Search Results

Search found 54446 results on 2178 pages for 'struct vs class'.

Page 767/2178 | < Previous Page | 763 764 765 766 767 768 769 770 771 772 773 774  | Next Page >

  • C++ template typedef

    - by Notinlist
    I have a class template<size_t N, size_t M> class Matrix { // .... }; I want to make a typedef which creates a Vector (column vector) which is equivalent to a Matrix with sizes N and 1. Something like that: typedef Matrix<N,1> Vector<N>; Which produces compile error. The following creates something similar, but not exactly what I want: template <int N> class Vector: public Matrix<N,1> { }; Is there a solution or a not too expensive workaround / best-practice for it? Thanks in advance!

    Read the article

  • jQuery .parent() does not work

    - by Misha Moroshko
    Why the following code fails with: Error: class_a_jquery_objects[0].parent is not a function ? HTML: <div> <div class='a b'></div> <div class='b c'></div> <div class='c a'></div> </div> <div id='log'></div> JS: $(function() { var class_a_jquery_objects = $(".a"); $("#log").append(class_a_jquery_objects.length + "<br />"); $("#log").append(class_a_jquery_objects[0] + "<br />"); $("#log").append(class_a_jquery_objects[0].parent() + "<br />"); });

    Read the article

  • Forbid public Add and Delete for a List<T>

    - by aaginor
    Hi folks, in my C#-project, I have a class which contains a List public class MyClass { public MyClass parent; public List<MyClass> children; ... } I want to prevent the user of the class from Adding (and Deleting) an Element to the children-List, but he shall still be able to parse its elements. I want to handle the Adding and Deleting within MyClass, providing an AddChild(MyClass item) and DeleteChild(MyClass item) to ensure that, when an item is added to the child list, the parent of that item will be set properly. Any idea how to do this besides implementing my own IList? Thanks in advance, Frank

    Read the article

  • Possible for C++ template to check for a function's existence?

    - by andy
    Is it possible to write a C++ template that changes behavior depending on if a certain member function is defined on a class? Here's a simple example of what I would want to write: template<class T> std::string optionalToString(T* obj) { if (FUNCTION_EXISTS(T->toString)) return obj->toString(); else return "toString not defined"; } So if class T has "toString" defined then it uses it, otherwise it doesn't. The magical part that I don't know how to do is the "FUNCTION_EXISTS" part.

    Read the article

  • Inheritance: possible to change base reference to something else?

    - by fred
    For example I have two classes, Base and Derived as shown below: class Base { public string Name { get; set; } public Base() { } } class Derived : Base { public Derived(Base b) { base = b; // doesn't compile, but is there any way to do something similar? } } So that they behave like this: Base b = new Base(); b.Name = "Bob"; Derived d = new Derived(b); d.Name = "John"; // b.Name is now "John" also Is this possible? I guess one way would be to keep the Base b reference in Derived and override Derived.Name to point to b.Name? Is there an easier way though, for example if I have like 50 properties to override? class Derived : Base { Base b; public override string Name { get { return b.Name; } set { b.Name = value; } } public Derived(Base b) { this.b = b; } }

    Read the article

  • Hibernate - why use many-to-one to represent a one-to-one?

    - by aberrant80
    I've seen people use many-to-one mappings to represent one-to-one relationships. I've also read this in a book by Gavin King and on articles. For example, if a customer can have exactly one shipping address, and a shipping address can belong to only one customer, the mapping is given as: <class name="Customer" table="CUSTOMERS"> ... <many-to-one name="shippingAddress" class="Address" column="SHIPPING_ADDRESS_ID" cascade="save-update" unique="true"/> ... </class> The book reasons as (quoting it): "You don't care what's on the target side of the association, so you can treat it like a to-one association without the many part." My question is, why use many-to-one and not one-to-one? What is it about a one-to-one that makes it a less desirable option to many-to-one? Thanks.

