Search Results

Search found 15423 results on 617 pages for 'uses clause'.

Page 525/617 | < Previous Page | 521 522 523 524 525 526 527 528 529 530 531 532  | Next Page >

• Should Service Depend on Many Repositories, or Break Them Up?

  - by Josh Pollard

  I'm using a repository pattern for my data access. So I basically have a repository per table/class. My UI currently uses service classes to actually get things done, and these service classes wrap, and therefore depend on repositories. In many cases my services are only dependent upon one or two repositories, so things aren't too crazy. Unfortunately, one of my forms in the UI expects the user to enter data that will span five different tables. For this form I made a single service class that depends upon five repositories. Then the methods within the service for saving and loading the data call the appropriate methods on all of the corresponding repositories. As you can imagine, the save and load methods in this service are really big. Also, unit testing this service is getting really difficult because I have to setup so many fake repositories. Would it have been a better choice to break this single service apart into a few smaller services? It would put more code at the UI layer, but would make the services smaller and more testable.

  Read the article

• What goes into the "Controller" in "MVC"?

  - by P72endragon

  I think I understand the basic concepts of MVC - the Model contains the data and behaviour of the application, the View is responsible for displaying it to the user and the Controller deals with user input. What I'm uncertain about is exactly what goes in the Controller. Lets say for example I have a fairly simple application (I'm specifically thinking Java, but I suppose the same principles apply elsewhere). I organise my code into 3 packages called app.model, app.view and app.controller. Within the app.model package, I have a few classes that reflect the actual behaviour of the application. These extends Observable and use setChanged() and notifyObservers() to trigger the views to update when appropriate. The app.view package has a class (or several classes for different types of display) that uses javax.swing components to handle the display. Some of these components need to feed back into the Model. If I understand correctly, the View shouldn't have anything to do with the feedback - that should be dealt with by the Controller. So what do I actually put in the Controller? Do I put the public void actionPerformed(ActionEvent e) in the View with just a call to a method in the Controller? If so, should any validation etc be done in the Controller? If so, how do I feedback error messages back to the View - should that go through the Model again, or should the Controller just send it straight back to View? If the validation is done in the View, what do I put in the Controller? Sorry for the long question, I just wanted to document my understanding of the process and hopefully someone can clarify this issue for me!

  Read the article

• Clarification on ZVals

  - by Beachhouse

  I was reading this: http://www.dereleased.com/2011/04/27/the-importance-of-zvals-and-circular-references/ And there's an example that lost me a bit. $foo = &$bar; $bar = &$foo; $baz = 'baz'; $foo = &$baz; var_dump($foo, $bar); /* string(3) "baz" NULL */ If you’ve been following along, this should make perfect sense. $foo is created, and pointed at a ZVal location identified by $bar; when $bar is created, it points at the same place $foo was pointed. That location, of course, is null. When $foo is reassigned, the only thing that changes is to which ZVal $foo points; if we had assigned a different value to $foo first, then $bar would still retain that value. I learned to program in C. I understand that PHP is different and it uses ZVals instead of memory locations as references. But when you run this code: $foo = &$bar; $bar = &$foo; It seems to me that there would be two ZVals. In C there would be two memory locations (and the values would be of the opposite memory location). Can someone explain?

  Read the article

• Update MySQl table onDrop?

  - by dougvt

  Hi all. I am writing a PHP/MySQL application (using CodeIgniter) that uses some jQuery functionality for dragging table rows. I have a table in which the user can drag rows to the desired order (kind of a queue for which I need to preserve the rank of each row). I've been trying to figure out how to (and whether I should) update the database each time the user drops a row, in order to simplify the UI and avoid a "Save" button. I have the jQuery working and can send a serialized list back to the server onDrop, but is it good design practice to run an update query this often? The table will usually have 30-40 rows max, but if the user drags row 1 far down the list, then potentially all the rows would need to be updated to update the rank field. I've been wondering whether to send a giant query to the server, to loop through the rows in PHP and update each row with its own Update query, to send a small serialized list to a stored procedure to let the server do all the work, or perhaps a better method I haven't considered. I've read that stored procedures in MySQL are not very efficient and use a separate process for each call. Any advice as to the right solution here? Thanks very much for your help!

