Search Results

Search found 5245 results on 210 pages for 'confused or too stupid'.

Page 191/210 | < Previous Page | 187 188 189 190 191 192 193 194 195 196 197 198  | Next Page >

• Why aren't Java's generics implicitly polymorphic?

  - by froadie

  I'm a bit confused about how Java generics handle inheritance / polymorphism. Assume the following hierarchy - Animal (Parent) Dog - Cat (Children) So suppose I have a method doSomething(List<Animal> animals). By all the rules of inheritance and polymorphism, I would assume that a List<Dog> is a List<Animal> and a List<Cat> is a List<Animal> - and so either one could be passed to this method. Not so. If I want to achieve this behavior, I have to explicitly tell the method to accept a list of any subset of Animal by saying doSomething(List<? extends Animal> animals). I understand that this is Java's behavior. My question is why? Why is polymorphism generally implicit, but when it comes to generics it must be specified?

  Read the article

• Processor, OS : 32bit, 64 bit

  - by Sandbox

  I am new to programming and come from a non-CS background (no formal degree). I mostly program winforms using C#. I am confused about 32 bit and 64 bit.... I mean, have heard about 32 bit OS, 32 bit processor and based on which a program can have maximum memory. How it affects the speed of a program. There are lot more questions which keep coming to mind. I tried to go through some Computer Organization and Architecture books. But, either I am too dumb to understand what is written in there or the writers assume that the reader has some CS background. Can someone explain me these things in a plain simple English or point me to something which does that. EDIT: I have read things like In 32-bit mode, they can access up to 4GB memory; in 64-bit mode, they can access much much more....I want to know WHY to all such things. BOUNTY: Answers below are really good....esp one by Martin. But, I am looking at a thorough explanation, but in plain simple English.

  Read the article

• Question about architecting asp.net mvc application ?

  - by Misnomer

  I have read little bit about architecture and also patterns in order to follow the best practices. So this is the architecture we have and I wanted to know what you think of it and any proposed changes or improvements to it - Presentation Layer - Contains all the views,controllers and any helper classes that the view requires also it containes the reference to Model Layer and Business Layer. Business Project - Contains all the business logic and validation and security helper classes that are being used by it. It contains a reference to DataAccess Layer and Model Layer. Data Access Layer - Contains the actual queries being made on the entity classes(CRUD) operations on the entity classes. It contains reference to Model Layer. Model Layer - Contains the entity framework model,DTOs,Enums.Does not really have a reference to any of the above layers. What are your thoughts on the above architecture ? The problem is that I am getting confused by reading about like say the repository pattern, domain driven design and other design patterns. The architecture we have although not that strict still is relatively alright I think and does not really muddle things but I maybe wrong. I would appreciate any help or suggestions here. Thanks !

  Read the article

• Where do you use Java code? Trouble sending .jar files

  - by leigero

  Apologies for the generic nature of this question. I have been learning Java for a few months now, and I've created a few simple projects which have some functionality. I wanted to send the projects to a friend and I'm running into countless errors and struggles. Passing a .jar file is causing "Main class not found" errors when they try to open it. I tried using third party software to wrap the .jar files into an .exe file and the same errors still persist. Beyond that, I'm convinced that passing around .jar files wrapped into .exe files via third party software is NOT how Java was intended to be used. I've read two books on Java and they all talk about structuring the language, but I'm confused about WHERE I'm supposed to be using this code because it has become painfully obvious that it is NOT intended to be passed around in file format. Is this a server programming language? Used on the back end of websites mainly? I'm not sure where one would be using the code written in Java.

  Read the article

• Is this the correct way to set up has many with multiple associations?

  - by user323763

  I'm trying to set up a new project for a music site. I'm learning ROR and am a bit confused about how to make join models/tables. Does this look right? I have users, playlists, songs, and comments. Users can have multiple playlists. Users can have multiple comments on their profile. Playlists can have multiple songs. Playlists can have comments. Songs can have comments. class CreateTables < ActiveRecord::Migration def self.up create_table :users do |t| t.string :login t.string :email t.string :firstname t.string :lastname t.timestamps end create_table :playlists do |t| t.string :title t.text :description t.timestamps end create_table :songs do |t| t.string :title t.string :artist t.string :album t.integer :duration t.string :image t.string :source t.timestamps end create_table :comments do |t| t.string :title t.text :body t.timestamps end create_table :users_playlists do |t| t.integer :user_id t.integer :playlist_id t.timestamps end create_table :playlists_songs do |t| t.integer :playlist_id t.integer :song_id t.integer :position t.timestamps end create_table :users_comments do |t| t.integer :user_id t.integer :comment_id t.timestamps end create_table :playlists_comments do |t| t.integer :playlist_id t.integer :comment_id t.timestamps end create_table :songs_comments do |t| t.integer :song_id t.integer :comment_id t.timestamps end end def self.down drop_table :playlists drop_table :comments drop_table :songs_comments drop_table :users_comments drop_table :users_playlists drop_table :users drop_table :playlists drop_table :songs drop_table :playlists end end

  Read the article

• Unable to retrieve data, mysql php pdo

  - by Kyle Hudson

  Hi, I have an issue, i cannot get any results from mysql on a production box but can on a development box, we use PHP 5.3 with MySQL (pdo). $sd = $this->dbh->quote($sd); $si_sql = "SELECT COUNT(*) FROM tbl_wl_data WHERE (site_domain = $sd OR siteDomainMasked = $sd);"; if($this->dbh->query($si_sql)->rowCount() > 0) { //gets to here, just doesnt get through the loop $sql = "SELECT pk_aid, site_name, site_css, site_img_sw, supportPhone FROM tbl_wl_data WHERE (site_domain = $sd OR siteDomainMasked = $sd);"; foreach($this->dbh->query($sql) as $wlsd) { //-- fails here if($wlsd['wl_status'] != '1') { require "_domainDisabled.php"; exit; } $this->pk_aid = $wlsd['pk_aid']; $this->siteTitle = $wlsd['site_name']; $this->siteCSS = $wlsd['site_css']; $this->siteImage = $wlsd['site_img_sw']; $this->siteSupportPhone = $wlsd['supportPhone']; } } else { throw new ERR_SITE_NOT_LINKED; } It just doesnt seem to get into the loopk, i ran the query in navicat and it returns the data. Really confused :S

  Read the article

• Load function in jquery

  - by user345579

  Hi, I am relatively new to jquery and would like to know why the below code wouldn't work. I am trying to access the content from a file residing on my site and not outside. Is it because I have the jquery lib loading from google and not my site? The error message that I get in IE browser is "Access Denied". I am confused why the access is denied if I am trying to load a file from the same server and even same folder. <html> <head> <script type="text/javascript" language="JavaScript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script> <script type="text/javascript" language="JavaScript"> $(document).ready(function(){ $("#response").load("http://www.mydomain.com/loadme.php?route=links/getlinks&path=2"); }); </script> </head> <body> <div id="response" style="border: 1px solid #000;height:500px;">&nbsp;</div> </body> </html> any one please help me. thanks

  Read the article

• How do I implement IEnumerable?

  - by Stacey

  I have a class that contains a static number of objects. This class needs to be frequently 'compared' to other classes that will be simple List objects. public partial class Sheet { public Item X{ get; set; } public Item Y{ get; set; } public Item Z{ get; set; } } the items are obviously not going to be "X" "Y" "Z", those are just generic names for example. The problem is that due to the nature of what needs to be done, a List won't work; even though everything in here is going to be of type Item. It is like a checklist of very specific things that has to be tested against in both code and runtime. This works all fine and well; it isn't my issue. My issue is iterating it. For instance I want to do the following... List<Item> UncheckedItems = // Repository Logic Here. UncheckedItems contains all available items; and the CheckedItems is the Sheet class instance. CheckedItems will contain items that were moved from Unchecked to Checked; however due to the nature of the storage system, items moved to Checked CANNOT be REMOVED from Unchecked. I simply want to iterate through "Checked" and remove anything from the list in Unchecked that is already in "Checked". So naturally, that would go like this with a normal list. foreach(Item item in Unchecked) { if( Checked.Contains(item) ) Unchecked.Remove( item ); } But since "Sheet" is not a 'List', I cannot do that. So I wanted to implement IEnumerable so that I could. Any suggestions? I've never implemented IEnumerable directly before and I'm pretty confused as to where to begin.

  Read the article

• How to implement the disposable pattern in a class that inherits from another disposable class?

  - by TheRHCP

  Hi, I often used the disposable pattern in simple classes that referenced small amount of resources, but I never had to implement this pattern on a class that inherits from another disposable class and I am starting to be a bit confused in how to free the whole resources. I start with a little sample code: public class Tracer : IDisposable { bool disposed; FileStream fileStream; public Tracer() { //Some fileStream initialization } public void Dispose() { this.Dispose(true); GC.SuppressFinalize(this); } protected virtual void Dispose(bool disposing) { if (!disposed) { if (disposing) { if (fileStream != null) { fileStream.Dispose(); } } disposed = true; } } } public class ServiceWrapper : Tracer { bool disposed; ServiceHost serviceHost; //Some properties public ServiceWrapper () { //Some serviceHost initialization } //protected override void Dispose(bool disposing) //{ // if (!disposed) // { // if (disposing) // { // if (serviceHost != null) // { // serviceHost.Close(); // } // } // disposed = true; // } //} } My real question is: how to implement the disposable pattern inside my ServiceWrapper class to be sure that when I will dispose an instance of it, it will dispose resources in both inherited and base class? Thanks.

  Read the article

• TCP/IP Implementation General Questions

  - by user2971023

  I've implemented the concepts shown here; http://wiki.unity3d.com/index.php/Simple_TCP/IP_Client_-_Server outside of unity and it works. (though i had to create the TCPIPServerApp from scratch as i could not find the base project anywhere). I have some general questions on how to use tcp/ip properly however. I've done some research on tcp/ip itself but I'm still a little confused. It seems like using the method above doesn't guarantee that I'll see the message (res). It just checks on every update to see if there is a different message in res. What if multiple messages are sent and the program lags or something, will i miss the earlier packet(s)? Should i instead do an array so it stores the last X messages? How do i know the data was received? Do I need to add a message id and build in my own ack into the data? Should i check to see if the port is in use before setting up a connection? Sorry for all the questions. This is all new to me but I enjoy this very much! ... Below already answered By Anton, Thanks It sounds like tcp uses its own packet numbering to ensure the packets end up in the right order on the other side. What if a packet is missed, are the subsequent packets thrown away? Or is this numbering and packet ordering, only for handling data that is broken out into multiple packets? TCP will automatically break the data into multiple packets if necessary right?

  Read the article

• when i set property(retain), one "self" = one "retain"?

  - by Walter

  although I'm about to finish my first app, I'm still confused about the very basic memory management..I've read through many posts here and apple document, but I'm still puzzled.. For example..I'm currently doing things like this to add a label programmatically: @property (retain, nonatomic) UILabel *showTime; @sythesize showTime; showTime = [[UILabel alloc] initWithFrame:CGRectMake(45, 4, 200, 36)]; [self.showTime setText:[NSString stringWithFormat:@"%d", time]]; [self.showTime setFont:[UIFont fontWithName:@"HelveticaRoundedLT-Bold" size:23]]; [self.showTime setTextColor:numColor]; self.showTime.backgroundColor = [UIColor clearColor]; [self addSubview:self.showTime]; [showTime release]; this is my current practice, for UILabel, UIButton, UIImageView, etc... [Alloc init] it without self., coz I know this will retain twice.. but after the allocation, I put back the "self." to set the attributes.. My gut feel tells me I am doing wrong, but it works superficially and I found no memory leak in analyze and instruments.. can anyone give my advice? when I use "self." to set text and set background color, does it retain one automatically? THX so much!

  Read the article

• Pointers to a typed variable in C#: Interfase, Generic, object or Class? (Boxing/Unboxing)

  - by PaulG

  First of all, I apologize if this has been asked a thousand times. I read my C# book, I googled it, but I can't seem to find the answer I am looking for, or I am missing the point big time. I am very confused with the whole boxing/unboxing issue. Say I have fields of different classes, all returning typed variables (e.g. 'double') and I would like to have a variable point to any of these fields. In plain old C I would do something like: double * newVar; newVar = &oldVar; newVar = &anotherVar; ... In C#, it seems I could do an interfase, but would require that all fields be properties and named the same. Breaks apart when one of the properties doesn't have the same name or is not a property. I could also create a generic class returning double, but seems a bit absurd to create a class to represent a 'double', when a 'double' class already exists. If I am not mistaken, it doesn't even need to be generic, could be a simple class returning double. I could create an object and box the typed variable to the newly created object, but then I would have to cast every time I use it. Of course, I always have the unsafe option... but afraid of getting to unknown memory space, divide by zero and bring an end to this world. None of these seem to be the same as the old simple 'double * variable'. Am I missing something here?

  Read the article

• (Java) Get value of string loaded into dynamic-type object?

  - by Michael

  I'm very new to Java (~10 days), so my code is probably pretty bad, but here's what I've got: ArgsDataHolder argsData = new ArgsDataHolder(); // a class that holds two // ArrayList's where each element // representing key/value args Class thisArgClass; String thisArgString; Object thisArg; for(int i=2; i< argsString.length; i++) { thisToken = argsString[i]; thisArgClassString = getClassStringFromToken(thisToken).toLowerCase(); System.out.println("thisArgClassString: " + thisArgClassString); thisArgClass = getClassFromClassString(thisArgClassString); // find closing tag; concatenate middle Integer j = new Integer(i+1); thisArgString = getArgValue(argsString, j, "</" + thisArgClassString + ">"); thisArg = thisArgClass.newInstance(); thisArg = thisArgClass.valueOf(thisArgString); argsData.append(thisArg, thisArgClass); } The user basically has to input a set of key/value arguments into the command prompt in this format: <class>value</class>, e.g. <int>62</int>. Using this example, thisArgClass would be equal to Integer.class, thisArgString would be a string that read "62", and thisArg would be an instance of Integer that is equal to 62. I tried thisArg.valueOf(thisArgString), but I guess valueOf(<String>) is only a method of certain subclasses of Object. For whatever reason, I can't seem to be able to cast thisArg to thisArgClass (like so: thisArg = (thisArgClass)thisArgClass.newInstance();, at which point valueOf(<String>) should become accessible. There's got to be a nice, clean way of doing this, but it is beyond my abilities at this point. How can I get the value of the string loaded into a dynamically-typed object (Integer, Long, Float, Double, String, Character, Boolean, etc.)? Or am I just overthinking this, and Java will do the conversion for me? :confused:

  Read the article

• Scheme Homework Assignment

  - by user1704677

  In a course I am taking we recently had to learn the programming language Scheme. I get all of the basics, which is pretty much all that we have gone though. I'm just having trouble learning to think in the different way that Scheme consists of. I was given an assignment and really do not even know how to start. I have sat here for a few hours trying to figure out how to even get started, but I'm kind of stumped. For the record, I'm not asking for the code to solve this problem, but more of some thoughts to get me on the right track. Anyway, here is the gist of the assignment... We are given a list of ten numbers that represent a voter's votes. The numbers are -1, 0 or 1. Then we are given a list of lists of Candidates, with a name and then ten numbers corresponding to that candidate's votes. These numbers are also -1 0 and 1. So for example. '(0 0 0 -1 -1 1 0 1 0 -1) '(Adams 0 1 -1 0 1 1 0 -1 -1 0 0) We are asked to implement a function called best_candidates that will take in a list of numbers (Voter) and a list of lists of Candidates. Then we have to compare the votes of the voter against the list of each candidate and return a list of names with the most common votes. So far, I've come up with a few things. I'm just confused on how I will check the values and retain the name of the voter? I guess I'm still stuck in thinking C/Java and it's making this very tough. Any suggestions to help get me started?

  Read the article

• An Array returned by a model association is not an Array?

  - by Warren

  We have a model association that looks something like this: class Example < ActiveRecord::Base has_many :others, :order => 'others.rank' end The rank column is an integer type. The details of these particular models are not really important though as we have found the same problem with other has_many associations between other models. We have also added to the Enumerable module: module Enumerable def method_missing(name) super unless name.to_s[0..7] == 'collect_' method = name.to_s[8..-1] collect{|element| element.send(method)} end end This adds a collect_id method that we can use to get an array of record ids from an array of ActiveRecord objects. So if we use a normal ActiveRecord find :all, we get a nice array which we can then use collect_id on but if we use Example.others.collect_id, we get NoMethodError: undefined method `collect_id' for #<Class:0x2aaaac0060a0> Example.others.class returns "Array" so is it lying or confused? Our solution thus far has been to use it this way: Example.others.to_a.collect_id This works but this seems a bit strange. Why would you have to do that? We are on Ruby 1.8.7 and Rails 2.3.4

  Read the article

• operator << : std::cout << i << (i << 1);

  - by Oops

  Hi, I use the stream operator << and the bit shifting operator << in one line. I am a bit confused, why does code A) not produce the same output than code B)? A) int i = 4; std::cout << i << " " << (i << 1) << std::endl; //4 8 B) myint m = 4; std::cout << m << " " << (m << 1) << std::endl; //8 8 class myint: class myint { int i; public: myint(int ii) { i = ii; } inline myint operator <<(int n){ i = i << n; return *this; } inline operator int(){ return i; } }; thanks in advance Oops

  Read the article

• HTML5 card game [closed]

  - by ChrisCa

  I created a card game in silverlight a year or so ago in order to learn a bit about Silverlight. I am now wanting to make a HTML5 version of the game in an effort to learn a little bit more about that. I am thinking I'd like to take advantage of stuff like Knockout.js and WebSockets and the canvas element. Now what I'm confused about is how to lay out the cards on the screen. With Silverlight I was able to make a "Hand" control, which was made up of two sub controls - the cards the player has in their hand and the ones they have on the table. And they in turn were made up of Card controls. Now I don't believe there is the concept on a User Control in javascript. So I am possibly thinking about this in entirely the wrong way. So my question is - how could I lay out some cards on the table and perhaps make reuse of something for each player? I have a client side JSON object called game, which contains an array of players. Each player has a hand which is made up of an array of in-hand cards and on-table cards. Ideally I would like to bind these to something using Knockout.js - but I don't know what I could bind to. Would I simply position images (of cards) on a canvas? Is there a way to make some kind of Hand object that each player could have and that I could bind to? Any advice? Or sample code you've seen elsewhere?

  Read the article

• error: 'void Base::output()' is protected within this context

  - by Bill

  I'm confused about the errors generated by the following code. In Derived::doStuff, I can access Base::output directly by calling it. Why can't I create a pointer to output() in the same context that I can call output()? (I thought protected / private governed whether you could use a name in a specific context, but apparently that is incomplete?) Is my fix of writing callback(this, &Derived::output); instead of callback(this, Base::output) the correct solution? #include <iostream> using std::cout; using std::endl; template <typename T, typename U> void callback(T obj, U func) { ((obj)->*(func))(); } class Base { protected: void output() { cout << "Base::output" << endl; } }; class Derived : public Base { public: void doStuff() { // call it directly: output(); Base::output(); // create a pointer to it: // void (Base::*basePointer)() = &Base::output; // error: 'void Base::output()' is protected within this context void (Derived::*derivedPointer)() = &Derived::output; // call a function passing the pointer: // callback(this, &Base::output); // error: 'void Base::output()' is protected within this context callback(this, &Derived::output); } }; int main() { Derived d; d.doStuff(); }

  Read the article

• Developing Modular Flex Applications

  - by ukdavo

  Hi there I'd like to be able to understand how to develop a Flex application such that I could provide implementation classes at runtime. In the Java world I'd specify interfaces in an JAR (e.g. myapp-api.jar), the implementation in a separate JAR (e.g. myapp-impl.jar) and package these along with other resources in the application WAR (e.g. myapp.war). Within the code of the application I would instantiate the implementation classes dynamically. Is this approach possible in Flex? I'm aware that I can instantiate classes dynamically so that's a good start. I'm a bit confused by modules, RSLs and SWCs though. I was hoping to create a SWF application that had references to an interfaces SWC and an implementation SWC. The idea is that if I need to tweak the application for a specific customer then I could create a new implementation SWC and not have to modify the SWF or interface SWC. Any ideas?

  Read the article

• .Net forms - intercepting the Close X event.

  - by Hamish Grubijan

  Hi, this must be a dumb question, but I cannot figure it out. I also cannot use the designer because coders before me managed to throw GUI and logic all in one, so now it is confused. I've got to do it the old school way. I have a Form which can be closed in 3 ways: Close button, File / Close menu, and the X icon. I want them all to do the same thing. Intercepting the button and the menu events is easy. In fact, both are hooked up to an onCloseConfig method. Btw, is there a better name for this method? private void onCloseConfig(object sender, System.EventArgs e) { if (! m_configControl.Modified) { Application.Exit(); // Or should it be this.Close(); } .... // Else present a dialog, ask if they want to save. } So, to intercept the X I tried: this.FormClosing +=new FormClosingEventHandler(this.onCloseConfig); I believe this is what causes an infinite loop. I do not want that :) FormClosed is another option, but it seems too late. I just want to intercept the fact that the X was clicked, not the fact that the form is closing. Please help. Thanks!