    Read the article

  • C programming: hashtable insertion/search

    - by Ricardo Campos
    Hello i have a problem with my hash table its implemented like this: #define HT_SIZE 10 typedef struct _list_t_ { char key[20]; char string[20]; char prevValue[20]; struct _list_t_ *next; } list_t; typedef struct _hash_table_t_ { int size; /* the size of the table */ list_t ***table; /* first */ sem_t lock; } hash_table_t; I have a Linked list with 3 pointers because i want a hash table with several partitions (shards), here is my initialization of my Hash table: hash_table_t *create_hash_table(int NUM_SERVER_THREADS, int num_shards){ hash_table_t *new_table; int j,i; if (HT_SIZE<1) return NULL; /* invalid size for table */ /* Attempt to allocate memory for the hashtable structure */ new_table = (hash_table_t*)malloc(sizeof(hash_table_t)*HT_SIZE); /* Attempt to allocate memory for the table itself */ new_table->table = (list_t ***)calloc(1,sizeof(list_t **)); /* Initialize the elements of the table */ for(j=0; j<num_shards; j++){ new_table->table[j] = (list_t **)calloc(1,sizeof(list_t *)); for(i=0; i<HT_SIZE; i++){ new_table->table[j][i] = (list_t *)calloc(1,sizeof(list_t )); } } /* Set the table's size */ new_table->size = HT_SIZE; sem_init(&new_table->lock, 0, 1); return new_table; } Here is my search function to search in the hash table list_t *lookup_string(hash_table_t *hashtable, char *key, int shardId){ list_t *list ; int hashval = hash(key); /* Go to the correct list based on the hash value and see if key is * in the list. If it is, return return a pointer to the list element. * If it isn't, the item isn't in the table, so return NULL. */ sem_wait(&hashtable->lock); for(list = hashtable->table[shardId][hashval]; list != NULL; list =list->next) { if (strcmp(key, list->key) == 0){ sem_post(&hashtable->lock); return list; } } sem_post(&hashtable->lock); return NULL; } And my insert function: char *add_string(hash_table_t *hashtable, char *str,char *key, int shardId){ list_t *new_list; list_t *current_list; unsigned int hashval = hash(key); /*printf("|%d|%d|%s|\n",hashval,shardId,key);*/ /* Lock for concurrency */ sem_wait(&hashtable->lock); /* Attempt to allocate memory for list */ new_list = (list_t*)malloc(sizeof(list_t)); /* Does item already exist? */ sem_post(&hashtable->lock); current_list = lookup_string(hashtable, key,shardId); sem_wait(&hashtable->lock); /* item already exists, don't insert it again. */ if (current_list != NULL){ strcpy(new_list->prevValue,current_list->string); strcpy(new_list->string,str); strcpy(new_list->key,key); new_list->next = hashtable->table[shardId][hashval]; hashtable->table[shardId][hashval] = new_list; sem_post(&hashtable->lock); return new_list->prevValue; } /* Insert into list */ strcpy(new_list->string,str); strcpy(new_list->key,key); new_list->next = hashtable->table[shardId][hashval]; hashtable->table[shardId][hashval] = new_list; /* Unlock */ sem_post(&hashtable->lock); return new_list->prevValue; } My main class runs some of tests by executing the insertion / reading / delete from the elements of the hash table the problem is when i have more than 4 partitions/shards the tests stop at the first reading element saying it returned the wrong value NULL on the search function, when its less than 4 it runs perfectly well and passes all the tests. You can see my main.c in here if you want to give a look: http://hostcode.sourceforge.net/view/1105 My complete Hash table code: http://hostcode.sourceforge.net/view/1103 And other functions where hash table code is executed: .c file http://hostcode.sourceforge.net/view/1104 .h file http://hostcode.sourceforge.net/view/1106 Thank for you time, i appreciate any help you can give to me this is a college important project that I'm trying to solve and I'm stuck here for 2 days.

    Read the article

  • NHibernate FetchMode

    - by Sandra
    Hi All, I have an object Parent which has a list of Children: class Parent {Id, Name, IList children} class Child {Id, Name} I need to select all parents where there is a condition for their children but I do not want to get duplicate rows (don't want the children details to appear in select list) Here is the code: session.CreateCriteria(typeof(Parent)) .SetFetchMode("children", FetchMode.Select); .CreateCriteria("children").Add(Subqueries.PropertyIn("Id", {1,2,3,4})) .List(); The query adds all proprties of child class to select list which results in duplicate Parents. Is there any way I can select all parents without having the child details in the select list? Thanks

    Read the article

  • Get other classes from an element with Jquery

    - by Jigs
    I am working on a small bit of script that will allow for easy and flexible creation of buttons. My buttons are made of three parts, a left, a right and a streched middle piece. There are three different sizes and three different colours of each. I have written the code that resizes the button to fit the text. Now I am looking to add the ability to easily set the colour and size. I was thinking of using three classes something like <div class="button blue big"> My script already loops through the button classes using each. Now I need to find out what other classes are set and adjust the pictures and dimentions used to fit. So how can I find out what other class selectors an element has? Also I am fairly new to jquery/javascript so I am wondering if storing the design as class selectors is the best way.

    Read the article

  • How are value types implemented in .NET

    - by Michael
    Been looking around the net and can't find any articles about how value types are actually implemented. For instance, an Int32 is a struct and it's direct parent is System.ValueType and that's ultimate parent is System.Object. Object is a class - I imagine ValueType is a class? What's the class hierarchy? What part does the CLR have to play? At what stage and how does the CLR know to allocate value types to the stack? (FYI, I am aware that value types are stored where they are declared).

    Read the article

  • Should we avoid to use Object as the input parameter/ output value of a method?

    - by developer.cyrus
    Take Java syntax as an example, though the question itself is language independent. If the following snippet takes an object MyAbstractEmailTemplate as input argument in the method setTemplate, the class MyGateway will then become tightly-coupled with the object MyAbstractEmailTemplate, which lessens the re-usability of the class MyGateway. A compromise is to use dependency-injection to ease the instantiation of MyAbstractEmailTemplate. This might solve the coupling problem to some extent, but the interface is still rigid, hardly providing enough ?exibility to other developers/ applications. So if we only use primitive data type (or even plain XML in web service) as the input/ output of a method, it seems the coupling problem no longer exists. So what do you think? public class MyGateway { protected MyAbstractEmailTemplate template; publoc void setTemplate(MyAbstractEmailTemplate template) { this.template = template; } }

    Read the article

  • .replace method in jquery

    - by amit
    i want to replace class me to old when user clicks on a tag, i want to do that only with .replace function. My purpose to learn how replace method work. But the function which i have made not working. <head> <script type="text/javascript" src="jquery-1.7.2.js"></script> <script type="text/javascript"> $(function(){ $('a').click(function(){ $(this).attr('class').replace('me','old') }) }) </script> </head> <body> <a href="#" class="me">click</a> </body>

    Read the article

  • Beginning with Datampper, Association question

    - by Ian
    I'm just diving into Datamapper (and Sinatra) and have a question about associations. Below are some models I have. This is what I want to implemented. I'm having an issue with Workoutitems and Workout. Workout will be managed separately, but Workoutitems has a single workout associated with each row. Workout - just a list of types of workouts (run, lift, situps, etc) Selected workout - this is the name of a set of workouts, along with notes by the user and trainer. It has a collection of N workoutitems Workoutitems - this takes a workout and a number of repetitions to it that go in the workout set. class Workout include DataMapper::Resource property :id, Serial #PK id property :name, String, :length=50,:required=true # workout name property :description, String, :length=255 #workout description end class Selectedworkout include DataMapper::Resource property :id, Serial property :name, String, :length=50, :required=true property :workout_time, String, :length=20 property :user_notes, String, :length=255 property :coach_notes, String, :length=255 has n, :workoutitems end class Workoutitem include DataMapper::Resource property :id, Serial property :reps, String, :length=50, :required=true belongs_to :selectedworkout end

    Read the article

  • Passing an array argument from C# to a C++/CLI method

    - by jco
    I know only very little about C++/CLI, but I have a simple problem that needs a solution. I have a C++/CLI class method that takes a byte-array as a parameter. The array is of a pre-determined length, and can be allocated in C# beforehand. The array is supposed to be filled with data by the C++/CLI method. How do I declare the method and then call it from C#? I tried something like having the following in my C++/CLI class: public ref class C { public: void FillBytes(array<BYTE^>^ bytes); }; And then, in C#: o = new C(); var bytes = new byte[3]; o.FillBytes(bytes); But that didn't work at all :).

    Read the article

  • maintain user login status in express.js

    - by chenliang
    when user login the app the username will be display in the header, this is my header.jade div#header_content input(type='text',name='search',id='globle_search') span#user_status if(req.isAuthenticated()) a(class='user_menu_btn',href='home', target='_blank' ) req.user.username a(class='user_menu_btn',href='logout') Logout else a(id='login_btn',href='login',class='user_status_btn') login run the app i get the error says ReferenceError: F:\shopping\views\includes\header.jade:4 req is not defined this is my index route: app.get('/',index.index); exports.index = function(req, res){ res.render('index', { title: 'Express' }); }; how to maintain login ststus in the heaedr? by the way am using passport to login user

    Read the article

  • C++ Why is the copy constructor implicitly called?

    - by ShaChris23
    Why is the Child class's copy constructor called in the code below? I mean, it automatically converts Base to Child via the Child copy constructor. The code below compiles, but shouldn't it not compile since I haven't provided bool Child::operator!=(Base const&)? class Base { }; class Child : public Base { public: Child() {} Child(Base const& base_) : Base(base_) { std::cout <<"should never called!"; } bool operator!=(Child const&) { return true; } }; void main() { Base base; Child child; if(child != base) std::cout << "not equal"; else std::cout << "equal"; }

    Read the article

  • Beginner questions regarding Python classes.

    - by Andy
    Hi. I am new to Python so please don't flame me if I ask something too noobish :) 1. Consider I have a class: class Test: def __init__(self, x, y): self.x = x self.y = y def wow(): print 5 * 5 Now I try to create an object of the class: x = Test(3, 4) This works as expected. However, when I try to call the method wow(), it returns an error, which is fixed by changing wow() to: def wow(self) Why do I need to include self and if I don't, what does the method mean?2. In the definition of __init__: def __init__(self, x, y): self.x = x self.y = y Why do I need to declare x and y, when I can do this: def __init__(self): self.x = x self.y = y I hope I am being clear... Thanks for your time.

    Read the article

  • going to build a php MVC, what naming conventions do i need to be aware of?

    - by Haroldo
    I'm pretty new to OO PHP, however i get how it all works and am ready to start building an MVC for a big site i'm working on. I know it isnt necessary written that you must do it like this but there's gotta be some normal practises.... class names - camelcase? underscores? class files - same as class? url/post/get controll name - router.php? any other things i should be aware of before i embark?

    Read the article

  • Hold border and Resize two or more DIV simultaneously in the same container

    - by Manu
    Code : <div id="widget1"> <div class="part blue">this is the part</div> <div class="part white">of the genial</div> <div class="part red">and good widget</div> </div> Let's say that div#widget1 is 99px width and div.part are 33px by default. How can I easily resize div.blue by increasing its width and deacreasing width of other div.part proportionnaly ? http://jqueryui.com/demos/resizable/#synchronous-resize : give an example which show element increase in the same time. Thanks,

    Read the article

  • Question about a possible design pattern...

    - by Aftershock
    I have such a design in my mind.... My aim is to reuse the program with some features included and without some features. What is it called in the literature? class feature1 { void feature1function1(); void feature1function2(); } class feature2 { void feature2function1(); void feature2function2(); } class program: feature1, feature2 { void function1() { feature2function1(); } void function2() { feature1function1(); feature2function1(); } void execute() { function1(); function2(); } }

    Read the article

  • How is inheritance implemented at the memory level?

    - by cambr
    Suppose I have class A { public: void print(){cout<<"A"; }}; class B: public A { public: void print(){cout<<"B"; }}; class C: public C { }; How is inheritance implemented at the memory level? Does C copy print() code to itself or does it have a pointer to the it that points somewhere in A part of the code? How does the same thing happen when we override the previous definition, for example in B (at the memory level)?

    Read the article

  • How do I reference the other object in django models

    - by UserZero
    Hi, first post here.In Django, I want to have many files be associated with a particular model, so I'm doing a seperate model called files and have model 'A' 'have many' files. But I want my files to be saved in director named by model 'A'. So For example I want something like this: class Show(models.Model): name = models.CharField() showfolder = models.FilePathField() class Episode(models.Model): show = models.ForeignKey(Show) name = models.CharField() files = models.ManyToManyField(mp3) class Mp3(models.Model): file = FileField(upload_to=Episode.show.showfolder) So hopefully that last line expresses what I WANT it to do(get the folder name from Show object associated with the episode). The question is how would I really write that?(besides jumping through hoops in the controller.) Thanks.

    Read the article

  • non-scalar type requested

    - by lego69
    can somebody please help me with an error conversion from `A' to non-scalar type `B' requested I have class A and derived from it B, but I have problems with these rows: A a(1); A *pb = new B(a); B b = *pb; //here I have an error thanks in advance for any help class A { protected: int player; public: A(int initPlayer = 0); A(const A&); A& operator=(const A&); virtual ~A(){}; virtual void foo(); void foo() const; operator int(); }; class B: public A { public: B(int initPlayer): A(initPlayer){}; ~B(){}; virtual void foo(); };

    Read the article

  • Push html attribute to array onClick

    - by Hunkeone
    I'm trying to push number attribute of the element to the array onclick with a simple function, but array contains only empty values separated with commas. Here's html code. <button type="button" class="btn btn-success btn-lg" number="12" onclick="basket.push(this.number)">toBakset</button> <button type="button" class="btn btn-success btn-lg" number="15" onclick="basket.push(this.number)">toBakset</button> <button type="button" class="btn btn-success btn-lg" number="18" onclick="basket.push(this.number)">toBakset</button> from the start "basket" array is empty. Seems this question is so dumb but I can't find a solution :(

    Read the article

  • Inconsistent Behavior From Declared DLL Function

    - by Steven
    Why might my GetRawData declared function return a correct value when called from my VB.NET application, but return zero when called from my ASP.NET page? The code is exactly the same except for class type difference (Form / Page) and calling event handler (Form1_Load, Page_Load). Note: In the actual code, #DLL# and #RAWDATAFILE# are both absolute filenames to my DLL and raw data file respectively. Note: The DLL file was not created by Visual Studio. Form1.vb Public Class Form1 Declare Auto Function GetRawData Lib "#DLL#" (ByVal filename() As Byte, _ ByVal byteArray() As Byte, _ ByVal length As Int32) As Int32 Private Sub Form1_Load(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles MyBase.Load Dim buffer(10485760) As Byte Dim msg As String, length As Integer = 10485760 Dim filename As String = "#RAWDATAFILE#" length = GetRawData(Encoding.Default.GetBytes(filename), buffer, length) Default.aspx.vb Partial Public Class _Default Inherits System.Web.UI.Page Declare Auto Function GetRawData Lib "#DLL#" (ByVal filename() As Byte, _ ByVal byteArray() As Byte, _ ByVal length As Int32) As Int32 Protected Sub Page_Load(ByVal sender As Object, _ ByVal e As System.EventArgs) Handles Me.Load Dim buffer(10485760) As Byte Dim msg As String, length As Integer = 10485760 Dim filename As String = "#RAWDATAFILE#" length = GetRawData(Encoding.Default.GetBytes(filename), buffer, length)

    Read the article

< Previous Page | 763 764 765 766 767 768 769 770 771 772 773 774  | Next Page >