  Read the article

• How can I use SCM on linked files in VS2008 projects?

  - by Tom Bushell

  Background: I'm using Visual-SVN V. 1.7.5 with VS2008. I'm fairly new to SVN. I have a Solution that uses source files that will be shared with other Solutions. I've put these files in a folder called "Shared", and added them to my Solution using "Add - Existing Item... - Add As Link" which works fine as far as VS2008 is concerned. But when I try to add the linked files to SVN using the "Add to Suversion" menu item on the file's context menu, I get a warning: "...not added to Subversion because it is out of working copy. Please setup working copy root using Visual SVN - Set Working Copy Root menu". I tried this, but this seems to change the root directory of the whole solution - not what I want to do. Googling and searching SO indicates that I may want to set up some SVN Externals. I tried to follow the examples, using the command line for the first time with Visual-SVN. But I just got a bunch of error messages I didn't understand. Questions: Are Externals the way to go here? If so, can someone provide some detailed, step-by-step help on how to do this with Visual-SVN?

  Read the article

• Dynamically adding custom view to RemoteViews

  - by Naidu

  Could any help me to do this?My code is like: public CustomClass extends View { //uses ondraw() to do something } For displaying my custom view on HomeScreen i created a class to extend Broadcast Receiver public class customAppWidgetProvider extends BroadcastReceiver { public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)) { RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.main); //Here i want to create my custom view class object and i want to add this view to linear layout in main.xml CustomClass object = new CustomClass(context) ; LinearLayout layout = new LinearLayout(context) ; layout.setLayoutParameters(new LayoutParameters(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT)); layout.addView(object); views.addview(R.id.linearlayout, (ViewGroup) layout) ; views.setOnClickPendingIntent(R.id.analog_appwidget, PendingIntent.getActivity(context, 0, new Intent(context, AlarmClock.class), PendingIntent.FLAG_CANCEL_CURRENT)); int[] appWidgetIds = intent.getIntArrayExtra( AppWidgetManager.EXTRA_APPWIDGET_IDS); AppWidgetManager gm = AppWidgetManager.getInstance(context); gm.updateAppWidget(appWidgetIds, views); } } } But adding viewgroup to RemoteView reference is not working... above main.xml contains only LinearLayout.I want to add custom view object to it.But after running this not showing anything on screen.. please help me to do this.Thanks in Advance.

  Read the article

• VB.Net Memory Issue

  - by Skulmuk

  We have an application that has some interesting memory usage issues. When it first opens, the program uses aroun 50-60MB of memory. This stays consistent on 32-bit machines. On 64-bit machines, however, re-activating the form in any way (clicking, dragging, alt-tabbing, etc.) adds around another 50MB to it's memory usage. It repeats this process several times before resetting back to around 45MB, at which point the cycle begins again. I've done some research and a lot of people have said that VB in general has pretty poor garbage collection, which could be affecting the software in some way. However, I've yet to find a solution. There are no events fired when the application is activated (as shown by 32-bit usage) - the applications is merely sitting awaiting the user's actions. At load, the system pulls some data into a tree view, but that's the only external connection, and it only re-fires the routine when the user makes a change to something and saves the change. Has anyone else experienced anything this strange, and if so, does anyone know of what might fix it? It seems strange that it only occurs under x64 systems. Thanks

  Read the article

• Why does LogonUser place user profiles in c:\users of the server?

  - by Lalit_M

  We have developed a ASP.NET web application and has implemented a custom authentication solution using active directory as the credentials store. Our front end application uses a normal login form to capture the user name and password and leverages the Win32 LogonUser method to authenticate the user’s credentials. When we are calling the LogonUser method, we are using the LOGON32_LOGON_NETWORK as the logon type. The issue we have found is that user profile folders are being created under the C:\Users folder of the web server. The folder seems to be created when a new user who has never logged on before is logging in for the first time. As the number of new users logging into the application grows, disk space is shrinking due to the large number of new user folders getting created. Has anyone seen this behavior with the Win32 LogonUser method? Does anyone know how to disable this behavior? I have tried LOGON32_LOGON_BATCH but it was giving an error 1385 in authentication user. I need either of the solution 1) Is there any way to stop the folder generation. 2) What parameter I need to pass this to work? Thanks

  Read the article

• How to implement a Linked List in Java?

  - by nbarraille

  Hello! I am trying to implement a simple HashTable in Java that uses a Linked List for collision resolution, which is pretty easy to do in C, but I don't know how to do it in Java, as you can't use pointers... First, I know that those structures are already implemented in Java, I'm not planning on using it, just training here... So I created an element, which is a string and a pointer to the next Element: public class Element{ private String s; private Element next; public Element(String s){ this.s = s; this.next = null; } public void setNext(Element e){ this.next = e; } public String getString(){ return this.s; } public Element getNext(){ return this.next; } @Override public String toString() { return "[" + s + "] => "; } } Of course, my HashTable has an array of Element to stock the data: public class CustomHashTable { private Element[] data; Here is my problem: For example I want to implement a method that adds an element AT THE END of the linked List (I know it would have been simpler and more efficient to insert the element at the beginning of the list, but again, this is only for training purposes). How do I do that without pointer? Here is my code (which could work if e was a pointer...): public void add(String s){ int index = hash(s) % data.length; System.out.println("Adding at index: " + index); Element e = this.data[index]; while(e != null){ e = e.getNext(); } e = new Element(s); } Thanks!

  Read the article

• WIN32 API question - Looking for answer asap

  - by Lalit_M

  We have developed a ASP.NET web application and has implemented a custom authentication solution using active directory as the credentials store. Our front end application uses a normal login form to capture the user name and password and leverages the Win32 LogonUser method to authenticate the user’s credentials. When we are calling the LogonUser method, we are using the LOGON32_LOGON_NETWORK as the logon type. The issue we have found is that user profile folders are being created under the C:\Users folder of the web server. The folder seems to be created when a new user who has never logged on before is logging in for the first time. As the number of new users logging into the application grows, disk space is shrinking due to the large number of new user folders getting created. Has anyone seen this behavior with the Win32 LogonUser method? Does anyone know how to disable this behavior? I have tried LOGON32_LOGON_BATCH but it was giving an error 1385 in authentication user. I need either of the solution 1) Is there any way to stop the folder generation. 2) What parameter I need to pass this to work? Thanks

  Read the article

• How to approach socket programming between C# -> Java (Android)

  - by Alex

  I've recently knocked up a server/client app for Windows & Android that allows one to send a file from Windows to an android phone over a socket connection. It works great for a single file but trying to send multiple files over in a single stream is causing me problems. I've also realised that aside from the binary data, I will need to send messages over the socket to indicate error states and other application messages. I have little experience with network programming and and wondering what is the best way forward. Basically the C# server side of the app just goes into a listening state and uses Socket.SendFile to transmit the file. On Android I use the standard Java Socket.getInputStream() to receive the file. That works great for a single file transfer, but how should I handle multiple files and error/messaging information? Do I need to use a different socket for each file? Should I be using a higher level framework to handle this or can I send everything over the single socket? Any other suggestions for frameworks or learning materials?

  Read the article

• Getting a `free()` error when deallocating with `delete` in the backtrace

  - by wonko

  I got the following error from gdb: *** glibc detected *** /.root0/autohome/u132/hsreekum/ipopt/ipopt/debug/Ipopt/examples/ex3/ex3: free(): invalid next size (fast): 0x0000000120052b60 *** Here's the backtrace: #0 0x000000555626b264 in raise () from /lib/libc.so.6 #1 0x000000555626cc6c in abort () from /lib/libc.so.6 #2 0x00000055562a7b9c in __libc_message () from /lib/libc.so.6 #3 0x00000055562aeabc in malloc_printerr () from /lib/libc.so.6 #4 0x00000055562b036c in free () from /lib/libc.so.6 #5 0x000000555561ddd0 in Ipopt::TNLPAdapter::~TNLPAdapter () from /home/ba01/u132/hsreekum/ipopt/ipopt/build/lib/libipopt.so.1 #6 0x00000055556a9910 in Ipopt::GradientScaling::~GradientScaling () from /home/ba01/u132/hsreekum/ipopt/ipopt/build/lib/libipopt.so.1 #7 0x00000055557241b8 in Ipopt::OrigIpoptNLP::~OrigIpoptNLP () from /home/ba01/u132/hsreekum/ipopt/ipopt/build/lib/libipopt.so.1 #8 0x00000055556ae7f0 in Ipopt::IpoptAlgorithm::~IpoptAlgorithm () from /home/ba01/u132/hsreekum/ipopt/ipopt/build/lib/libipopt.so.1 #9 0x0000005555602278 in Ipopt::IpoptApplication::~IpoptApplication () from /home/ba01/u132/hsreekum/ipopt/ipopt/build/lib/libipopt.so.1 #10 0x0000005555614428 in FreeIpoptProblem () from /home/ba01/u132/hsreekum/ipopt/ipopt/build/lib/libipopt.so.1 #11 0x0000000120001610 in main () at ex3.c:169` And here's the code for Ipopt::TNLPAdapter::~TNLPAdapter () TNLPAdapter::~TNLPAdapter() { delete [] full_x_; delete [] full_lambda_; delete [] full_g_; delete [] jac_g_; delete [] c_rhs_; delete [] jac_idx_map_; delete [] h_idx_map_; delete [] x_fixed_map_; delete [] findiff_jac_ia_; delete [] findiff_jac_ja_; delete [] findiff_jac_postriplet_; delete [] findiff_x_l_; delete [] findiff_x_u_; } My question is : why does free() throw an error when ~TNLPAdapter() uses delete[]? Also, I would like to step through ~TNLPAdapter() so I can see which deallocation causes the error. I believe the error occurs in the external library (IPOPT) but I have compiled it with debug flags on ; is this sufficient?

  Read the article

• Rails using plural table names even though I told it to use singular

  - by Jason Swett

  I tried to run rake test:profile and I got this error: ... Table 'mcif2.accounts' doesn't exist: DELETE FROM `accounts` I know accounts doesn't exist. It's called account. I know Rails uses plural table names by default but here's what my config/environment.rb looks like: # Load the rails application require File.expand_path('../application', __FILE__) # Initialize the rails application McifRails::Application.initialize! ActiveRecord::Base.pluralize_table_names = false And here's what db/schema.rb looks like: ActiveRecord::Schema.define(:version => 0) do create_table "account", :force => true do |t| t.integer "customer_id", :limit => 8, :null => false t.string "account_number", :null => false t.integer "account_type_id", :limit => 8 t.date "open_date", :null => false So I don't understand why Rails still wants to call it accounts sometimes. Any ideas? If it helps give any clues at all, here are the results of grep -ir 'accounts' *.

  Read the article

• How do I use has_many :through and in_place_edit?

  - by Angela

  I have two Models: Campaign and Contact. A Campaign has_many Contacts. A Contact has_many Campaigns. Currently, each Contact has a contact.date_entered attribute. A Campaign uses that date as the ate to count down to the different Events that belong_to the Campaign. However, there are situations where a Campaign for a specific Contact may need to be delayed by X number of days. In this instance, the campaigncontact.delaydays = 10. In some cases, the Campaign must be stopped altogether for the specific Contact, so for now I set campaigncontact.delaydays = 1. (Are there major problems with that?) By default, I am assuming that no campaigncontact exists (but not sure how that works?) So here's what I've tried to do: class Contact < ActiveRecord::Base has_many :campaigncontacts has_many :campaigns, :through => :campaigncontacts end class Campaign < ActiveRecord::Base has_many :campaigncontacts has_many :contacts, :through => :campaigncontacts end script/generate model campaigncontact campaign_id:integer contact_id:integer delaydays:integer class Campaigncontact < ActiveRecord::Base belongs_to :campaign belongs_to :contact end So, here's the question: Is the above correct? If so, how do I allow a user to edit the delay of a campaign for a specific Contact. For now, I want to do so from the Contact View. This is what I tried: In the Contact controller (?) in_place_edit_for :campaigncontact, column.delaydays And in the View <%= in_place_editor_field :campaigncontact, :delaydays %> How can I get it right?

  Read the article

• JavaScript Fails to load content correctly on start

  - by Gaz_Edge

  I have inherited an image gallery constructed using javascript. I believe it uses a variation of JQuery, but it seems to have been heavily edited. The gallery loads the first image on page load. Each image has comments below them. There are forward and backward arrows that move between images. The problem I seem to have is that if there is a comment on image one, it is not loaded on page start, the only way to get it to display is to click forward to the next image, then click back to image one. The comment is then shown. All the comments are loaded into a script in the header under var sent_comments = [{COMMENTS}] The comment HTML code on loading is as follows; <div id="comments_container"> <div id="comments"> </div> </div> Once I have clicked to image two and then back to image one, the code is; <div id="comments_container"> <div id="comments"> SOME COMMENT </div> </div> Previous image button is: <a class="prev save_state" href="#"> <img src="/next.png?" alt="Next"> </a> Im new to javascript so not really sure what I will need to do to ensure the comment is loaded for the first image when the page loads. Code here: http://static.albumexposure.net/assets/presentation-9f47b054d96f9ec2459e89619a5fe9b4.js http://static.albumexposure.net/assets/presentations/book-699d82a2beb39df264e54c5d2578e0e4.js

  Read the article

• Template specialization to use default type if class member typedef does not exist

  - by Frank

  Hi Everyone, I'm trying to write code that uses a member typedef of a template argument, but want to supply a default type if the template argument does not have that typedef. A simplified example I've tried is this: struct DefaultType { DefaultType() { printf("Default "); } }; struct NonDefaultType { NonDefaultType() { printf("NonDefault "); } }; struct A {}; struct B { typedef NonDefaultType Type; }; template<typename T, typename Enable = void> struct Get_Type { typedef DefaultType Type; }; template<typename T> struct Get_Type< T, typename T::Type > { typedef typename T::Type Type; }; int main() { Get_Type::Type test1; Get_Type::Type test2; } I would expect this to print "Default NonDefault", but instead it prints "Default Default". My expectation is that the second line in main() should match the specialized version of Get_Type, because B::Type exists. However, this does not happen. Can anyone explain what's going on here and how to fix it, or another way to accomplish the same goal? Thank you.

  Read the article

• Footprint of Lua on a PPC Micro

  - by Adam Shiemke

  We're developing some code on Freescale PPC micros (5517 and 5668 at the moment), and I was wondering if we could put Lua on them. The devices need to be easily programmed/reconfigured in the field, and the current product uses a proprietary interpreted logic language that can be loaded in, and our software (written in C) runs an interpreter. I would like to move to a better language (the implementation is a bit buggy and slow), so I'm considering Lua, but the memory footprint must be very low. For the 5517 (which we may not use), the maximum RAM is 80K. Things are better on the 5668, with 592K of RAM. So does anyone know if I can put Lua on bare metal? We're effectively not running an OS. If so, are there any estimates on what kind of memory footprint we might see? How much effort it would take? Failing this, does anyone know of any kind of interpreter that might be better in a memory-constrained environment without an OS? Or are we better just rolling our own?

  Read the article

• Why do I get 'Connection refused - connect(2)' for some models?

  - by Will

  I have a rails application running for the past 90 days that suddenly stopped working. Debugging the problem I found that I can read from the DB but not write to it. At least for certain models. There is one model that I can save whereas all others return Connection refused - connect(2) when I attempt to save them. They all used to work fine last month. I have no idea how to determine what the problem may be. Unfortunately I do not have access to the actual server remotely right now so I am limited in my debugging ability. I was able to get some non-tech people to run simple commands though that may help identify my problem. I will also be getting access tomorrow at some point. 1 Check from the console ./script/console >> a = Post.last.clone => #<Post id: nil, title: "test"... >> a.ex_id = 7 >> a.save Connection refused - connect(2) ... ... >> b = Story.last.console => #<Story id: nil, title: "test"... >> a.ex_id = 7 >> a.save => true I am not sure why this works for story and not post. This is consistent over many tests. 2 Check from mysql ./script/dbconsole -p mysql> INSERT INTO Posts (`title`,`body`, `ex_id`) SELECT `title`, `body`, 7 FROM Posts WHERE ID = 1; Query OK, 1 row affected (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0 And as you can see I am able to write to the table with the same credientials that Rails uses? Does anyone know why I get connection refused in the console?

  Read the article

• Voice Recognition Google API

  - by user2966744

  thanks for reading. I'm creating a simple web based drawing app that uses speech recognition. I have created a simple page, the project is on github here: https://github.com/a5hton/speechdraw It has a 16x16 pixel grid. I would like to be able to draw on this grid by using simple words. For example if you say "right", the pixel to the right will be colored black. If you say "down" the pixel below the last one will be colored black. You can say up, down, left or right and the corresponding pixels will be colored. Saying "erase" will switch to erase mode, colouring the pixels back to their original color. Saying "lift" will lift the pen off the page. Saying "draw" will enable the draw mode. Could you please help me work out how to make this happen. Please see the simple page at to get an understanding. Thank you! Cheers, Michael

  Read the article

• Android - How to decide wether to run a Service in a separate Process?

  - by pableu

  I am working on an Android application that collects sensor data over the course of multiple hours. For that, we have a Service that collects the Sensor Data (e.g. Acceleration, GPS, ..), does some processing and stores them remotely on a server. Currently, this Service runs in a separate process (using android:service=":background" in the manifest). This complicates the communication between the Activities and the Service, but my predecessors created the Application this way because they thought that separating the Service from the Activities would make it more stable. I would like some more factual reasons for the effort of running a separate process. What are the advantages? Does it really run more stable? Is the Service less likely to be killed by the OS (to free up resources) if it's in a separate process? Our Application uses startForeground() and friends to minimize the chance of getting killed by the OS. The Android docs are not very specific about this, the mostly state that it depends on the Application's purpose ;-) TL;DR What are objective reasons to put a long-running Service in a separate process (in Android)?

  Read the article

• How can I combine a LINQ query with an IQueryable<Guid>

  - by John

  I have a LINQ query that uses 1 table + a large number of views. I'd like to be able to write something like this: IQueryable<Guid> mostViewedWriters; switch (datePicker) { case DatePicker.Last12Hours: mostViewedWriters = from x in context.tempMostViewed12Hours select x.GuidId; break; case DatePicker.Last24Hours: mostViewedWriters = from x in context.tempMostViewed12Hours select x.GuidId; break; case DatePicker.Last36Hours: mostViewedWriters = from x in context.tempMostViewed12Hours select x.GuidId; break; } var query = from x1 in context.Articles join x2 in context.Authors on x1.AuthorId == x2.AuthorId join x3 in mostViewedWriters on x2.AuthorId == x3.Id select new { x2.AuthorName, x1.ArticleId, x1.ArticleTitle }; The above C# is pseudo-code written to protect the innocent (me). The gist of the question is this: I have a query that is related to the results of a view. That view, however, could be one of many different views. All the views return the same data type. I thought that I might be able to create an IQueryable that would contain the Ids that I need and use that query. Alas, that effort has stalled.

  Read the article

• CakePHP: Missing database table

  - by Justin

  I have a CakePHP application that is running fine locally. I uploaded it to a production server and the first page that uses a database connection gives the "Missing Database Table" error. When I look at the controller dump, it's complaining about the first table. I've tried a variety of things to fix this problem, with no luck: I've confirmed that at the command line I can login with the given MySQL credentials in database.php I've confirmed this table exists I've tried using the MySQL root credentials (temporarily) to see if the problem lies with permissions of the user. The same error appeared. My debug level is currently set to 3 I've deleted the entire contents of /app/tmp/cache I've set 777 permissions on /app/tmp* I've confirmed that I can run DESCRIBE commands at the commant line MySQL when logged in with the MySQL credentials used by by the application I've verified that the CakePHP log file only contains the error I'm setting in the browser window. I've tried all the suggestions I could find in similar postings on SO I've Googled around and didn't find any other ideas I think I've eliminating the obvious problems and my research isn't turning anything up. I feel like I'm missing something obvious. Any ideas?

  Read the article

• C++0x Smart Pointer Comparisons: Inconsistent, what's the rationale?

  - by GManNickG

  In C++0x (n3126), smart pointers can be compared, both relationally and for equality. However, the way this is done seems inconsistent to me. For example, shared_ptr defines operator< be equivalent to: template <typename T, typename U> bool operator<(const shared_ptr<T>& a, const shared_ptr<T>& b) { return std::less<void*>()(a.get(), b.get()); } Using std::less provides total ordering with respect to pointer values, unlike a vanilla relational pointer comparison, which is unspecified. However, unique_ptr defines the same operator as: template <typename T1, typename D1, typename T2, typename D2> bool operator<(const unique_ptr<T1, D1>& a, const unique_ptr<T2, D2>& b) { return a.get() < b.get(); } It also defined the other relational operators in similar fashion. Why the change in method and "completeness"? That is, why does shared_ptr use std::less while unique_ptr uses the built-in operator<? And why doesn't shared_ptr also provide the other relational operators, like unique_ptr? I can understand the rationale behind either choice: with respect to method: it represents a pointer so just use the built-in pointer operators, versus it needs to be usable within an associative container so provide total ordering (like a vanilla pointer would get with the default std::less predicate template argument) with respect to completeness: it represents a pointer so provide all the same comparisons as a pointer, versus it is a class type and only needs to be less-than comparable to be used in an associative container, so only provide that requirement But I don't see why the choice changes depending on the smart pointer type. What am I missing? Bonus/related: std::shared_ptr seems to have followed from boost::shared_ptr, and the latter omits the other relational operators "by design" (and so std::shared_ptr does too). Why is this?

  Read the article

• Why is the operation address incremented by two?

  - by Gavin Jones

  I am looking at a Javascript emulator of a NES to try and understand how it works. On this line: addr = this.load(opaddr+2); The opcode is incremented by two. However, the documentation (see appendix E) I'm reading says: Zero page addressing uses a single operand which serves as a pointer to an address in zero page ($0000-$00FF) where the data to be operated on can be found. By using zero page addressing, only one byte is needed for the operand, so the instruction is shorter and, therefore, faster to execute than with addressing modes which take two operands. An example of a zero page instruction is AND $12. So if the operand's argument is only one byte, shouldn't it appear directly after it, and be + 1 instead of + 2? Why +2? This is how I think it works, which may be incorrect. Suppose our memory looks like: ------------------------- | 0 | 1 | 2 | 3 | 4 | 5 | <- index ------------------------- | a | b | c | d | e | f | <- memory ------------------------- ^ \ PC and our PC is 0, pointing to a. For this cycle, we say that the opcode: var pc= 0; //for example's sake var opcode= memory[pc]; //a So shouldn't the first operand be the next slot, i.e. b? var first_operand = memory[pc + 1]; //b

  Read the article

• How to determine which element(s) are visible in an overflowed <div>

  - by jjross

  Basically, I'm trying to implement a system that behaves similar to the reading pane that's built into the Google Reader interface. If you haven't seen it, Google Reader presents each article in a separate box and as you scroll it highlights the current box (and marks the article as read). In addition to this, you can move forward or backward in the article list by clicking the previous and next buttons in the UI. I've basically figured out how to do most of the functionality. However, I'm not sure how I can determine which of my divs is currently visible in in the scrollable pane. I have a div that is set to overflow:auto. Inside of this div, there are other divs, each one containing a piece of content. I've used the following jquery plugin to make everything scroll based on a click of the "next" or "previous" button and it works like a charm: http://demos.flesler.com/jquery/serialScroll/ But I can't tell which div has "focus" in the scrollable pane. I'd like to be able to do this for two reasons. I'd like to highlight the item that the user is currently reading (similar to Google Reader). I need to do this regardless of whether or not they used the plugin to get there or used the browser's scroll bar. I need to be able to tell the plugin which item has focus so that my call to scroll to the "next" pane actually uses the currently viewed pane (and not just the previous pane that the plugin scrolled from). I've tried doing some searching but I can't seem to figure out a way to do this. I found lots of ways to scroll to a particular item, but I can't find a way to determine which element is visible in an overflowed div. If I can determine which items are visible, I can (probably) figure out the rest. I'm using jquery if that helps. Thanks!

  Read the article

< Previous Page | 521 522 523 524 525 526 527 528 529 530 531 532  | Next Page >