Search Results

Search found 12953 results on 519 pages for 'abstract methods'.

Page 66/519 | < Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >

  • Ternary operators in C#

    - by pm_2
    With the ternary operator, it is possible to do something like the following (assuming Func1() and Func2() return an int: int x = (x == y) ? Func1() : Func2(); However, is there any way to do the same thing, without returning a value? For example, something like (assuming Func1() and Func2() return void): (x == y) ? Func1() : Func2(); I realise this could be accomplished using an if statement, I just wondered if there was a way to do it like this.

    Read the article

  • NoMethodError in UsersController#create

    - by Mike DeVerna
    I'm getting stuck on an error I'm getting when signing up a new user in Michael Hart's Ruby on Rails Tutorial. I'm new to rails but I've been searching for hours and can't seem to find anything to figure out the issue. My initial thought is that it's specific to the following line: redirect_to @user This is my file for users_controller.rb #!/bin/env ruby # encoding: utf-8 class UsersController < ApplicationController def show @user = User.find(params[:id]) end def new @user = User.new end def create @user = User.new(params[:user]) if @user.save flash[:success] = "Welcome to the Sample App!" ?????????????? redirect_to @user else render 'new' end end end This is the error message I get: NoMethodError in UsersController#create undefined method `??????????????' for # Rails.root: /Users/mikedeverna/Documents/rails_projects/sample_app Application Trace | Framework Trace | Full Trace app/controllers/users_controller.rb:18:in `create' Here is the code in my routes.rb file: SampleApp::Application.routes.draw do resources :users resources :sessions, only: [:new, :create, :destroy] root to: 'static_pages#home' match '/signup', to: 'users#new' match '/signin', to: 'sessions#new' match '/signout', to: 'sessions#destroy', via: :delete match '/help', to: 'static_pages#help' match '/about', to: 'static_pages#about' match '/contact', to: 'static_pages#contact'

    Read the article

  • How to identify each parameter type in a C# method?

    - by user465876
    I have a C# method say: MyMethod(int num, string name, Color color, MyComplexType complex) Using reflection, how can I distinctly identify each of the parameter types of any method? I want to perform some task by parameter type. If the type is simple int, string or boolean then I do something, if it is Color, XMLDocument, etc I do something else and if it is user defined type like MyComplexType or MyCalci etc then I want to do certain task. I am able to retrieve all the parameters of a method using ParameterInfo and can loop through each parameter and get their types. But how can I identify each data type? foreach (var parameter in parameters) { //identify primitive types?? //identify value types //identify reference types } Edit: this is apart of my code to create a propert grid sort of page where I want to show the parameter list with data types for the selected method. If the parameter has any userdefined type/reference type then I want to expand it further to show all the elements under it with datatypes.

    Read the article

  • php: avoiding __get in certain circumstances?

    - by user151841
    I have a class where I'm using __set. Because I don't want it to set just anything, I have an array of approved variables that it checks before it will actually set a class property. However, on construct, I want the __construct method to set several class properties, some of which are not in the approved list. So when construct happens, and I do $this->var = $value, I of course get my exception that I'm not allowed to set that variable. Can I get around this somehow?

    Read the article

  • C# return and display syntax issue

    - by thatdude
    I am having trouble passing the return value from TheMethod() to Main and displaying the word if the if statement is passed as true. I have thought of two ways of doing this, neither has worked but I think I am missing synatx. Using a return ?; non void method and then displaying the returned value. Using a void method and actually writing out(example below) So yes I am new at this, however I have made so many iterations everything is blending together and I have forgot what I have tried. Any help on the syntax be great for either of these ways. Basically I need it to iterate numbers 1,2,3,4 and depending on if the current iteration matches an expression in the if statements it will display a word. Example: if (3 = i) { Console.WriteLine("Word"); } Code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Proj5 { class Program { int i = 0; static void Main(int i) { for (i = 0; i < 101; i++) { Console.WriteLine("test"); } } string TheMethod(int i) { string f = "Word1"; string b = "Word2"; if (i == 3) { return f; } if (i == 5) { return b; } if (0 == (i % 3)) { return f; } if (0 == i % 5) { return b; } else { return b; } } } }

    Read the article

  • When To Use this.method()?

    - by Soo
    Hi SO, and happy Friday I have a question regarding the use of this.method();. My code seems to work without using the this., but I include it because it seems like the right thing to do. When should .this be used, and because it's presence doesn't always make a difference, what's the best practice for .this?

