Search Results

Search found 66233 results on 2650 pages for 'class method'.

Page 5/2650 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • C++: Create abstract class with abstract method and override the method in a subclass

    - by Martijn Courteaux
    Hi, How to create in C++ an abstract class with some abstract methods that I want to override in a subclass? How should the .h file look? Is there a .cpp, if so how should it look? In Java it would look like this: abstract class GameObject { public abstract void update(); public abstract void paint(Graphics g); } class Player extends GameObject { @Override public void update() { // ... } @Override public void paint(Graphics g) { // ... } } // In my game loop: for (int i = 0; i < objects.size(); i++) { objects.get(i).update(); } for (int i = 0; i < objects.size(); i++) { objects.get(i).paint(g); } Translating this code to C++ is enough for me.

    Read the article

  • Better solution then simple factory method when concrete implementations have different attributes

    - by danip
    abstract class Animal { function eat() {..} function sleep() {..} function isSmart() } class Dog extends Animal { public $blnCanBark; function isSmart() { return $this->blnCanBark; } } class Cat extends Animal { public $blnCanJumpHigh; function isSmart() { return $this->blnCanJumpHigh; } } .. and so on up to 10-20 animals. Now I created a factory using simple factory method and try to create instances like this: class AnimalFactory { public static function create($strName) { switch($strName) { case 'Dog': return new Dog(); case 'Cat': return new Cat(); default: break; } } } The problem is I can't set the specific attributes like blnCanBark, blnCanJumpHigh in an efficient way. I can send all of them as extra params to create but this will not scale to more then a few classes. Also I can't break the inheritance because a lot of the basic functionality is the same. Is there a better pattern to solve this?

    Read the article

  • Class or Dictionary

    - by user2038134
    I want to create a immutable Scale class in C#. public sealed class Scale { string _Name; string _Description; SomeOrderedCollection _ScaleValueDefinitions; Unit _Unit // properties .... // methods ContainsValue(double value) .... // constructors // all parameters except scalevaluedefinitions are optional // for a Scale to be useful atleast 1 ScaleValueDefinition should exist public Scale(string name, string description, SomeOrderedCollection scaleValueDefinitions, unit) { /* initialize */} } so first a ScaleValueDefinition should be represented by to values: Value (double) Definition (string) these values are known before the Scale class is created and should be unique. so what is the best approach. create a immutable class ScaleValueDefinition with value and definition as properties and use it in a list. use a dictionary. use another way i didn't think of... and how to implement it. for option 1. i can use params ScaleValueDefinition[] ValueDefinitions in the constructor, but how to do it for the other options? and as last at what amount of value's (properties) should i choose one option over the other?

    Read the article

  • C++ - Constructor or Initialize Method to Startup

    - by Bob Fincheimer
    I want to determine when to do non-trivial initialization of a class. I see two times to do initialization: constructor and other method. I want to figure out when to use each. Choice 1: Constructor does initialization MyClass::MyClass(Data const& data) : m_data() { // does non-trivial initialization here } MyClass::~MyClass() { // cleans up here } Choice 2: Defer initialization to an initialize method MyClass::MyClass() : m_data() {} MyClass::Initialize(Data const& data) { // does non-trivial initialization here } MyClass::~MyClass() { // cleans up here } So to try and remove any subjectivity I want to figure out which is better in a couple of situations: Class that encapsulates a resource (window/font/some sort of handle) Class that composites resources to do something (a control/domain object) Data structure classes (tree/list/etc.) [Anything else you can think of] Things to analyze: Performance Ease of use by other developers How error-prone/opportunities for bugs [Anything else you can think of]

    Read the article

  • PHP class data implementation

    - by Bakanyaka
    I'm studying OOP PHP and have watched two tutorials that implement user login\registration system as an example. But implementation varies. Which way will be more correct one to work with data such as this? Load all data retrieved from database as array into a property called something like _data on class creation and further methods operate with this property Create separate properties for each field retrieved from database, on class creation load all data fields into respective properties and operate with that properties separately? Then let's say I want to create a method that returns a list of all users with their data. Which way is better? Method that returns just an array of userdata like this: Array([0]=>array([id] => 1, [username] => 'John', ...), [1]=>array([id] => 2, [username] => 'Jack', ...), ...) Method that creates a new instance of it's class for each user and returns an array of objects

    Read the article

  • Access static class variable of parent class in Python

    - by fuenfundachtzig
    I have someting like this class A: __a = 0 def __init__(self): A.__a = A.__a + 1 def a(self): return A.__a class B(A): def __init__(self): # how can I access / modify A.__a here? A.__a = A.__a + 1 # does not work def a(self): return A.__a Can I access the __astatic variable in B? It's possible writing a instead of __a, is this the only way? (I guess the answer might be rather short: yes :)

    Read the article

  • Rails 3 Abstract Class vs Inherited Class

    - by R. Yanchuleff
    In my rails 3 model, I have two classes: Product, Service. I want both to be of type InventoryItem because I have another model called Store and Store has_many :InventoryItems This is what I'm trying to get to, but I'm not sure how to model this in my InventoryItem model and my Product and Service models. Should InventoryItem just be a parent class that Product and Service inherit from, or should InventoryItem be modeled as a class abstract of which Product and Service extend from. Thanks in advance for the advice!

    Read the article

  • Setting attributes of a class during construction from **kwargs

    - by Carson Myers
    Python noob here, Currently I'm working with SQLAlchemy, and I have this: from __init__ import Base from sqlalchemy.schema import Column, ForeignKey from sqlalchemy.types import Integer, String from sqlalchemy.orm import relationship class User(Base): __tablename__ = "users" id = Column(Integer, primary_key=True) username = Column(String, unique=True) email = Column(String) password = Column(String) salt = Column(String) openids = relationship("OpenID", backref="users") User.__table__.create(checkfirst=True) #snip definition of OpenID class def create(**kwargs): user = User() if "username" in kwargs.keys(): user.username = kwargs['username'] if "email" in kwargs.keys(): user.username = kwargs['email'] if "password" in kwargs.keys(): user.password = kwargs['password'] return user This is in /db/users.py, so it would be used like: from db import users new_user = users.create(username="Carson", password="1234") new_user.email = "[email protected]" users.add(new_user) #this function obviously not defined yet but the code in create() is a little stupid, and I'm wondering if there's a better way to do it that doesn't require an if ladder, and that will fail if any keys are added that aren't in the User object already. Like: for attribute in kwargs.keys(): if attribute in User: user.__attribute__[attribute] = kwargs[attribute] else: raise Exception("blah") that way I could put this in its own function (unless one hopefully already exists?) So I wouldn't have to do the if ladder again and again, and so I could change the table structure without modifying this code. Any suggestions?

    Read the article

  • base class , inheritate class sizeof()

    - by user1279988
    why sizeof(X) is 4 and sizeof(Y) is 8? and another question, in class X, only the int(i) count as sizeof() 4? member function does take any memory space? Plz tell me, thanks! class X { int i; public: X() { i = 0; } void set(int ii) { i = ii; } int read() const { return i; } int permute() { return i = i * 47; } }; class Y : public X { int i; // Different from X's i public: Y() { i = 0; } int change() { i = permute(); // Different name call return i; } void set(int ii) { i = ii; X::set(ii); // Same-name function call } }; cout << "sizeof(X) = " << sizeof(X) << endl; cout << "sizeof(Y) = "

    Read the article

  • Can Eclipse generate method-chaining setters

    - by Chris R
    I'd like to generate method-chaining setters (setters that return the object being set), like so: public MyObject setField (Object value) { this.field = value; return this; } This makes it easier to do one-liner instantiations, which I find easier to read: myMethod (new MyObject ().setField (someValue).setOtherField (someOtherValue)); Can Eclipse's templates be modified to do this? I've changed the content to include return this; but the signature is not changed.

    Read the article

  • Compare base class part of sub class instance to another base class instance

    - by Anders Abel
    I have number of DTO classes in a system. They are organized in an inheritance hierarchy. class Person { public int Id { get; set; } public string FirstName { get; set; } public string ListName { get; set; } } class PersonDetailed : Person { public string WorkPhone { get; set; } public string HomePhone { get; set; } public byte[] Image { get; set; } } The reason for splitting it up is to be able to get a list of people for e.g. search results, without having to drag the heavy image and phone numbers along. Then the full PersonDetail DTO is loaded when the details for one person is selected. The problem I have run into is comparing these when writing unit tests. Assume I have Person p1 = myService.GetAPerson(); PersonDetailed p2 = myService.GetAPersonDetailed(); // How do I compare the base class part of p2 to p1? Assert.AreEqual(p1, p2); The Assert above will fail, as p1 and p2 are different classes. Is it possible to somehow only compare the base class part of p2 to p1? Should I implement IEquatable<> on Person? Other suggestions?

    Read the article

  • Static method , Abstract method , Interface method comparision ?

    - by programmerist
    When i choose these methods? i can not decide which one i must prefer or when will i use one of them?which one give best performance? First Type Usage public abstract class _AccessorForSQL { public virtual bool Save(string sp, ListDictionary ld, CommandType cmdType); public virtual bool Update(); public virtual bool Delete(); public virtual DataSet Select(); } class GenAccessor : _AccessorForSQL { DataSet ds; DataTable dt; public override bool Save(string sp, ListDictionary ld, CommandType cmdType) { } public override bool Update() { return true; } public override bool Delete() { return true; } public override DataSet Select() { DataSet dst = new DataSet(); return dst; } Second Type Usage Also i can write it below codes: public class GenAccessor { public Static bool Save() { } public Static bool Update() { } public Static bool Delete() { } } Third Type Usage Also i can write it below codes: public interface IAccessorForSQL { bool Delete(); bool Save(string sp, ListDictionary ld, CommandType cmdType); DataSet Select(); bool Update(); } public class _AccessorForSQL : IAccessorForSQL { private DataSet ds; private DataTable dt; public virtual bool Save(string sp, ListDictionary ld, CommandType cmdType) { } } } I can use first one below usage: GenAccessor gen = New GenAccessor(); gen.Save(); I can use second one below usage: GenAccessor.Save(); Which one do you prefer? When will i use them? which time i need override method ? which time i need static method?

    Read the article

  • Ubuntu Screenshot Window Class

    - by Weylin Schreck
    I would like to know the class for the "thing" that pops up when you take a screen shot using the default screen capture utility in Ubuntu 12.04. When I do a full screen capture it lags a lot because of particular animation I use to open things like drop down menus. Therefore I’d like to disable that only. If someone could provide me with the window "class=" or however I would disable the animation there it would be greatly appreciated.

    Read the article

  • How do I set an array in one class with another array in another class

    - by Stef
    I've populated and array with data like this in one class... PowerClass.h NSMutableArray pickerArray; @property (nonatomic, retain) NSMutableArray pickerArray; - PowerClass.m @synthesize pickerArray; @implementation NSMutableArray *array = [[NSArray alloc] initWithObjects:@"stef", @"steve", @"baddamans", @"jonny", nil]; pickerArray = [NSMutableArray arrayWithArray:array]; And I'm trying to set the Array in another class WeekClass.h PowerClass *powerClass; NSMutableArray *pickerData; @property (nonatomic, retain) NSMutableArray pickerData; @property (nonatomic, retain) PowerClass *powerClass; WeekClass.m @implementation pickerData = [NSMutableArray arrayWithArray:powerClass.pickerArray]; I have no errors or warnings. It just crashes. The NSLog says that the powerClass.pickerArray is NULL. Please help point me in the right direction.

    Read the article

  • Global qualification in a class declarations class-head

    - by gf
    We found something similar to the following (don't ask ...): namespace N { struct A { struct B; }; } struct A { struct B; }; using namespace N; struct ::A::B {}; // <- point of interest Interestingly, this compiles fine with VS2005, icc 11.1 and Comeau (online), but fails with GCC: global qualification of class name is invalid before '{' token From C++03, Annex A, it seems to me like GCC is right: the class-head can consist of nested-name-specifier and identifier nested-name-specifier can't begin with a global qualification (::) obviously, neither can identifier ... or am i overlooking something?

    Read the article

  • Accessing Class Variables from a List in a nice way in Python

    - by Dennis
    Suppose I have a list X = [a, b, c] where a, b, c are instances of the same class C. Now, all these instances a,b,c, have a variable called v, a.v, b.v, c.v ... I simply want a list Y = [a.v, b.v, c.v] Is there a nice command to do this? The best way I can think of is: Y = [] for i in X Y.append(i.v) But it doesn't seem very elegant ~ since this needs to be repeated for any given "v" Any suggestions? I couldn't figure out a way to use "map" to do this.

    Read the article

  • Sending object C from class A to class B

    - by user278618
    Hi, I can't figure out how to design classes in my system. In classA I create object selenium (it simulates user actions at website). In this ClassA I create another objects like SearchScreen, Payment_Screen and Summary_Screen. # -*- coding: utf-8 -*- from selenium import selenium import unittest, time, re class OurSiteTestCases(unittest.TestCase): def setUp(self): self.verificationErrors = [] self.selenium = selenium("localhost", 5555, "*chrome", "http://www.someaddress.com/") time.sleep(5) self.selenium.start() def test_buy_coffee(self): sel = self.selenium sel.open('/') sel.window_maximize() search_screen=SearchScreen(self.selenium) search_screen.choose('lavazza') payment_screen=PaymentScreen(self.selenium) payment_screen.fill_test_data() summary_screen=SummaryScreen(selenium) summary_screen.accept() def tearDown(self): self.selenium.stop() self.assertEqual([], self.verificationErrors) if __name__ == "__main__": unittest.main() It's example SearchScreen module: class SearchScreen: def __init__(self,selenium): self.selenium=selenium def search(self): self.selenium.click('css=button.search') I want to know if there is anything ok with a design of those classes?

    Read the article

  • Class library modification / migration

    - by Clint
    I have 3 class libraries. A BBL, a DAL, and a DATA (about 15 datasets). Currently 4 [major] applications utilize the functionality in these DLL's. I'm rewriting one of those applications and I need to (1) Use some of the existing functionality in the libraries (2) Change some of it (3) Add new functionality (4) Add new datasets. I'm back and forth about the best way to do this, while keeping my risks at a minimum. Some thoughts.. 1) Use the existing projects and don't make any modifications, only additions 2) Make new libraries, bring over the code I can use, and make additions as needed 3) Implement partial classes in the existing projects Eventually all 4 applications will use the newest functionality, but it will be a slow migration; so the old code can't be depricated yet. Any thoughts?

    Read the article

  • Data classes: getters and setters or different method design

    - by Frog
    I've been trying to design an interface for a data class I'm writing. This class stores styles for characters, for example whether the character is bold, italic or underlined. But also the font-size and the font-family. So it has different types of member variables. The easiest way to implement this would be to add getters and setters for every member variable, but this just feels wrong to me. It feels way more logical (and more OOP) to call style.format(BOLD, true) instead of style.setBold(true). So to use logical methods insteads of getters/setters. But I am facing two problems while implementing these methods: I would need a big switch statement with all member variables, since you can't access a variable by the contents of a string in C++. Moreover, you can't overload by return type, which means you can't write one getter like style.getFormatting(BOLD) (I know there are some tricks to do this, but these don't allow for parameters, which I would obviously need). However, if I would implement getters and setters, there are also issues. I would have to duplicate quite some code because styles can also have a parent styles, which means the getters have to look not only at the member variables of this style, but also at the variables of the parent styles. Because I wasn't able to figure out how to do this, I decided to ask a question a couple of weeks ago. See Object Oriented Programming: getters/setters or logical names. But in that question I didn't stress it would be just a data object and that I'm not making a text rendering engine, which was the reason one of the people that answered suggested I ask another question while making that clear (because his solution, the decorator pattern, isn't suitable for my problem). So please note that I'm not creating my own text rendering engine, I just use these classes to store data. Because I still haven't been able to find a solution to this problem I'd like to ask this question again: how would you design a styles class like this? And why would you do that? Thanks on forehand!

    Read the article

  • designing solution to dynamically load class

    - by dot
    Background Information I have a web app that allows end users to connect to ssh-enabled devices and manipulate them. Right now, i only support one version of firmware. The logic is something like this: user clicks on a button to run some command on device. web application looks up the class name containing the correct ssh interface for the device, using the device's model name. (because the number of hardware models is so small, i have a list that's hardcoded in my web app) web app creates a new ssh object using the class loaded in step 2. ssh command is run and session closed. command results displayed on web page. This all works fine. Now the end user wants me to be able to support multiple versions of firmware. But the catch is, they don't want to have to document the firmware version anywhere becuase the amount of overhead this will create in maintaining the system database. In other words, I can't look up the firmware version based on the device. The good news is that it sounds like at most, I'll have to support two different versions of firmware per device. One option is to name the the classes like this: deviceX.1.php deviceX.2.php deviceY.1.php deviceY.2.php where "X" and "Y" represent the model names, and 1 and 2 represent the firmware versions. When a user runs a command, I will first try it with one of the class files, if it fails, i can try with the second. I think always try the newer version of firmware first... so let's say in the above example, I would load deviceX.2.php before deviceX.1.php. This will work, but it's not very efficient. But I can't think of another way around this. Any suggestions?

    Read the article

  • Override ActiveRecord#save, Method Alias? Trying to mixin functionality into save method...

    - by viatropos
    Here's the situation: I have a User model, and two modules for authentication: Oauth and Openid. Both of them override ActiveRecord#save, and have a fair share of implementation logic. Given that I can tell when the user is trying to login via Oauth vs. Openid, but that both of them have overridden save, how do "finally" override save such that I can conditionally call one of the modules' implementations of it? Here is the base structure of what I'm describing: module UsesOauth def self.included(base) base.class_eval do def save puts "Saving with Oauth!" end def save_with_oauth save end end end end module UsesOpenid def self.included(base) base.class_eval do def save puts "Saving with OpenID!" end def save_with_openid save end end end end module Sequencer def save if using_oauth? save_with_oauth elsif using_openid? save_with_openid else super end end end class User < ActiveRecord::Base include UsesOauth include UsesOpenid include Sequencer end I was thinking about using alias_method like so, but that got too complicated, because I might have 1 or 2 more similar modules. I also tried using those save_with_oauth methods (shown above), which almost works. The only thing that's missing is that I also need to call ActiveRecord::Base#save (the super method), so something like this: def save_with_oauth # do this and that super.save # the rest end But I'm not allowed to do that in ruby. Any ideas for a clever solution to this?

    Read the article

  • How to find rows between other rows w/ID then add class

    - by Ravex
    Hi guys. i'm stuck with my table. need create toggle rows function. but i no idea how to find sub rows in table. Some one can help me? I have table with many rows 500 All Rows have class="row-1,row-2.....row-600 etc" And all main rows also have class="parent" between each "parent" rows i have 6 rows So i need for toggle/collapse purposes find all (sub)rows betwen parent rows. and add class with id like in prevous parent row. For example: parent have class="row-1 parent" all sub must have - class="child-row-1" default table <table id="table"> <tr class="row-1 odd parent"> <th class="column-1">st. 3 - 5</th> <th class="column-2">Profile</th> <th class="column-3">Purpose</th> </tr> <tr class="row-2 even"> <td class="column-1">Metal Stamp</td> <td class="column-2">Width</td> <td class="column-3">Price</td> </tr> <tr class="row-3 odd"> <td class="column-1">Circle 3 - 5</td> <td class="column-2">28-110</td> <td class="column-3">21500</td> </tr> <tr class="row-4 even"> <td class="column-1">Circle 3 - 5</td> <td class="column-2">115-180</td> <td class="column-3">20700</td> </tr> <tr class="row-5 odd"> <td class="column-1">Cube 3 - 5</td> <td class="column-2">63-80</td> <td class="column-3">21500</td> </tr> <tr class="row-6 even"> <td class="column-1">Cube 3 - 5</td> <td class="column-2">100-220</td> <td class="column-3">20700</td> </tr> <tr class="row-7 odd"> <td class="column-1">Line 3 - 5</td> <td class="column-2">10-50 ? 40-200</td> <td class="column-3">27000</td> </tr> </table> in the end it should look like this: <table id="table"> <tr class="row-1 odd parent"> <th class="column-1">st. 3 - 5</th> <th class="column-2">Profile</th> <th class="column-3">Purpose</th> </tr> <tr class="row-2 even child-row-1"> <td class="column-1">Metal Stamp</td> <td class="column-2">Width</td> <td class="column-3">Price</td> </tr> <tr class="row-3 odd child-row-1"> <td class="column-1">Circle 3 - 5</td> <td class="column-2">28-110</td> <td class="column-3">21500</td> </tr> <tr class="row-4 even child-row-1"> <td class="column-1">Circle 3 - 5</td> <td class="column-2">115-180</td> <td class="column-3">20700</td> </tr> <tr class="row-5 odd child-row-1"> <td class="column-1">Cube 3 - 5</td> <td class="column-2">63-80</td> <td class="column-3">21500</td> </tr> <tr class="row-6 even child-row-1"> <td class="column-1">Cube 3 - 5</td> <td class="column-2">100-220</td> <td class="column-3">20700</td> </tr> <tr class="row-7 odd child-row-1"> <td class="column-1">Line 3 - 5</td> <td class="column-2">10-50 ? 40-200</td> <td class="column-3">27000</td> </tr> </table>

    Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >