Search Results

Search found 10556 results on 423 pages for 'practical approach'.

Page 280/423 | < Previous Page | 276 277 278 279 280 281 282 283 284 285 286 287  | Next Page >

• Store form values for later submission

  - by kim griggs

  I have a Rails app that lets users create tutorials and quizzes. There are many users taking the quizzes and many quizzes in a tutorial. My client wants the quiz results to persist when a student navigates away from the quiz. So the use case would be: User starts to take quiz User answers some of the questions User navigates away from quiz to check a fact in the tutorial User goes back to quiz and their answers are still there User finishes quiz and submits Now this would be pretty easy to do if I enforced a "Save" submit so that the answers could be stored in a session or whatever, but the client (and I agree) thinks people will not remember to save before navigating away. Looking for advice on how to approach this. I'm thinking an observer and cookies.

  Read the article

• C: using clock() to measure time in multi-threaded programs

  - by Shinka

  I've always used clock() to measure how much time my application took from start to finish, as; int main(int argc, char *argv[]) { const clock_t START = clock(); // ... const double T_ELAPSED = (double)(clock() - START) / CLOCKS_PER_SEC; } Since I've started using POSIX threads this seem to fail. It looks like clock() increases N times faster with N threads. As I don't know how many threads are going to be running simultaneously, this approach fails. So how can I measure how much time has passed ?

  Read the article

• Is memcached a dinosaur in comparison to Redis?

  - by Industrial

  Hi everyone, I have worked quite a bit with memcached the last weeks and just found out about Redis. When I read this part of their readme, I suddenly got a warm, cozy feeling in my stomach: Redis can be used as a memcached on steroids because is as fast as memcached but with a number of features more. Like memcached, Redis also supports setting timeouts to keys so that this key will be automatically removed when a given amount of time passes. This sounds amazing. I'd also found this page with benchmarks: http://www.ruturaj.net/redis-memcached-tokyo-tyrant-mysql-comparison So, honestly - Is memcache really that old dinousaur that is a bad choice from a performance perspective when compared to this newcomer called Redis? I haven't heard lot about Redis previously, thereby the approach for my question!

  Read the article

• SQLITE (C/C++interface) - How to commit a transaction

  - by AJ

  I am using sqlite c/c++ interface. Now here is my scenario - I have 3 tables (related tables) say A, B, C. Now, there is a function called Set, which get some inputs and based on the inputs inserts rows into these three tables. (sometimes it can be an update in one of the tables) Now I need two things. One, i dont want autocommit feature. Basically I would like to commit after every 1000 calls to Set function Secondly, within the set function itself, if i find that after inserting into two tables, the third insert fails, then i have to revert, those particular changes in that Set function call. Now i dont see any sqlite3_commit function exposed. I only see a function called sqlite3_commit_hook() which is slightly diff in documentation. Are there any function exposed for this purpose? or What is the way to achieve this behaviour? Can you help me with the best approach of doing this. Regards, Arjun

  Read the article

• Given a few strings, how many strings can be lexicographically least by modifying the alphabet?

  - by Jackson W

  Number of strings can be huge as in 30000. Given N strings, output which ones can be lexicographically least after modifying the english alphabet. e.g. acdbe...... for example if the strings were: omm moo mom ommnom "mom" is already lexicographically least with the original english alphabet. we can make the word "omm" least by switching "m" and "o" in the alphabet ("abcdefghijklonmpqrstuvwxyz"). the other ones you cant make lexicographically last, no matter what you do. any fast way to do this? I have no ways to approach this except try every single possible alphabet

  Read the article

• Reuse C++ Header files

  - by Amrish

  Guys, I have a Visual C++ solution with 2 projects AlgorithmA & AlgorithmB and both share a common header file RunAlgo.h with the class declaration. Each project in the solution has its own unique implementation for the header file. I am trying to compile a DLL out of the common header file RunAlgo.h and add reference to this DLL in the projects AlgorithmA & AlgorithmB. I have then included separate RunAlgo.cpp definition file in both my projects. The problem is that I am getting linker errors while compiling the new DLL project which has only the header file. So, the question is Can a header file with only class declaration be compiled into a DLL (Similar to class library containing an Interface in C#)? For the above scenario, is there a better approach to reuse the common Header file among projects? Should the above method work (re-check my code?)

  Read the article

• How often should we write unit tests?

  - by Midnight Blue

  Hi, I am recently introduced to the test-driven approach to development by my mentor at work, and he encourages me to write an unit-test whenenver "it makes sense." I understand some benefits of having a throughout unit-test suite for both regression testing and refractoring, but I do wonder how often and how throughout we should write unit-test. My mentor/development lead asks me to write a new unit test-case for a newly written control flow in a method that is already being tested by the exsisting test class, and I think it is an overkill. How often do you write your unit tests, and how detailed do you think your unit tests should be? Thanks!

  Read the article

• Picking apples off a tree

  - by John Retallack

  I have the following problem: I am given a tree with N apples, for each apple I am given it's weight and height. I can pick apples up to a given height H, each time I pick an apple the height of every apple is increased with U. I have to find out the maximum weight of apples I can pick. 1 = N = 100000 0 < {H, U, apples' weight and height, maximum weight} < 231 Example: N=4 H=100 U=10 height weight 82 30 91 10 93 5 94 15 The answer is 45: first pick the apple with the weight of 15 then the one with the weight of 30. Could someone help me approach this problem?

  Read the article

• Is there a programming language with be semantics close to English ?

  - by ivo s

  Most languages allow to 'tweek' to certain extend parts of the syntax (C++,C#) and/or semantics that you will be using in your code (Katahdin, lua). But I have not heard of a language that can just completely define how your code will look like. So isn't there some language which already exists that has such capabilities to override all syntax & define semantics ? Example of what I want to do is basically from the C# code below: foreach(Fruit fruit in Fruits) { if(fruit is Apple) { fruit.Price = fruit.Price/2; } } I want do be able to to write the above code in my perfect language like this: Check if any fruits are Macintosh apples and discount the price by 50%. The advantages that come to my mind looking from a coder's perspective in this "imaginary" language are: It's very clear what is going on (self descriptive) - it's plain English after all even kid would understand my program Hides all complexities which I have to write in C#. But why should I care to learn that if statements, arithmetic operators etc since there are already implemented The disadvantages that I see for a coder who will maintain this program are: Maybe you would express this program differently from me so you may not get all the information that I've expressed in my sentence Programs can be quite verbose and hard to debug but if possible to even proximate this type of syntax above maybe more people would start programming right? That would be amazing I think. I can go to work and just write an essay to draw a square on a winform like this: Create a form called MyGreetingForm. Draw a square with in the middle of MyGreetingFormwith a side of 100 points. In the middle of the square write "Hello! Click here to continue" in Arial font. In the above code the parser must basically guess that I want to use the unnamed square from the previous sentence, it'd be hard to write such a smart parser I guess, yet it's so simple what I want to do. If the user clicks on square in the middle of MyGreetingForm show MyMainForm. In the above code 'basically' the compiler must: 1)generate an event handler 2) check if there is any square in the middle of the form and if there is - 3) hide the form and show another form It looks very hard to do but it doesn't look impossible IMO to me at least approximate this (I can personally generate a parser to perform the 3 steps above np & it's basically the same that it has to do any way when you add even in c# a.MyEvent=+handler; so I don't see a problem here) so I'm thinking maybe somebody already did something like this ? Or is there some practical burden of complexity to create such a 'essay style' programming language which I can't see ? I mean what's the worse that can happen if the parser is not that good? - your program will crash so you have to re-word it:)

  Read the article

• typeof === "undefined" vs. != null

  - by Thor Thurn

  I often see JavaScript code which checks for undefined parameters etc. this way: if (typeof input !== "undefined") { // do stuff } This seems kind of wasteful, since it involves both a type lookup and a string comparison, not to mention its verbosity. It's needed because 'undefined' could be renamed, though. My question is: How is that code any better than this approach: if (input != null) { // do stuff } As far as I know, you can't redefine null, so it's not going to break unexpectedly. And, because of the type-coercion of the != operator, this checks for both undefined and null... which is often exactly what you want (e.g. for optional function parameters). Yet this form does not seem widespread, and it even causes JSLint to yell at you for using the evil != operator. Why is this considered bad style?

  Read the article

• 'is instanceof' Interface bad design

  - by peterRit

  Say I have a class A class A { Z source; } Now, the context tells me that 'Z' can be an instance of different classes (say, B and C) which doesn't share any common class in their inheritance tree. I guess the naive approach is to make 'Z' an Interface class, and make classes B and C implement it. But something still doesn't convince me because every time an instance of class A is used, I need to know the type of 'source'. So all finishes in multiple 'ifs' making 'is instanceof' which doesn't sound quite nice. Maybe in the future some other class implements Z, and having hardcoded 'ifs' of this type definitely could break something. The escence of the problem is that I cannot resolve the issue by adding functions to Z, because the work done in each instance type of Z is different. I hope someone can give me and advice, maybe about some useful design pattern. Thanks

  Read the article

• [Android] GPS can't run inside TimerTask

  - by user568553

  Hi, I am trying to write an android app that acquires a GPS signal at a fix time interval, for example every 1 minute. Since the requestLocationUpdate function does not exactly implement that, I tried to use task to accomplished it. public class getGPS extends TimerTask{ public void run(){ System.out.println("Running a GPS task"); locHandler = new locationUpdateHandler(); myManager.requestLocationUpdates(provider, 60000, 0, locHandler); } } public void LoadCoords(){ Timer timer = new Timer(); timer.scheduleAtFixedRate(new getGPS(), 0, 60000); } However, from what I've seen, requestLocationUpdates would run fine if I put it inside LoadCoords(), but would not run if I put it inside the TimerTask (ie no green icon on the task bar to show that GPS is looking for a fix). Can anyone please suggest an alternative approach or pseudo-code, or correct my mistake if there is one ? Thank you in advance.

  Read the article

• WithEvents LinkedList is it Impossible?

  - by serhio

  What is the optimal approach to a WithEvents Collection - VB.NET? Have you any remarks on the code bellow (skipping the Nothing verifications)? The problem is when I obtain the LinkedListNode(Of Foo) in a For Each block I can set myNode.Value = something, and here is a handlers leak... -Could I override the FooCollection's GetEnumerator in this case? -No. :( cause NotInheritable Class LinkedListNode(Of T) Class Foo Public Event SelectedChanged As EventHandler End Class Class FooCollection Inherits LinkedList(Of Foo) Public Event SelectedChanged As EventHandler Protected Overloads Sub AddFirst(ByVal item As Foo) AddHandler item.SelectedChanged, AddressOf OnSelectedChanged MyBase.AddFirst(item) End Sub Protected Overloads Sub AddLast(ByVal item As Foo) AddHandler item.SelectedChanged, AddressOf OnSelectedChanged MyBase.AddLast(item) End Sub ' ------------------- ' Protected Overloads Sub RemoveFirst() RemoveHandler MyBase.First.Value.SelectedChanged, _ AddressOf OnSelectedChanged MyBase.RemoveFirst() End Sub Protected Overloads Sub RemoveLast(ByVal item As Foo) RemoveHandler MyBase.Last.Value.SelectedChanged, _ AddressOf OnSelectedChanged MyBase.RemoveLast() End Sub ' ------------------- ' Protected Sub OnSelectedChanged(ByVal sender As Object, ByVal e As EventArgs) RaiseEvent SelectedChanged(sender, e) End Sub End Class

  Read the article

• image on top of button android

  - by N-AccessDev

  Is it possible to add an image(view) on top of a button (which as a background image)? I'm porting an iOS app to Android and it wasn't a problem on iOS, but I'm wondering if it is the right approach on Android because of layouts. Edit : To clarify, check this screen shot : http://a4.mzstatic.com/us/r1000/062/Purple/v4/7c/4b/cd/7c4bcd53-ba55-94d7-a26c-ce1bfe040003/mza_2736801523527387264.320x480-75.jpg I need to do the bottom left button "carte" (card in french) I need : a button with a background image an image displayed on top of the button which is loaded from internet (a card , there is a lot of different and news cards are added daily, in the screnshot it s "MIDI PASS" ) a text localised on the button , so I cant use Imagebutton class.

  Read the article

• Serving large generated files using Google App Engine?

  - by John Carter

  Hiya, Presently I have a GAE app that does some offline processing (backs up a user's data), and generates a file that's somewhere in the neighbourhood of 10 - 100 MB. I'm not sure of the best way to serve this file to the user. The two options I'm considering are: Adding some code to the offline processing code that 'spoofs' it as a form upload to the blob store, and going thru the normal blobstore process to serve the file. Having the offline processing code store the file somewhere off of GAE, and serving it from there. Is there a much better approach I'm overlooking? I'm guessing this is functionality that isn't well suited to GAE. I had thought of storing in the datastore as db.Text or Dd.Blob but there I encounter the 1 MB limit. Any input would be appreciated,

  Read the article

• Objects instead of global variables in Perl

  - by Gaurav Dadhania

  I don't know if this is the right thing to do. But I'm lookig for tutorials/articles on using objects instead of global variables to store state. For eg. package something # some code here... # that generates errors and uses # something::errors to track errors. package something::errors sub new { my ($this) = @_; bless $this; return $this; } sub setErrors{ my ($this, @errors) = @_; $this->{errors} = \@errors; } sub getErrors{ my ($this) = @_; return $this->{errors}; } Is this better than using global varibles? Any down-sides to this? Any approach which might be better? Thanks.

  Read the article

• Relational databases are not suited for my application - what's the alternative?

  - by waitinforatrain

  Hi, I'm writing a CMS in PHP that allows the user to define different fields (e.g. a Blog page could have fields for Title (string), Content (rich text), Picture (file)). I need the user to be able to add and remove fields dynamically, and the only way I can think of to do it with relational DBs is to serialise all these values and store them in one cell. This seems like a slow approach and like I'm trying to fit something dynamic within a static structure. Could someone recommend anything that is PHP-compatible that would make this easier?

  Read the article

• Comments on this assumption about running on dev server vs a real instance in app engine (python)?

  - by Jacob Oscarson

  Hello app engineers! I'm on an app engine project where I'd like to put in a link to a Javascript test runner that I'd like to only exist when running the development server. I've made some experiments on a local shell with configuration loaded using the technique found in NoseGAE versus live on the 'App Engine Console' [1] and it looks to me like a distinction btw real instance and dev server is the presence of the module google.appengine.tools. Which lead me to this utility function: def is_dev(): """ Tells us if we're running under the development server or not. :return: ``True`` if the code is running under the development server. """ try: from google.appengine import tools return True except ImportError: return False The question (finally!) would be: is this a bad idea? And in that case, can anyone suggest a better approach? [1] http://con.appspot.com/console/ (try it! very handy indeed)

  Read the article

• Use multiple css files or a single file organised by comments

  - by David

  Hi, what is regarded as the best approach to organising css. At the moment I am using a single link in the head of my xhtml documents as follows: <link rel="stylesheet" type="text/css" href="style/imports.css" /> In this file im importing several different css files i.e. reset.css, structure.css, skin.css I know there is an overhead in doing this as each requires an extra trip to the server but it makes things much more logical and organised in my opinion. Does anyone have an opinion on how best to organise their css. - Would it be better to put all these seperate css funcions into one single file? Also, is it best practice to minify css.

  Read the article

• Validate XML instance document against WSDL

  - by Ice09

  Hi, I can easily validate a XML document against a XML Schema, eg. with XMLSpy or programmatically. Is it possible to do this with a WSDL file? It does not seem possible with XMLSpy or any other XML tool I know. For me the only possibility right now is to do it programmatically, eg. by generating Java code from the WSDL and starting a request, which is then marshalled correctly. If there is no tool / easy programmatic approach, is there a tool which can extract XML Schema from the WSDL? Best

  Read the article

• Import Data from Excel Spreadsheet or CVS into MySQL

  - by Kelly Roper

  I have a spreadsheet which really has only one complicated table. I basically convert the spreadsheet to a cvs and use a groovy script to generate the INSERT scripts. However, I cannot do this with a table that has 28 fields with data within some of the fields on the spreadsheet that make importing into the CVS even more complicated. So the fields in the new CVS are not differentiated properly or my script has not accounted for it. Does anyone have any suggestions on a better approach to do this? Thanks.

  Read the article

• Python - List and Loop in one def

  - by Dunwitch

  I'm trying to get the def wfsc_pod1 and wfsc_ip into the same def. I'm not quite sure how to approach the problem. I want wfsc_pod1 to display all the information for name, subnet and gateway. Then wfsc_ip shows the ip addresses below it. I also get a None value when I run it as it. Not sure why. Anything more pythonic is more appreciated. class OutageAddress: subnet = ["255.255.255.0", "255.255.255.1"] # Gateway order is matched with names gateway = ["192.168.1.1", "192.168.1.2", "192.168.1.3", "192.168.1.4", "192.168.1.5", "192.168.1.6", "192.168.1.7", "192.168.1.8", "192.168.1.9"] name = ["LOC1", "LOC2", "LOC3", "LOC4", "LOC5", "LOC6", "LOC7", "LOC8", "LOC9"] def wfsc_pod1(self): wfsc_1 = "%s\t %s\t %s\t" % (network.name[0],network.subnet[0],network.gateway[0]) return wfsc_1 def wfsc_ip(self): for ip in range(100,110): ip = "192.168.1."+str(ip) print ip network = OutageAddress() print network.wfsc_pod1() print network.wfsc_ip()

  Read the article

• Django startup importing causes reverse to happen

  - by nicknack

  This might be an isolated problem, but figured I'd ask in case someone has thoughts on a graceful approach to address it. Here's the setup: -------- views.py -------- from django.http import HttpResponse import shortcuts def mood_dispatcher(request): mood = magic_function_to_guess_my_mood(request) return HttpResponse('Please go to %s' % shortcuts.MOODS.get(mood, somedefault)) ------------ shortcuts.py ------------ MOODS = # expensive load that causes a reverse to happen The issue is that shortcuts.py causes an exception to be thrown when a reverse is attempted before django is done building the urls. However, views.py doesn't yet need to import shortcuts.py (used only when mood_dispatcher is actually called). Obvious initial solutions are: 1) Import shortcuts inline (just not very nice stylistically) 2) Make shortcuts.py build MOODS lazily (just more work) What I ideally would like is to be able to say, at the top of views.py, "import shortcuts except when loading urls"

  Read the article

• How to correctly do SQL UPDATE with weighted subselect?

  - by luminarious

  I am probably trying to accomplish too much in a single query, but have I an sqlite database with badly formatted recipes. This returns a sorted list of recipes with relevance added: SELECT *, sum(relevance) FROM ( SELECT *,1 AS relevance FROM recipes WHERE ingredients LIKE '%milk%' UNION ALL SELECT *,1 AS relevance FROM recipes WHERE ingredients LIKE '%flour%' UNION ALL SELECT *,1 AS relevance FROM recipes WHERE ingredients LIKE '%sugar%' ) results GROUP BY recipeID ORDER BY sum(relevance) DESC; But I'm now stuck with a special case where I need to write the relevance value to a field on the same row as the recipe. I figured something along these lines: UPDATE recipes SET relevance=(SELECT sum(relevance) ...) But I have not been able to get this working yet. I will keep trying, but meanwhile please let me know how you would approach this?

  Read the article

• Is it a good idea to use only a key to encrypt an entire (small) filesystem?

  - by Fernando Miguélez

  This question comes as part of my doubts presented on a broader question about ideas implementing a small encrypted filesystem on Java Mobile phones (J2ME, BlackBerry, Android). Provided the litte feedback received, considering the density of the question, I decided to divide those doubts into small questions. So to sum up I plan to "create" an encrypted filesystem for for mobile phones (with the help of BoucyCastle or a subset of JCE), providing an API that let access to them in a transparent way. Encryption would be carried out on a file basis (not blocks). My question is this: Is it a good idea to use only a simmetric key (maybe AES-256) to encrypt all the files (they wouldn't be that many, maybe tens of them) and store this key in a keystore (protected by a pin) or would you rather encrypt each file with an on-the-fly generated key stored alongside each file, encrypting that key with the "master" key stored on the keystore? What are the benefits/drawbacks of each approach?

  Read the article

< Previous Page | 276 277 278 279 280 281 282 283 284 285 286 287  | Next Page >