    Read the article

  • Why does this while terminate before receiving a value? (java)

    - by David
    Here's the relevant code snippet. public static Territory[] assignTerri (Territory[] board, String[] colors) { for (int i = 0; i<board.length; i++) { // so a problem is that Territory.translate is void fix this. System.out.print ("What team controls ") ; Territory.translate (i) ; System.out.println (" ?") ; boolean a = false ; while (a = false) { String s = getIns () ; if ((checkColor (s, colors))) { board[i].team = (returnIndex (s, colors)) ; a =true ; } else System.out.println ("error try again") ; } System.out.print ("How many unites are on ") ; Territory.translate (i) ; System.out.println (" ?") ; int n = getInt () ; board[i].population = n ; } return board ; } As an additional piece of information, checkColor just checks to make sure that its first argument, a string, is a string in one of the indexes of its second argument, an array. It seems to me that when the while the method gets a string from the keyboard and then only if that string checks out is a true and the while allowed to terminate. The output I get though is this: What team controls Alaska ? How many unites are on Alaska ? (there is space at the end to type in an input) This would seem to suggest that the while terminates before an input is ever typed in since the first line of text is within the while while the second line of text comes after it outside of it. Why is this happening?

    Read the article

  • Why does this while terminate before recieving a value? (java)

    - by David
    here's the relevant code snippet. public static Territory[] assignTerri (Territory[] board, String[] colors) { for (int i = 0; i<board.length; i++) { // so a problem is that Territory.translate is void fix this. System.out.print ("What team controls ") ; Territory.translate (i) ; System.out.println (" ?") ; boolean a = false ; while (a = false) { String s = getIns () ; if ((checkColor (s, colors))) { board[i].team = (returnIndex (s, colors)) ; a =true ; } else System.out.println ("error try again") ; } System.out.print ("How many unites are on ") ; Territory.translate (i) ; System.out.println (" ?") ; int n = getInt () ; board[i].population = n ; } return board ; } as an additional piece of information, checkColor just checks to make sure that its first argument, a string, is a string in one of the indexes of its second argument, an array. it seems to me that when the while the method gets a string from the keyboard and then only if that string checks out is a true and the while allowed to terminate. The output i get though is this: What team controls Alaska ? How many unites are on Alaska ? (there is space at the end to type in an input) This would seem to suggest that the while terminates before an input is ever typed in since the first line of text is within the while while the second line of text comes after it outside of it. why is this happening?

    Read the article

  • Targeting all subclassed CCSprites (cocos2d)

    - by Joethemonkey101
    I'm working on a method to end the level, but to do so, I have to see that all of the enemy character have been killed. If my enemies are CCSprites, how do I make a method that detects if all of them are dead? I'm tracking their health with an int called enemyHp. For example, this is an if statement I made to remove the enemy if (enemy.enemyHp <= 0) { To recap - I want to make a method that detects when all enemies have been killed. Thanks

    Read the article

  • what does "do" do here? (java)

    - by David
    I saw this bit of code on the interents somewhere. I'm wondering what thedo is for. public class LoopControl { public static void main(String[] args) { int count = 0; do { if(count % 2 == 0) { for(int j = 0; j < count; j++) { System.out.print(j+1); if(j < count-1) System.out.print(", "); } System.out.println(); } count++; } while(count <= 5); } }

    Read the article

  • High Sqlservr.exe Memory Usage

    - by user18576
    I have a problem with sqlservr.exe (version 2008). It use a more memory. I checked on windows taskbar manager, sqlservr.exe usage ( Mem usage - 8GB Ram). I dont know how can I fix it.Got the following metrics of the server using Perfmon: SQLServer:Buffer Manager Buffer cache hit ratio 13 SQLServer:Buffer Manager Page lookups/sec 46026128096 SQLServer:Buffer Manager Free pages 129295 SQLServer:Buffer Manager Total pages 997309 SQLServer:Buffer Manager Target pages 1053560 SQLServer:Buffer Manager Database pages 484117 SQLServer:Buffer Manager Reserved pages 0 SQLServer:Buffer Manager Stolen pages 383897 SQLServer:Buffer Manager Lazy writes/sec 384369 SQLServer:Buffer Manager Readahead pages/sec 69315446 SQLServer:Buffer Manager Page reads/sec 71280353 SQLServer:Buffer Manager Page writes/sec 12408371 SQLServer:Buffer Manager Checkpoint pages/sec 7053801 SQLServer:Buffer Manager Page life expectancy 735262 SQLServer:General Statistics Active Temp Tables 161 SQLServer:General Statistics Temp Tables Creation Rate 3131845 SQLServer:General Statistics Logins/sec 2336011 SQLServer:General Statistics Logouts/sec 2335984 SQLServer:General Statistics User Connections 27 SQLServer:General Statistics Transactions 0 SQLServer:Access Methods Full Scans/sec 34422821 SQLServer:Access Methods Range Scans/sec 2027247756 SQLServer:Access Methods Workfiles Created/sec 49771600 SQLServer:Access Methods Worktables Created/sec 28205828 SQLServer:Access Methods Index Searches/sec 4890715219 SQLServer:Access Methods FreeSpace Scans/sec 21178928 SQLServer:Access Methods FreeSpace Page Fetches/sec 21226653 SQLServer:Access Methods Pages Allocated/sec 41483279 SQLServer:Access Methods Extents Allocated/sec 4743504 SQLServer:Access Methods Extent Deallocations/sec 4806606 SQLServer:Access Methods Page Deallocations/sec 41419137 SQLServer:Access Methods Page Splits/sec 23834799 SQLServer:Memory Manager SQL Cache Memory (KB) 29160 SQLServer:Memory Manager Target Server Memory (KB) 8428480 SQLServer:Memory Manager Total Server Memory (KB) 7978472 Some body could help me please.And I really want to know the cause for the above.