  Read the article

• Abstract Design Pattern implementation

  - by Pathachiever11

  I started learning design patterns a while ago (only covered facade and abstract so far, but am enjoying it). I'm looking to apply the Abstract pattern to a problem I have. The problem is: Supporting various Database systems using one abstract class and a set of methods and properties, which then the underlying concrete classes (inheriting from abstract class) would be implementing. I have created a DatabaseWrapper abstract class and have create SqlClientData and MSAccessData concrete class that inherit from the DatabaseWrapper. However, I'm still a bit confused about how the pattern goes as far as implementing these classes on the Client. Would I do the following?: DatabaseWrapper sqlClient = new SqlClientData(connectionString); This is what I saw in an example, but that is not what I'm looking for because I want to encapsulate the concrete classes; I only want the Client to use the abstract class. This is so I can support for more database systems in the future with minimal changes to the Client, and creating a new concrete class for the implementations. I'm still learning, so there might be a lot of things wrong here. Please tell me how I can encapsulate all the concrete classes, and if there is anything wrong with my approach. Many Thanks! PS: I'm very excited to get into software architecture, but still am a beginner, so take it easy on me. :)

  Read the article

• Memory interleaving

  - by Tim Green

  Hello, I have this question that has me rather confused. Suppose that a 1G x 32-bit main memory is built using 256M x 4-bit RAM chips and that this memory is byte-addressable. I have deduced that one would require 4*1G = 2^2*2*30 = 2^32 - so 32 bits to address the full memory. My problem now comes with, say, if you had memory (byte) address "14", determine which memory module this would go into. (There would have to be 8 chips per module to make the 32-bit wide memory, and 4 modules overall giving 32 chips in total. Modules are numbered from 0). In high-order interleave, it appears trivial that it's the first (0) memory module given a lot of the first few bits are 0. However, low-order interleave has me stumped. I can't figure out (for sure) how many bits are used to determine a memory module (possibly 2, given there are 4 in total?). The given solution is Module 3. This is not homework in the same sense so I will not be tagging it as such.

  Read the article

• Difference between the address space of parent process and its child process in Linux?

  - by abbas1707

  Hi, I am confused about it. I have read that when a child is created by a parent process, child gets a copy of its parent's address space. What it means here by copy? If i use code below, then it prints same addresses of variable 'a' which is on heap in all cases. i.e in case of child and parent. So what is happening here? #include <sys/types.h> #include <stdio.h> #include <unistd.h> #include <stdlib.h> int main () { pid_t pid; int *a = (int *)malloc(4); printf ("heap pointer %p\n", a); pid = fork(); if (pid < 0) { fprintf (stderr, "Fork Failed"); exit(-1); } else if (pid == 0) { printf ("Child\n"); printf ("in child heap pointer %p\n", a); } else { wait (NULL); printf ("Child Complete\n"); printf ("in parent heap pointer %p\n", a); exit(0); } }

  Read the article

• 'For' Loop Within a 'For' Loop and Then Another?

  - by BenjaminFranklin

  This has confused me quite a bit, but it's also really interesting! I want to loop through a grid of 9 elements in an array, multiply them all by 1/9. Then, I want to find the sum of those 9 elements and replace each individual element's with the value calculated as the sum. After I've done this, I want to move on to the next nine elements. To clarify, I want all 9 elements to be changed to myVal, in the code below. So far I've got the loop within a loop bit, but I don't know how to then go back and replace each of the values with the sum of all of them combined. Here's my code:- previousx = 0; previousy= 0; for (int x = previousx; x < previousx+4; x++) { for(int y = previousy; y < previousy+4; y++) { y = y*(1/9); yVal += y; } } Any advice would, of course, be greatly appreciated.

  Read the article

• Sending a message to nil?

  - by Ryan Delucchi

  As a Java developer who is reading Apple's Objective-C 2.0 documentation: I wonder as to what sending a message to nil means - let alone how it is actually useful. Taking an excerpt from the documentation: There are several patterns in Cocoa that take advantage of this fact. The value returned from a message to nil may also be valid: If the method returns an object, any pointer type, any integer scalar of size less than or equal to sizeof(void*), a float, a double, a long double, or a long long, then a message sent to nil returns 0. If the method returns a struct, as defined by the Mac OS X ABI Function Call Guide to be returned in registers, then a message sent to nil returns 0.0 for every field in the data structure. Other struct data types will not be filled with zeros. If the method returns anything other than the aforementioned value types the return value of a message sent to nil is undefined. Has Java rendered my brain incapable of grokking the explanation above? Or is there something that I am missing that would make this as clear as glass? Note: Yes, I do get the idea of messages/receivers in Objective-C, I am simply confused about a receiver that happens to be nil.

  Read the article

< Previous Page | 187 188 189 190 191 192 193 194 195 196 197 198  | Next Page >