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  • Inlining an array of non-default constructible objects in a C++ class

    - by porgarmingduod
    C++ doesn't allow a class containing an array of items that are not default constructible: class Gordian { public: int member; Gordian(int must_have_variable) : member(must_have_variable) {} }; class Knot { Gordian* pointer_array[8]; // Sure, this works. Gordian inlined_array[8]; // Won't compile. Can't be initialized. }; As even beginner C++ users know, the language guarantees that all members are initialized when constructing a class. And it doesn't trust the user to initialize everything in the constructor - one has to provide valid arguments to the constructors of all members before the body of the constructor even starts. Generally, that's a great idea as far as I'm concerned, but I've come across a situation where it would be a lot easier if I could actually have an array of non-default constructible objects. The obvious solution: Have an array of pointers to the objects. This is not optimal in my case, as I am using shared memory. It would force me to do extra allocation from an already contended resource (that is, the shared memory). The entire reason I want to have the array inlined in the object is to reduce the number of allocations. This is a situation where I would be willing to use a hack, even an ugly one, provided it works. One possible hack I am thinking about would be: class Knot { public: struct dummy { char padding[sizeof(Gordian)]; }; dummy inlined_array[8]; Gordian* get(int index) { return reinterpret_cast<Gordian*>(&inlined_array[index]); } Knot() { for (int x = 0; x != 8; x++) { new (get(x)) Gordian(x*x); } } }; Sure, it compiles, but I'm not exactly an experienced C++ programmer. That is, I couldn't possibly trust my hacks less. So, the questions: 1) Does the hack I came up with seem workable? What are the issues? (I'm mainly concerned with C++0x on newer versions of GCC). 2) Is there a better way to inline an array of non-default constructible objects in a class?

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  • In an array of buttons, how can you tell which button was clicked?

    - by Michael Seltenreich
    If I have an array of buttons, how can I tell which button was clicked? example below var i=0 CreateButton = new function () { savebutton[i]=NewButton() i++ } every time a user runs the function a new button is generated. the first button is savebutton[0] the second is savebutton[1] and so on potentially infinity times. when later the user presses the button I want the screen to alert it's index number (or 'i'). is there any way to make this work in arrays?

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  • redirection code for cfm script

    - by tibin mathew
    Hi friends, I need a CFM script to place on my website homepage. If a visitor arrives from a search engine using a a certain search phrase, I want to redirect them to various pages. For example: The following searches would redirect to the following pages: become a business coach - http://www.businesscoach.com/BusinessCoaching.html find a business coach - http://www.businesscoach.com/go/bc/find-a-business-coach/index.cfm please help me to do this... Thanks

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  • In MVC framworks (such as Ruby on Rails), do usually Model spell as singular and controller and view

    - by Jian Lin
    I usually see Ruby on Rails books using script/generate model Story name:string link:string which is a singular Story, while when it is controller script/generate controller Stories index then the Story now is Stories, which is plural. Is this a standard on Ruby on Rails? Is it true in other MVC frameworks too, like CakePHP, Symfony, Django, or TurboGears? I see that in the book Rails Space, the controller is also called User, which is the same as the model name, and it is the only exception I see.

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  • python print end=' '

    - by Hath
    i have this python script where i need to run 'gdal_retile.py' but i get this an exception on this line: if Verbose: print(Building internam Index for %d tile(s) ..." % len(inputTiles), end=' ') the end='' is invalid syntax just curious as to why.. and what the author probably meant to do. I'm new to python if you haven't already guessed.

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  • Integrating Zend Controller Standalone - without the rest of Zend Framework

    - by ssmusoke
    I am using specific parts of the Zend Framework in my application, and I would like to replace my home grown controller with a Zend Framework controller. My home grown controller is based on an index.php file to which all requests are submitted. A controller is instantiated based on parameters sent within the request After processing the user is forwarded to url which is based on the request information, either a url is specified or some data is analysed I would like ideas on how to integrate the Zend Controller within my application Thanks in advance

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  • O(log n) algorithm for merging lists and computing rank?

    - by Eternal Learner
    Given two sorted lists, each containing n real numbers, is there a O(log?n) time algorithm to compute the element of rank i (where i coresponds to index in increasing order) in the union of the two lists, assuming the elements of the two lists are distinct? I can think of using a Merge procedure to merge the 2 lists and then find the A[i] element in constant time. But the Merge would take O(n) time. How do we solve it in O(log n) time?

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  • Retrieving substring of a bound value

    - by shivesh
    I am binding some data to control, but want to limit the number of character of a specific field to a 30 first characters. I want to do it, if it's possible, on aspx page. I tried this: Text='<%# String.Format("{0}", Eval("Title")).Substring(0,30) %> ' But got this error: Index and length must refer to a location within the string. Parameter name: length

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  • CSS with a PHP extension?

    - by raj
    I would like to name my css file mystyles.php. All content within will still be css. I'd like to then include this into my index.php page without using the standard HTML <link> tag. Any direction would be appreciated very much.

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  • Is there a way to get direct_to_template to pass RequestContext in django?

    - by BigJason
    I have found myself writing the same view over and over. It is basically this: def home_index(request): return render_to_response('home/index.html', RequestContext(request)) To keep with the dry principal, I would like to utilize a generic view. I have seen direct_to_template, but it passes an empty context. So how can I use a generic view and still get the power of RequestContext?

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  • How to go to particular Item in IEnumerable

    - by Subhen
    Hi, I have Ienum which contains number Data inside it. Attached the snapShot of Viual Studio, Enum that Contains Data: Just to brief about the above image, eLevelData is the IEnumerable variable, in which I have my data . Now I want to go to the data at index 4 or 5, but I don't want to use foreach loop. Any suggestions please. Thanks, Subhen

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  • Is there a way to efficiently yield every file in a directory containing millions of files?

    - by Josh Smeaton
    I'm aware of os.listdir, but as far as I can gather, that gets all the filenames in a directory into memory, and then returns the list. What I want, is a way to yield a filename, work on it, and then yield the next one, without reading them all into memory. Is there any way to do this? I worry about the case where filenames change, new files are added, and files are deleted using such a method. Some iterators prevent you from modifying the collection during iteration, essentially by taking a snapshot of the state of the collection at the beginning, and comparing that state on each move operation. If there is an iterator capable of yielding filenames from a path, does it raise an error if there are filesystem changes (add, remove, rename files within the iterated directory) which modify the collection? There could potentially be a few cases that could cause the iterator to fail, and it all depends on how the iterator maintains state. Using S.Lotts example: filea.txt fileb.txt filec.txt Iterator yields filea.txt. During processing, filea.txt is renamed to filey.txt and fileb.txt is renamed to filez.txt. When the iterator attempts to get the next file, if it were to use the filename filea.txt to find it's current position in order to find the next file and filea.txt is not there, what would happen? It may not be able to recover it's position in the collection. Similarly, if the iterator were to fetch fileb.txt when yielding filea.txt, it could look up the position of fileb.txt, fail, and produce an error. If the iterator instead was able to somehow maintain an index dir.get_file(0), then maintaining positional state would not be affected, but some files could be missed, as their indexes could be moved to an index 'behind' the iterator. This is all theoretical of course, since there appears to be no built-in (python) way of iterating over the files in a directory. There are some great answers below, however, that solve the problem by using queues and notifications. Edit: The OS of concern is Redhat. My use case is this: Process A is continuously writing files to a storage location. Process B (the one I'm writing), will be iterating over these files, doing some processing based on the filename, and moving the files to another location. Edit: Definition of valid: Adjective 1. Well grounded or justifiable, pertinent. (Sorry S.Lott, I couldn't resist). I've edited the paragraph in question above.

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  • Changing default REST routes in Rails 3

    - by Vincent
    I need to add one parameter to the default REST route for the show action for SEO purposes: resources :neighborhoods, :only => [:index, :show] neighborhood_url(neighborhood) # => /neighborhoods/lower-east-side I want something like the following: neighborhood_url(city, neighborhood) # => /neighborhoods/manhattan/lower-east-side What would be the easiest way to do this without using nested routes and without breaking Rails REST conventions?

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  • Java's getResourceAsStream() is always returning null

    - by Andreas Grech
    I have the following structure in a Java Web Application: TheProject -- [Web Pages] -- -- [WEB-INF] -- -- -- abc.txt -- -- index.jsp -- [Source Packages] -- -- [wservices] -- -- -- WS.java In WS.java, I am using the following code in a Web Method: InputStream fstream = this.getClass().getResourceAsStream("abc.txt"); But it is always returning a null. I need to read from that file, and I read that if you put the files in WEB-INF, you can access them with getResourceAsStream, yet the method is always returning a null. Any ideas of what I may be doing wrong?

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  • Wordpress htaccess problem

    - by ajithperuva
    I have some problem with my htaccess file .here am adding my problem.Please help me My actual url is as follows http://localhost/buydualit/?searchitem=toaster&pagenum=1 here by using my .htaccess am rewrited my url as http://localhost/buydualit/toaster-1/ My url rewriting rule is like follows RewriteRule ^[A-Za-z-0-9,\"'-\/]+-([0-9]+)\/$ buydualit/index.php?pagenum=$1&searchitem=$2 In this rule how can i retrieve toaster from http://localhost/buydualit/toaster-1/ (searchitem=$2 which is not getting) please help me

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  • Return the Largest Span in a given Array -Core Java and Arrays Question

    - by Deepak
    Hi Stack People, Merry Christmas and hope you are in great Spirits,I have a Question in Java-Arrays as shown below.Im stuck up with this struggling to get it rite. Consider the leftmost and righmost appearances of some value in an array. We'll say that the "span" is the number of elements between the two inclusive. A single value has a span of 1. Write a **Java Function** that returns the largest span found in the given array. **Example: maxSpan({1, 2, 1, 1, 3}) ? 4,answer is 4 coz MaxSpan between 1 to 1 is 4 maxSpan({1, 4, 2, 1, 4, 1, 4}) ? 6,answer is 6 coz MaxSpan between 4 to 4 is 6 maxSpan({1, 4, 2, 1, 4, 4, 4}) ? 6,answer is 6 coz Maxspan between 4 to 4 is 6 which is greater than MaxSpan between 1 and 1 which is 4,Hence 64 answer is 6. I have the code which is not working,it includes all the Spans for a given element,im unable to find the MaxSpan for a given element. Please help me out. Results of the above Program are as shown below Expected This Run maxSpan({1, 2, 1, 1, 3}) ? 4 5 X maxSpan({1, 4, 2, 1, 4, 1, 4}) ? 6 8 X maxSpan({1, 4, 2, 1, 4, 4, 4}) ? 6 9 X maxSpan({3, 3, 3}) ? 3 5 X maxSpan({3, 9, 3}) ? 3 3 OK maxSpan({3, 9, 9}) ? 2 3 X maxSpan({3, 9}) ? 1 1 OK maxSpan({3, 3}) ? 2 3 X maxSpan({}) ? 0 1 X maxSpan({1}) ? 1 1 OK ::Code:: public int maxSpan(int[] nums) { int count=1;//keep an intial count of maxspan=1 int maxspan=0;//initialize maxspan=0 for(int i=0;i<nums.length;i++){ for(int j=i+1;j<nums.length;j++){ if(nums[i] == nums[j]){ //check to see if "i" index contents == "j" index contents count++; //increment count maxspan=count; //make maxspan as your final count int number = nums[i]; //number=actual number for maxspan } } } return maxspan+1; //return maxspan }

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  • Hash Table question [closed]

    - by Fatimah
    I need your help to solve this program ... Implement a separate chaining hash table that stores strings. You’ll need a hash function that converts string into an index number. Assume the strings will be lowercase words, so 26 characters will suffice.

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  • how properly remove item from list

    - by dygi
    // tmpClientList is List<Client> type if (txtboxClientName.Text != "") foreach (Client cli in tmpClientList) if (cli.Name != txtboxClientName.Text) tmpClientList.Remove(cli); Error: "Collection was modified; enumeration operation may not execute." How can i remove items from the list, in some simple way, without saving indexes of these items in another list or array, and removing them in another place in the code. Tried also RemoveAt(index) but it's exactly the same situation, modifying when loop runs.

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  • url.rewrite-once with Kohana and with urls

    - by mike clagg
    currently I have this setup in our simple-hosts.conf: url.rewrite-once = ( ".*.(js|ico|gif|jpg|png|css|php|htm)(?.*)?$" = "$0", "/slapi" = "/slapi/index.php" ) Works great, except the above fails when I have a dot in the query string: ?url=http://google.com My regexpy is not 1337

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  • .htaccess mod_rewrite subdomains

    - by Aaron
    .htaccess: RewriteEngine On RewriteBase / RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{HTTP_HOST} ^site\.com$ [NC] RewriteRule ^(.*)$ http://www.site.com/$1 [L,R=301] RewriteRule ^new/?$ index.php?section=new This works great and all, but I have recently implemented a subdomain m.site.com which reads off of a /mobile directory. When accessing m.site.com/new it will not display anything except return a server error. What can I do to correct this problem? Basically, I want http://m.site.com/new To achieve the same affect as http://www.site.com/new

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  • Is two-finger non-homerow touch-typing for programming acceptable?

    - by codebliss
    I'm currently typing about 90 wpm (from http://speedtest.10-fast-fingers.com/ 90 correct 0 missed) using two fingers and the occasional ring or index. This probably grew from learning to type at an early age, before home-row was presented to me. Is this acceptable? Do people religiously endorse home-row even with low-mistake poking without looking at the keyboard?

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