CWnd * pParentWnd=0x00000000) MyApp.exe!CMyDlg::CMyDlg(CWnd * pParent=0x00000000) Running in the debugger, if I manually change pParentWnd back to 0 in CDialog::CreateIndirect, everything works fine... but how do I stop it happening in the first place?

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  • How to set WS-SecurityPolicy in an inbound CXF service in Mule?

    - by Brakara
    When configuring the service for handling UsernameToken and signatures, it's setup like this: <service name="serviceName"> <inbound> <cxf:inbound-endpoint address="someUrl" protocolConnector="httpsConnector" > <cxf:inInterceptors> <spring:bean class="org.apache.cxf.binding.soap.saaj.SAAJInInterceptor" /> <spring:bean class="org.apache.cxf.ws.security.wss4j.WSS4JInInterceptor"> <spring:constructor-arg> <spring:map> <spring:entry key="action" value="UsernameToken Timestamp Signature" /> <spring:entry key="passwordCallbackRef" value-ref="serverCallback" /> <spring:entry key="signaturePropFile" value="wssecurity.properties" /> </spring:map> </spring:constructor-arg> </spring:bean> </cxf:inInterceptors> </cxf:inbound-endpoint> </inbound> </service> But how is it possible to create a policy of what algorithms that are allowed, and what parts of the message that should be signed?

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  • Can I remove duplicating events in EventAggregator?

    - by Mcad001
    Hi, I have a quite simple scenario that I cannot get to work correctly. I have 2 views, CarView and CarWindowView (childwindow) with corresponding ViewModels. In my CarView I have an EditButton that that opens CarWindowView (childwindow) where I can edit the Car object fields. My problem is that the DisplayModule method in my CarWindowView ViewModel is getting called too many times...When I push the edit button first time its getting called once, the second time its getting called twince, the third time its getting called 3 times and so fort... ! CarView ViewModel constructor: Public Sub New(ByVal eventAggregator As IEventAggregator, ByVal con As IUnityContainer, ByVal mgr As ICarManager, ByVal CarService As ICarService) _Container = con _CarManager = mgr _EventAggregator = eventAggregator 'Create the DelegateCommands NewBtnClick = New DelegateCommand(Of Object)(AddressOf HandleNewCarBtnClick) EditBtnClick = New DelegateCommand(Of Object)(AddressOf HandleEditCarBtnClick) End Sub CarView ViewModel HandleEditCarBtnClick method: Private Sub HandleEditCarBtnClick() Dim view = New CarWindowView Dim viewModel = _Container.Resolve(Of CarWindowViewModel)() viewModel.CurrentDomainContext = DomainContext viewModel.CurrentItem = CurrentItem viewModel.IsEnabled = False view.ApplyModel(viewModel) view.Show() _EventAggregator.GetEvent(Of CarCollectionEvent)().Publish(EditObject) End Sub CarWindowView ViewModel constructor: Public Sub New(ByVal eventAggregator As IEventAggregator, ByVal con As IUnityContainer, ByVal mgr As ICarManager, ByVal CarService As ICarService) _Container = con _CarManager = mgr _EventAggregator = eventAggregator _EventAggregator.GetEvent(Of CarCollectionEvent).Subscribe(AddressOf DisplayModule) End Sub CarWindowView ViewModel DisplayModule method (this is the method getting called too many times): Public Sub DisplayModule(ByVal param As String) If param = EditObject Then IsInEditMode = True ' Logic removed for display reasons here. This logic breaks because it's called too many times. End If End Sub So, I cannot understand how I can only have the EventAggregator to store just the one single click, and not all my click on the Edit button. Sorry if this is not to well explained! Help appreciated!!

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  • Write a program which works out which is the lowest priced computer in an ArrayList of computer obje

    - by Eoin
    Hello everybody! I am trying to study some java and cannot get my head around this question! Any help would be really appreciated and would help me in further studies! Thank you so much in advance! Eoin from Dublin, Ireland. ArrayList of Objects Write a program which works out which is the lowest priced computer in an ArrayList of computer objects. You should have two classes, one called ComputerTest, and the other called Computer. In the ComputerTest class you should: Have a main method which declares an ArrayList of type Computer called computerList, each element of which represents a computer. Initialise the first three entries of the ArrayList Call a static method which prints out the lowest price computer, called lowestPrice The parameter of this method is (i) an ArrayList of type Computer i.e. ArrayList data Sample output: The lowest priced computer is the Cheapo400 at 399 euro. The Computer class should have: Private instance variables: manufacturer, model, price and quality. Quality is a rating from 1 to 10. public get and set methods to retrieve and set/change the value of the four instance variables a default constructor a constructor that takes four parameters

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  • ExternalInterface issue on loadup with FireFox

    - by Rudy
    Hello, I have an issue with my ExternalInterface. The way it is currently set up is, on the page load up, a boolean is set to true in JavaScript and then checked by ActionScript constructors (using a timer) until it is true. This marks that JavaScript is ready to get calls from AS3. At this point, AS3 will add the callback and do some internal stuff, and at the end of the constructor I call JavaScript. So far so good. JavaScript will at this point call a function in AS3 (that was defined in the callback described above), and this is where it all messes up. On IE this works perfectly fine. On FireFox though, it does not. When I debug it, I see that the javascript function is called but when it tries to call AS3, nothing happens. I also tried to add a timer, but for some reason the function STILL executes straight away (in IE). What is very weird is that a second or two later, that function will work, so it seems that the Flash is not completely loaded in FireFox? But it runs to the last line of my constructor, so I would believe it's loaded. Any idea please, I am really stuck. Thanks a lot, Rudy

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  • StructureMap and injecting IEnumerable<T>

    - by GiddyUpHorsey
    I'm new to StructureMap and have some existing code that I'm working with that uses StructureMap 2.5.4. There is a class that is constructed using StructureMap that has a constructor that takes IEnumerable<TCar> as a parameter. The registry has the following code. Scan(x => { x.TheCallingAssembly(); x.WithDefaultConventions(); x.AddAllTypesOf<ICar>(); } ); ForRequestedType<IEnumerable<ICar>>().TheDefault.Is.ConstructedBy( x => ObjectFactory.GetAllInstances<ICar>()); I'm writing a unit test and have obtained a nested container off the ObjectFactory and have injected an instance using the Inject method. One of the instances of ICar should receive the injected type in its constructor. However it wasn't working and I tracked that down to the ObjectFactory.GetAllInstances() call which doesn't use my nested container. How can I get this to work? I also read about StructureMap autowiring arrays and IEnumerable instances but I couldn't get it to work. Is there a better way to rewrite the above registry code so that an instance of IEnumerable<TCar> will be created and use the injected type from my nested container?

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  • c++ queue template

    - by Dalton Conley
    ALright, pardon my messy code please. Below is my queue class. #include <iostream> using namespace std; #ifndef QUEUE #define QUEUE /*---------------------------------------------------------------------------- Student Class # Methods # Student() // default constructor Student(string, int) // constructor display() // out puts a student # Data Members # Name // string name Id // int id ----------------------------------------------------------------------------*/ class Student { public: Student() { } Student(string iname, int iid) { name = iname; id = iid; } void display(ostream &out) const { out << "Student Name: " << name << "\tStudent Id: " << id << "\tAddress: " << this << endl; } private: string name; int id; }; // define a typedef of a pointer to a student. typedef Student * StudentPointer; template <typename T> class Queue { public: /*------------------------------------------------------------------------ Queue Default Constructor Preconditions: none Postconditions: assigns default values for front and back to 0 description: constructs a default empty Queue. ------------------------------------------------------------------------*/ Queue() : myFront(0), myBack(0) {} /*------------------------------------------------------------------------ Copy Constructor Preconditions: requres a reference to a value for which you are copying Postconditions: assigns a copy to the parent Queue. description: Copys a queue and assigns it to the parent Queue. ------------------------------------------------------------------------*/ Queue(const T & q) { myFront = myBack = 0; if(!q.empty()) { // copy the first node myFront = myBack = new Node(q.front()); NodePointer qPtr = q.myFront->next; while(qPtr != NULL) { myBack->next = new Node(qPtr->data); myBack = myBack->next; qPtr = qPtr->next; } } } /*------------------------------------------------------------------------ Destructor Preconditions: none Postconditions: deallocates the dynamic memory for the Queue description: deletes the memory stored for a Queue. ------------------------------------------------------------------------*/ ~Queue() { NodePointer prev = myFront, ptr; while(prev != NULL) { ptr = prev->next; delete prev; prev = ptr; } } /*------------------------------------------------------------------------ Empty() Preconditions: none Postconditions: returns a boolean value. description: returns true/false based on if the queue is empty or full. ------------------------------------------------------------------------*/ bool empty() const { return (myFront == NULL); } /*------------------------------------------------------------------------ Enqueue Preconditions: requires a constant reference Postconditions: allocates memory and appends a value at the end of a queue description: ------------------------------------------------------------------------*/ void enqueue(const T & value) { NodePointer newNodePtr = new Node(value); if(empty()) { myFront = myBack = newNodePtr; newNodePtr->next = NULL; } else { myBack->next = newNodePtr; myBack = newNodePtr; newNodePtr->next = NULL; } } /*------------------------------------------------------------------------ Display Preconditions: requires a reference of type ostream Postconditions: returns the ostream value (for chaining) description: outputs the contents of a queue. ------------------------------------------------------------------------*/ void display(ostream & out) const { NodePointer ptr; ptr = myFront; while(ptr != NULL) { out << ptr->data << " "; ptr = ptr->next; } out << endl; } /*------------------------------------------------------------------------ Front Preconditions: none Postconditions: returns a value of type T description: returns the first value in the parent Queue. ------------------------------------------------------------------------*/ T front() const { if ( !empty() ) return (myFront->data); else { cerr << "*** Queue is empty -- returning garbage value ***\n"; T * temp = new(T); T garbage = * temp; delete temp; return garbage; } } /*------------------------------------------------------------------------ Dequeue Preconditions: none Postconditions: removes the first value in a queue ------------------------------------------------------------------------*/ void dequeue() { if ( !empty() ) { NodePointer ptr = myFront; myFront = myFront->next; delete ptr; if(myFront == NULL) myBack = NULL; } else { cerr << "*** Queue is empty -- " "can't remove a value ***\n"; exit(1); } } /*------------------------------------------------------------------------ pverloaded = operator Preconditions: requires a constant reference Postconditions: returns a const type T description: this allows assigning of queues to queues ------------------------------------------------------------------------*/ Queue<T> & operator=(const T &q) { // make sure we arent reassigning ourself // e.g. thisQueue = thisQueue. if(this != &q) { this->~Queue(); if(q.empty()) { myFront = myBack = NULL; } else { myFront = myBack = new Node(q.front()); NodePointer qPtr = q.myFront->next; while(qPtr != NULL) { myBack->next = new Node(qPtr->data); myBack = myBack->next; qPtr = qPtr->next; } } } return *this; } private: class Node { public: T data; Node * next; Node(T value, Node * first = 0) : data(value), next(first) {} }; typedef Node * NodePointer; NodePointer myFront, myBack, queueSize; }; /*------------------------------------------------------------------------ join Preconditions: requires 2 queue values Postconditions: appends queue2 to the end of queue1 description: this function joins 2 queues into 1. ------------------------------------------------------------------------*/ template <typename T> Queue<T> join(Queue<T> q1, Queue<T> q2) { Queue<T> q1Copy(q1), q2Copy(q2); Queue<T> jQueue; while(!q1Copy.empty()) { jQueue.enqueue(q1Copy.front()); q1Copy.dequeue(); } while(!q2Copy.empty()) { jQueue.enqueue(q2Copy.front()); q2Copy.dequeue(); } cout << jQueue << endl; return jQueue; } /*---------------------------------------------------------------------------- Overloaded << operator Preconditions: requires a constant reference and a Queue of type T Postconditions: returns the ostream (for chaining) description: this function is overloaded for outputing a queue with << ----------------------------------------------------------------------------*/ template <typename T> ostream & operator<<(ostream &out, Queue<T> &s) { s.display(out); return out; } /*---------------------------------------------------------------------------- Overloaded << operator Preconditions: requires a constant reference and a reference of type Student Postconditions: none description: this function is overloaded for outputing an object of type Student. ----------------------------------------------------------------------------*/ ostream & operator<<(ostream &out, Student &s) { s.display(out); } /*---------------------------------------------------------------------------- Overloaded << operator Preconditions: requires a constant reference and a reference of a pointer to a Student object. Postconditions: none description: this function is overloaded for outputing pointers to Students ----------------------------------------------------------------------------*/ ostream & operator<<(ostream &out, StudentPointer &s) { s->display(out); } #endif Now I'm having some issues with it. For one, when I add 0 to a queue and then I output the queue like so.. Queue<double> qdub; qdub.enqueue(0); cout << qdub << endl; That works, it will output 0. But for example, if I modify that queue in any way.. like.. assign it to a different queue.. Queue<double> qdub1; Queue<double> qdub2; qdub1.enqueue(0; qdub2 = qdub1; cout << qdub2 << endl; It will give me weird values for 0 like.. 7.86914e-316. Help on this would be much appreciated!

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  • In Java it seems Public constructors are always a bad coding practice

    - by Adam Gent
    This maybe a controversial question and may not be suited for this forum (so I will not be insulted if you choose to close this question). It seems given the current capabilities of Java there is no reason to make constructors public ... ever. Friendly, private, protected are OK but public no. It seems that its almost always a better idea to provide a public static method for creating objects. Every Java Bean serialization technology (JAXB, Jackson, Spring etc...) can call a protected or private no-arg constructor. My questions are: I have never seen this practice decreed or written down anywhere? Maybe Bloch mentions it but I don't own is book. Is there a use case other than perhaps not being super DRY that I missed? EDIT: I explain why static methods are better. .1. For one you get better type inference. For example See Guava's http://code.google.com/p/guava-libraries/wiki/CollectionUtilitiesExplained .2. As a designer of the class you can later change what is returned with a static method. .3. Dealing with constructor inheritance is painful especially if you have to pre-calculate something.

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  • Problems initializing a final variable in Java

    - by froadie
    I keep running into slight variations of a problem in Java and it's starting to get to me, and I can't really think of a proper way to get around it. I have an object property that is final, but dynamic. That is, I want the value to be constant once assigned, but the value can be different each runtime. So I declare the class level variable at the beginning of the class - say private final FILE_NAME;. Then, in the constructor, I assign it a value - say FILE_NAME = buildFileName(); The problem begins when I have code in the buildFileName() method that throws an exception. So I try something like this in the constructor: try{ FILE_NAME = buildFileName(); } catch(Exception e){ ... System.exit(1); } Now I have an error - "The blank final field FILE_NAME may not have been initialized." This is where I start to get slightly annoyed at Java's strict compiler. I know that this won't be a problem because if it gets to the catch the program will exit... But the compiler doesn't know that and so doesn't allow this code. If I try to add a dummy assignment to the catch, I get - "The final field FILE_NAME may already have been assigned." I clearly can't assign a default value before the try-catch because I can only assign to it once. Any ideas...?

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  • How to initialize audio with Vala/SDL

    - by ioev
    I've been trying to figure this out for a few hours now. In order to start up the audio, I need to create an SDL.AudioSpec object and pass it to SDL.Audio.Open. The problem is, AudioSpec is a class with a private constructor, so when I try to create one I get: sdl.vala:18.25-18.43: error: `SDL.AudioSpec' does not have a default constructor AudioSpec audiospec = new SDL.AudioSpec(); ^^^^^^^^^^^^^^^^^^^ And if I try to just assign values to it's member vars like a struct (it's a struct in normal sdl) I get: sdl.vala:20.3-20.25: error: use of possibly unassigned local variable `audiospec' audiospec.freq = 22050; ^^^^^^^^^^^^^^^^^^^^^^^ I found the valac doc here: http://valadoc.org/sdl/SDL.AudioSpec.html But it isn't much help at all. The offending code block looks like this: // setup the audio configuration AudioSpec audiospec; AudioSpec specback; audiospec.freq = 22050; audiospec.format = SDL.AudioFormat.S16LSB; audiospec.channels = 2; audiospec.samples = 512; // try to initialize sound with these values if (SDL.Audio.open(audiospec, specback) < 0) { stdout.printf("ERROR! Check audio settings!\n"); return 1; } Any help would be greatly appreciated!