    Read the article

  • How to have abstract and overriding constants in C# ?

    - by Chris
    Hi all, My code below won't compile. What am i doing wrong? I'm basically trying to have a public constant that is overridden in the base class. public abstract class MyBaseClass { public abstract const string bank = "???"; } public class SomeBankClass : MyBaseClass { public override const string bank = "Some Bank"; } Thanks as always for being so helpful!

    Read the article

  • How do I collect a bunch of Django abstract models in a QuerySet?

    - by Thierry Lam
    I have the following abstract Django models: class Food(models.Model): name = models.CharField(max_length=100) class Meta: abstract = True In one of my view, I created a bunch of Food model: panino = Food(name='Panino') poutine = Food(name='Poutine') food = [panino, poutine] From the above, I'm not saving the model and storing the Food model in a regular Python list. I want to store the above food models in a QuerySet object. How can I do that without storing any data to the database?

    Read the article

  • Which is a better practice - helper methods as instance or static?

    - by Ilian Pinzon
    This question is subjective but I was just curious how most programmers approach this. The sample below is in pseudo-C# but this should apply to Java, C++, and other OOP languages as well. Anyway, when writing helper methods in my classes, I tend to declare them as static and just pass the fields if the helper method needs them. For example, given the code below, I prefer to use Method Call #2. class Foo { Bar _bar; public void DoSomethingWithBar() { // Method Call #1. DoSomethingWithBarImpl(); // Method Call #2. DoSomethingWithBarImpl(_bar); } private void DoSomethingWithBarImpl() { _bar.DoSomething(); } private static void DoSomethingWithBarImpl(Bar bar) { bar.DoSomething(); } } My reason for doing this is that it makes it clear (to my eyes at least) that the helper method has a possible side-effect on other objects - even without reading its implementation. I find that I can quickly grok methods that use this practice and thus help me in debugging things. Which do you prefer to do in your own code and what are your reasons for doing so?

    Read the article

  • Overloading methods that do logically different things, does this break any major principles?

    - by siva.k
    This is something that's been bugging me for a bit now. In some cases you see code that is a series of overloads, but when you look at the actual implementation you realize they do logically different things. However writing them as overloads allows the caller to ignore this and get the same end result. But would it be more sound to name the methods more explicitly then to write them as overloads? public void LoadWords(string filePath) { var lines = File.ReadAllLines(filePath).ToList(); LoadWords(lines); } public void LoadWords(IEnumerable<string> words) { // loads words into a List<string> based on some filters } Would these methods better serve future developers to be named as LoadWordsFromFile() and LoadWordsFromEnumerable()? It seems unnecessary to me, but if that is better what programming principle would apply here? On the flip side it'd make it so you didn't need to read the signatures to see exactly how you can load the words, which as Uncle Bob says would be a double take. But in general is this type of overloading to be avoided then?

    Read the article

  • Interface (contract), Generics (universality), and extension methods (ease of use). Is it a right design?

    - by Saeed Neamati
    I'm trying to design a simple conversion framework based on these requirements: All developers should follow a predefined set of rules to convert from the source entity to the target entity Some overall policies should be able to be applied in a central place, without interference with developers' code Both the creation of converters and usage of converter classes should be easy To solve these problems in C# language, A thought came to my mind. I'm writing it here, though it doesn't compile at all. But let's assume that C# compiles this code: I'll create a generic interface called IConverter public interface IConverter<TSource, TTarget> where TSource : class, new() where TTarget : class, new() { TTarget Convert(TSource source); List<TTarget> Convert(List<TSource> sourceItems); } Developers would implement this interface to create converters. For example: public class PhoneToCommunicationChannelConverter : IConverter<Phone, CommunicationChannle> { public CommunicationChannel Convert(Phone phone) { // conversion logic } public List<CommunicationChannel> Convert(List<Phone> phones) { // conversion logic } } And to make the usage of this conversion class easier, imagine that we add static and this keywords to methods to turn them into Extension Methods, and use them this way: List<Phone> phones = GetPhones(); List<CommunicationChannel> channels = phones.Convert(); However, this doesn't even compile. With those requirements, I can think of some other designs, but they each lack an aspect. Either the implementation would become more difficult or chaotic and out of control, or the usage would become truly hard. Is this design right at all? What alternatives I might have to achieve those requirements?

    Read the article

  • Are super methods in JavaScript limited to functional inheritance, as per Crockford's book?

    - by kindohm
    In Douglas Crockford's "JavaScript: The Good Parts", he walks through three types of inheritance: classical, prototypal, and functional. In the part on functional inheritance he writes: "The functional pattern also gives us a way to deal with super methods." He then goes on to implement a method named "superior" on all Objects. However, in the way he uses the superior method, it just looks like he is copying the method on the super object for later use: // crockford's code: var coolcat = function(spec) { var that = cat(spec), super_get_name = that.superior('get_name'); that.get_name = function (n) { return 'like ' + super_get_name() + ' baby'; }; return that; }; The original get_name method is copied to super_get_name. I don't get what's so special about functional inheritance that makes this possible. Can't you do this with classical or prototypal inheritance? What's the difference between the code above and the code below: var CoolCat = function(name) { this.name = name; } CoolCat.prototype = new Cat(); CoolCat.prototype.super_get_name = CoolCat.prototype.get_name; CoolCat.prototype.get_name = function (n) { return 'like ' + this.super_get_name() + ' baby'; }; Doesn't this second example provide access to "super methods" too?

    Read the article

  • Is this JS code a good way for defining class with private methods?

    - by tigrou
    I was recently browsing a open source JavaScript project. The project is a straight port from another project in C language. It mostly use static methods, packed together in classes. Most classes are implemented using this pattern : Foo = (function () { var privateField = "bar"; var publicField = "bar";     function publicMethod() { console.log('this is public');     } function privateMethod() { console.log('this is private'); } return {   publicMethod : publicMethod, publicField : publicField }; })(); This was the first time I saw private methods implemented that way. I perfectly understand how it works, using a anonymous method. Here is my question : is this pattern a good practice ? What are the actual limitations or caveats ? Usually i declare my JavaScript classes like that : Foo = new function () { var privateField = "test"; this.publicField = "test";     this.publicMethod = function()     { console.log('this method is public'); privateMethod();     } function privateMethod() { console.log('this method is private'); } }; Other than syntax, is there any difference with the pattern show above ?

    Read the article

  • What is there so useful in the Decorator Pattern? My example doesn't work

    - by Green
    The book says: The decorator pattern can be used to extend (decorate) the functionality of a certain object I have a rabbit animal. And I want my rabbit to have, for example, reptile skin. Just want to decorate a common rabbit with reptile skin. I have the code. First I have abstract class Animal with everythig that is common to any animal: abstract class Animal { abstract public function setSleep($hours); abstract public function setEat($food); abstract public function getSkinType(); /* and more methods which for sure will be implemented in any concrete animal */ } I create class for my rabbit: class Rabbit extends Animal { private $rest; private $stomach; private $skinType = "hair"; public function setSleep($hours) { $this->rest = $hours; } public function setFood($food) { $this->stomach = $food; } public function getSkinType() { return $this->$skinType; } } Up to now everything is OK. Then I create abstract AnimalDecorator class which extends Animal: abstract class AnimalDecorator extends Animal { protected $animal; public function __construct(Animal $animal) { $this->animal = $animal; } } And here the problem comes. Pay attention that AnimalDecorator also gets all the abstract methods from the Animal class (in this example just two but in real can have many more). Then I create concrete ReptileSkinDecorator class which extends AnimalDecorator. It also has those the same two abstract methods from Animal: class ReptileSkinDecorator extends AnimalDecorator { public function getSkinColor() { $skin = $this->animal->getSkinType(); $skin = "reptile"; return $skin; } } And finaly I want to decorate my rabbit with reptile skin: $reptileSkinRabbit = ReptileSkinDecorator(new Rabbit()); But I can't do this because I have two abstract methods in ReptileSkinDecorator class. They are: abstract public function setSleep($hours); abstract public function setEat($food); So, instead of just re-decorating only skin I also have to re-decorate setSleep() and setEat(); methods. But I don't need to. In all the book examples there is always ONLY ONE abstract method in Animal class. And of course it works then. But here I just made very simple real life example and tried to use the Decorator pattern and it doesn't work without implementing those abstract methods in ReptileSkinDecorator class. It means that if I want to use my example I have to create a brand new rabbit and implement for it its own setSleep() and setEat() methods. OK, let it be. But then this brand new rabbit has the instance of commont Rabbit I passed to ReptileSkinDecorator: $reptileSkinRabbit = ReptileSkinDecorator(new Rabbit()); I have one common rabbit instance with its own methods in the reptileSkinRabbit instance which in its turn has its own reptileSkinRabbit methods. I have rabbit in rabbit. But I think I don't have to have such possibility. I don't understand the Decarator pattern right way. Kindly ask you to point on any mistakes in my example, in my understanding of this pattern. Thank you.