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  • C# creating a Class, having objects as member variables? I think the objects are garbage collecte

    - by Bryan
    So I have a class that has the following member variables. I have get and set functions for every piece of data in this class. public class NavigationMesh { public Vector3 node; int weight; bool isWall; bool hasTreasure; public NavigationMesh(int x, int y, int z, bool setWall, bool setTreasure) { //default constructor //Console.WriteLine(x + " " + y + " " + z); node = new Vector3(x, y, z); //Console.WriteLine(node.X + " " + node.Y + " " + node.Z); isWall = setWall; hasTreasure = setTreasure; weight = 1; }// end constructor public float getX() { Console.WriteLine(node.X); return node.X; } public float getY() { Console.WriteLine(node.Y); return node.Y; } public float getZ() { Console.WriteLine(node.Z); return node.Z; } public bool getWall() { return isWall; } public void setWall(bool item) { isWall = item; } public bool getTreasure() { return hasTreasure; } public void setTreasure(bool item) { hasTreasure = item; } public int getWeight() { return weight; } }// end class In another class, I have a 2-Dim array that looks like this NavigationMesh[,] mesh; mesh = new NavigationMesh[502,502]; I use a double for loop to assign this, my problem is I cannot get the data I need out of the Vector3 node object after I create this object in my array with my "getters". I've tried making the Vector3 a static variable, however I think it refers to the last instance of the object. How do I keep all of these object in memory? I think there being garbage collected. Any thoughts?

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  • Javascript function using "this = " gives "Invalid left-hand side in assignment"

    - by Brian M. Hunt
    I am trying to get a Javascript object to use the "this" assignments of another objects' constructor, as well as assume all that objects' prototype functions. Here's an example of what I'm attempting to accomplish: /* The base - contains assignments to 'this', and prototype functions */ function ObjX(a,b) { this.$a = a, $b = b; } ObjX.prototype.getB() { return this.$b; } function ObjY(a,b,c) { // here's what I'm thinking should work: this = ObjX(a, b * 12); /* and by 'work' I mean ObjY should have the following properties: * ObjY.$a == a, ObjY.$b == b * 12, * and ObjY.getB() == ObjX.prototype.getB() * ... unfortunately I get the error: * Uncaught ReferenceError: Invalid left-hand side in assignment */ this.$c = c; // just to further distinguish ObjY from ObjX. } I'd be grateful for your thoughts on how to have ObjY subsume ObjX's assignments to 'this' (i.e. not have to repeat all the this.$* = * assignments in ObjY's constructor) and have ObjY assume ObjX.prototype. My first thought is to try the following: function ObjY(a,b,c) { this.prototype = new ObjX(a,b*12); } Ideally I'd like to learn how to do this in a prototypal way (i.e. not have to use any of those 'classic' OOP substitutes like Base2). It may be noteworthy that ObjY will be anonymous (e.g. factory['ObjX'] = function(a,b,c) { this = ObjX(a,b*12); ... }) -- if I've the terminology right. Thank you.

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  • Create an instance of an exported C++ class from Delphi

    - by Alan G.
    I followed an excellent article by Rudy Velthuis about using C++ classes in DLL's. Everything was golden, except that I need access to some classes that do not have corresponding factories in the C++ DLL. How can I construct an instance of a class in the DLL? The classes in question are defined as class __declspec(dllexport) exampleClass { public: void foo(); }; Now without a factory, I have no clear way of instantiating the class, but I know it can be done, as I have seen SWIG scripts (.i files) that make these classes available to Python. If Python&SWIG can do it, then I presume/hope there is some way to make it happen in Delphi too. Now I don't know much about SWIG, but it seems like it generates some sort of map for C++ mangled names? Is that anywhere near right? Looking at the exports from the DLL, I suppose I could access functions & constructor/destructor by index or the mangled name directly, but that would be nasty; and would it even work? Even if I can call the constructor, how can I do the equivalent of "new CClass();" in Delphi?

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  • What is the Proper approach for Constructing a PhysicalAddress object from Byte Array

    - by Paul Farry
    I'm trying to understand what the correct approach for a constructor that accepts a Byte Array with regard to how it stores it's data (specifically with PhysicalAddress) I have an array of 6 bytes (theAddress) that is constructed once. I have a source array of 18bytes (theAddresses) that is loaded from a TCP Connection. I then copy the 6bytes from theAddress+offset into theAddress and construct the PhysicalAddress from it. Problem is that the PhysicalAddress just stores the Reference to the array that was passed in. Therefore if you subsequently check the addresses they only ever point to the last address that was copied in. When I took a look inside the PhysicalAddress with reflector it's easy to see what's going on. public PhysicalAddress(byte[] address) { this.changed = true; this.address = address; } Now I know this can be solved by creating theAddress array on each pass, but I wanted to find out what really is the best practice for this. Should the constructor of an object that accepts a byte array create it's own private Variable for holding the data and copy it from the original Should it just hold the reference to what was passed in. Should I just created theAddress on each pass in the loop

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  • Is this a good decorator pattern for javascript?

    - by Kucebe
    I need some simple objects that could become more complex later, with many different properties, so i thought to decorator pattern. I made this looking at Crockford's power constructor and object augmentation: //add property to object Object.prototype.addProperty = function(name, func){ for(propertyName in this){ if(propertyName == name){ throw new Error(propertyName + " is already defined"); } } this[name] = func; }; //constructor of base object var BaseConstructor = function(param){ var _privateVar = param; return{ getPrivateVar: function(){ return _privateVar; } }; }; //a simple decorator, adds one private attribute and one privileged method var simpleDecorator = function(obj, param){ var _privateVar = param; var privilegedMethod1 = function(){ return "privateVar of decorator is: " + _privateVar; }; obj.addProperty("privilegedMethod1", privilegedMethod1); return obj; } //a more complex decorator, adds public and private properties var complexDecorator = function(obj, param1, param2){ //private properties var _privateVar = param1; var _privateMethod = function(x){ for(var i=0; i<x; i++){ _privateVar += x; } return _privateVar; }; //public properties var publicVar = "I'm public"; obj.addProperty("publicVar", publicVar); var privilegedMethod2 = function(){ return _privateMethod(param2); }; obj.addProperty("privilegedMethod2", privilegedMethod2); var publicMethod = function(){ var temp = this.privilegedMethod2(); return "do something: " + temp + " - publicVar is: " + this.publicVar; }; obj.addProperty("publicMethod", publicMethod); return obj; } //new basic object var myObj = BaseConstructor("obj1"); //the basic object will be decorated var myObj = simpleDecorator(obj, "aParam"); //the basic object will be decorated with other properties var myObj = complexDecorator(obj, 2, 3); Is this a good way to have Decorator Pattern in javascript? Are there other better ways to do this?

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  • Why are my connections not closed even if I explicitly dispose of the DataContext?

    - by Chris Simpson
    I encapsulate my linq to sql calls in a repository class which is instantiated in the constructor of my overloaded controller. The constructor of my repository class creates the data context so that for the life of the page load, only one data context is used. In my destructor of the repository class I explicitly call the dispose of the DataContext though I do not believe this is necessary. Using performance monitor, if I watch my User Connections count and repeatedly load a page, the number increases once per page load. Connections do not get closed or reused (for about 20 minutes). I tried putting Pooling=false in my config to see if this had any effect but it did not. In any case with pooling I wouldn't expect a new connection for every load, I would expect it to reuse connections. I've tried putting a break point in the destructor to make sure the dispose is being hit and sure enough it is. So what's happening? Some code to illustrate what I said above: The controller: public class MyController : Controller { protected MyRepository rep; public MyController () { rep = new MyRepository(); } } The repository: public class MyRepository { protected MyDataContext dc; public MyRepository() { dc = getDC(); } ~MyRepository() { if (dc != null) { //if (dc.Connection.State != System.Data.ConnectionState.Closed) //{ // dc.Connection.Close(); //} dc.Dispose(); } } // etc } Note: I add a number of hints and context information to the DC for auditing purposes. This is essentially why I want one connection per page load

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  • JavaEE: Question about design

    - by Harry Pham
    I have a JSF page that will create a new Comment. I have the managed bean of that page to be RequestScoped managed bean. @ManagedBean(name="PostComment") @RequestScoped public class PostComment { private Comment comment = null; @ManagedProperty(value="#{A}") private A a; //A is a ViewScoped Bean @ManagedProperty(value="#{B}") private B b; //B is a ViewScoped Bean @PostConstruct public void init(){ comment = new Comment(); } // setters and getters for comment and all the managed property variable public void postComment(String location){ //persist the new comment ... if(location.equals("A")){ //update the comment list on page A }else if(location.equals("B")){ //update the comment list on page B } } } As you can see from the code above, 2 ViewScoped bean A and B will both use method postComment(), and getter getComment() from bean PostComment. The problem I am having right now is that, if I am on A, constructor of A will load, but it will also load constructor of bean B. This make my page load twice as slow. What would be the best way to solve this problem?

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