    Read the article

  • Pass a Delphi class to a C++ function/method that expects a class with __thiscall methods.

    - by Alan G.
    I have some MSVC++ compiled DLL's for which I have created COM-like (lite) interfaces (abstract Delphi classes). Some of those classes have methods that need pointers to objects. These C++ methods are declared with the __thiscall calling convention (which I cannot change), which is just like __stdcall, except a this pointer is passed on the ECX register. I create the class instance in Delphi, then pass it on to the C++ method. I can set breakpoints in Delphi and see it hitting the exposed __stdcall methods in my Delphi class, but soon I get a STATUS_STACK_BUFFER_OVERRUN and the app has to exit. Is it possible to emulate/deal with __thiscall on the Delphi side of things? If I pass an object instantiated by the C++ system then all is good, and that object's methods are called (as would be expected), but this is useless - I need to pass Delphi objects. Edit 2010-04-19 18:12 This is what happens in more detail: The first method called (setLabel) exits with no error (though its a stub method). The second method called (init), enters then dies when it attempts to read the vol parameter. C++ Side #define SHAPES_EXPORT __declspec(dllexport) // just to show the value class SHAPES_EXPORT CBox { public: virtual ~CBox() {} virtual void init(double volume) = 0; virtual void grow(double amount) = 0; virtual void shrink(double amount) = 0; virtual void setID(int ID = 0) = 0; virtual void setLabel(const char* text) = 0; }; Delphi Side IBox = class public procedure destroyBox; virtual; stdcall; abstract; procedure init(vol: Double); virtual; stdcall; abstract; procedure grow(amount: Double); virtual; stdcall; abstract; procedure shrink(amount: Double); virtual; stdcall; abstract; procedure setID(val: Integer); virtual; stdcall; abstract; procedure setLabel(text: PChar); virtual; stdcall; abstract; end; TMyBox = class(IBox) protected FVolume: Double; FID: Integer; FLabel: String; // public constructor Create; destructor Destroy; override; // BEGIN Virtual Method implementation procedure destroyBox; override; stdcall; // empty - Dont need/want C++ to manage my Delphi objects, just call their methods procedure init(vol: Double); override; stdcall; // FVolume := vol; procedure grow(amount: Double); override; stdcall; // Inc(FVolume, amount); procedure shrink(amount: Double); override; stdcall; // Dec(FVolume, amount); procedure setID(val: Integer); override; stdcall; // FID := val; procedure setLabel(text: PChar); override; stdcall; // Stub method; empty. // END Virtual Method implementation property Volume: Double read FVolume; property ID: Integer read FID; property Label: String read FLabel; end; I would have half expected using stdcall alone to work, but something is messing up, not sure what, perhaps something to do with the ECX register being used? Help would be greatly appreciated. Edit 2010-04-19 17:42 Could it be that the ECX register needs to be preserved on entry and restored once the function exits? Is the this pointer required by C++? I'm probably just reaching at the moment based on some intense Google searches. I found something related, but it seems to be dealing with the reverse of this issue.

    Read the article

  • can't query from dbpedia with a sparql

    - by austin powers
    I want to query from dbpedia using their sparql interface (http://dbpedia.org/sparql) I want to get the abstract of http://dbpedia.org/page/Herbie_Mann I know that I have to call abstract ontology http://dbpedia.org/ontology/abstract and my final sparsql query is like following : SELECT ?abstract WHERE { { <http://dbpedia.org/page/Herbie_Mann> <http://dbpedia.org/ontology/abstract> ?abstract} } but yet I'm not able to see anything. please help me as I am beginner in semantic web!

    Read the article

< Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >