Search Results

Search found 5521 results on 221 pages for 'deeper understanding'.

Page 17/221 | < Previous Page | 13 14 15 16 17 18 19 20 21 22 23 24  | Next Page >

  • understanding list[i-1] vs list[i]-1

    - by user3720527
    Hopefully this is a simple answer that I am just failing to understand. Full code is public static void mystery(int[] list) { for( int i = list.length - 1; i>1; i --) { if (list[i] > list[i - 1]) { list[i -1] = list[i] - 2; list[i]++; } } } } and lets say we are using a list of [2,3,4]. I know that it will output 2,2,5 but I am unclear how to actually work through it. I understand that the list.length is 3 here, and I understand that the for loop will only run once, but I am very unclear what happens at the list[i - 1] = list[i] - 2; area. Should it be list[2-1] = list[2] - 2? How does the two being outside the bracket effect it differently? Much thanks.

    Read the article

  • Understanding Plesk Watchdog statistics

    - by weotch
    We have Plesk 8.3 installed. I've started using their Watchdog module to track server useage. Our server routinely has trouble with the amount of traffic we have and I think our MySQL queries need to be smarter. Anyway, looking at the stats from Watchdog, it seems like MySQL usage is low compared to so something else making up the "overall" usage. See this: I was hoping someone with a lot of Plesk exeprience could help me understand what I'm seeing here. Can I not trust Watchdog's reports or am I missing something?

    Read the article

  • understanding z buffer formates direct x

    - by numerical25
    A z buffer is just a 3d array that shows what object should be written in front of another object. each element in the array represents a pixel that holds a value from 0.0 to 1.0. My question is if that is all a z buffer does, then why are some buffers 24bit, 32bit, and 16 bit ??

    Read the article

  • Understanding top output in Linux

    - by Rayne
    Hi, I'm trying to determine the CPU usage of a program by looking at the output from Top in Linux. I understand that %us means userspace and %sy means system/kernel etc. But say I see 100%us. Does this mean that the CPU is really only doing useful work? What if a CPU is tied up waiting for resources that are not avaliable, or cache misses, would it also show up in the %us column, or any other column? Thank you.

    Read the article

  • Am I understanding premature optimization correctly?

    - by Ed Mazur
    I've been struggling with an application I'm writing and I think I'm beginning to see that my problem is premature optimization. The perfectionist side of me wants to make everything optimal and perfect the first time through, but I'm finding this is complicating the design quite a bit. Instead of writing small, testable functions that do one simple thing well, I'm leaning towards cramming in as much functionality as possible in order to be more efficient. For example, I'm avoiding multiple trips to the database for the same piece of information at the cost of my code becoming more complex. One part of me wants to just not worry about redundant database calls. It would make it easier to write correct code and the amount of data being fetched is small anyway. The other part of me feels very dirty and unclean doing this. :-) I'm leaning towards just going to the database multiple times, which I think is the right move here. It's more important that I finish the project and I feel like I'm getting hung up because of optimizations like this. My question is: is this the right strategy to be using when avoiding premature optimization?

    Read the article

  • I need help understanding how this jQuery filter function works, line-by-line, if possible

    - by user717236
    Here is the HTML: <div> <h3>text</h3> </div> <div> <h3>moretext</h3> </div> <div> <h3>123</h3> </div>?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? Here is the JS: var rv1_wlength = $("div").filter(function() { return $(this).find("h3").filter(function () { return $(this).text() != "123"; }).length; }); var rv1_wolength = $("div").filter(function() { return $(this).find("h3").filter(function () { return $(this).text() != "123"; }); }); var rv2 = $("div").find("h3").filter(function() { return $(this).text() != "123"; }); alert(rv1_wlength.text()); // text // moretext alert(rv1_wolength.text()); // text // moretext // 123 alert(rv2.text());? // textmoretext I don't understand why the first two methods print the elements on each line, whereas the second method concatenates them. "rv2" is a jQuery object. Then, what are the first two (rv1_wlength and rv1_wolength)? Furthermore, I don't understand why the inclusion of the length property makes all the difference in filtering the elements. The second method does nothing, since it returns all the elements. The first method, with the only change being the addition of the length property, correctly filters the elements. I would very much like a line-by-line explanation. I would sincerely appreciate any feedback. Thank you.

    Read the article

  • Having trouble understanding some code (Ruby on Rails)

    - by user284194
    I posted a question awhile ago asking how I could limit the rate at which a form could be submitted from a rails application. I was helped by a very patient user and their solution works great. The code was for my comments controller, and now I find myself wanting to add this functionality to another controller, my Messages controller. I immediately tried reusing the working code from the comments controller but I couldn't get it to work. Instead of asking for the working code, could someone please help me understand my working comment controller code? class CommentsController < ApplicationController #... before_filter :post_check def record_post_time cookies[:last_post_at] = Time.now.to_i end def last_post_time Time.at((cookies[:last_post_at].to_i rescue 0)) end MIN_POST_TIME = 2.minutes def post_check return true if (Time.now - last_post_time) > MIN_POST_TIME flash[:warning] = "You are trying to reply too fast." @message = Message.find(params[:message_id]) redirect_to(@message) return false end #... def create @message = Message.find(params[:message_id]) @comment = @message.comments.build(params[:comment]) if @comment.save record_post_time flash[:notice] = "Replied to \"#{@message.title}\"" redirect_to(@message) else render :action => "new" end end def update @message = Message.find(params[:message_id]) @comment = Comment.find(params[:id]) if @comment.update_attributes(params[:comment]) record_post_time redirect_to post_comment_url(@message, @comment) else render :action => "edit" end end #... end My Messages controller is pretty much a standard rails generated controller with a few before filters and associated private methods for DRYing up the code and a redirect for non existent pages. I'll explain how much of the code I understand. When a comment is created, a cookie is created with a last_post_time value. If they try to post another comment, the cookie is checked if the last one was made in the last two minutes. If it was a flash warning is displayed and no comment is recorded. What I don't really understand is how the post_check method works and how I can adapt it for my simpler posts controller. I thought I could reuse all the code in the message controller with the exception of the line: @message = Message.find(params[:message_id]) # (don't need the redirect code) in the post_check method. But it trips up on the "record_post_time" in the create action/method. I really want to understand this. Can someone explain why this doesn't work? I greatly appreciate you reading my lengthy question.

    Read the article

  • Understanding EXE Internals

    - by Steve
    I was attempting to install an exe that requires a serial number before the install, which the vendor has not provided to us yet. This got my wheels turning about whether there is any information that can be gained from viewing an exe using a hex editor/VI/etc? Using VI to view an exe, I can see some sections of plain text, but it is difficult to determine what it refers to without any context around it. Is it possible to determine any information by reading an exe? Thanks

    Read the article

  • Understanding Async Concept in WebServices

    - by 8EM
    I've had the thrill recently of developing web service applications. Most of my experience is with GWT and mainly doing most things on the client side then doing an async call back for any additional data needed. However at the moment, I want a process that will be triggered on the client side, then on the server side, a loop will occur, where if a certain condition is met, it will 'push' back to the client. This will hopefully remove the processor usage on the client side and also saves bandwidth. What is this called? I understand 'polling' is where the client side continuously hits a server, however what I want is the opposite. Is this possible? Am I misunderstanding what happened when I trigger an AsyncService in GWT? Please advise. EDIT: Just for further clarification: Having some kind of weather data service. Where, you trigger 'go' on the client side, then on the server side, it checks to see the degrees, if it has moved since last time, it will spit back the degrees to the client, if it hasn't, it will keep looping.

    Read the article

  • Understanding C++ dynamic allocation

    - by kiokko89
    Consider the following code: class CString { private: char* buff; size_t len; public: CString(const char* p):len(0), buff(nullptr) { cout << "Constructor called!"<<endl; if (p!=nullptr) { len= strlen(p); if (len>0) { buff= new char[len+1]; strcpy_s(buff, len+1, p); } } } CString (const CString& s) { cout << "Copy constructor called!"<<endl; len= s.len; buff= new char[len+1]; strcpy_s(buff, len+1, s.buff); } CString& operator = (const CString& rhs) { cout << "Assignment operator called!"<<endl; if (this != &rhs) { len= rhs.len; delete[] buff; buff= new char[len+1]; strcpy_s(buff, len+1, rhs.buff); } return *this; } CString operator + (const CString& rhs) const { cout << "Addition operator called!"<<endl; size_t lenght= len+rhs.len+1; char* tmp = new char[lenght]; strcpy_s(tmp, lenght, buff); strcat_s(tmp, lenght, rhs.buff); return CString(tmp); } ~CString() { cout << "Destructor called!"<<endl; delete[] buff; } }; int main() { CString s1("Hello"); CString s2("World"); CString s3 = s1+s2; } My problem is that I don't know how to delete the memory allocated in the addition operator function(char* tmp = new char[length]). I couldn't do this in the constructor(I tried delete[] p) because it is also called from the main function with arrays of chars as parameters which are not allocated on the heap...How can I get around this? (Sorry for my bad English...)

    Read the article

  • C: Global ,Static variables understanding

    - by pavun_cool
    Hi All, In following program . I have one doubt. I have declared one global variable . I am printing the address of the global variable in the function . It is giving me same address when I am not changing the value of global . If I did any changes in the global variables It is giving me different address why...........? Like that it is happening for static also. #include<stdio.h> int global=10 ; // Global variables void function(); main() { global=20; printf ( " %p \n" , global ) ; printf ( " Val: %d\n", global ) ; function(); new(); } void function() { global=30; printf ( " %p \n" , global ) ; printf ( " Val: %d\n", global ) ; } Thanks.

    Read the article

  • Project Euler 9 Understanding

    - by DMan
    This question states: A Pythagorean triplet is a set of three natural numbers, a b c, for which, a2 + b2 = c2 For example, 32 + 42 = 9 + 16 = 25 = 52. There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product abc. I'm not sure what's it trying to ask you. Are we trying to find a^2+b^2=c^2 and then plug those numbers into a+b+c=1000?

    Read the article

  • Need help understanding some Python code

    - by Yarin
    I'm new to Python, and stumped by this piece of code from the Boto project: class SubdomainCallingFormat(_CallingFormat): @assert_case_insensitive def get_bucket_server(self, server, bucket): return '%s.%s' % (bucket, server) def assert_case_insensitive(f): def wrapper(*args, **kwargs): if len(args) == 3 and not (args[2].islower() or args[2].isalnum()): raise BotoClientError("Bucket names cannot contain upper-case " \ "characters when using either the sub-domain or virtual " \ "hosting calling format.") return f(*args, **kwargs) return wrapper Trying to understand what's going on here. What is the '@' symbol in @assert_case_sensitive ? What do the args *args, **kwargs mean? What does 'f' represent? Thanks!

    Read the article

  • Need a hand understanding this Java code please :-)

    - by Brian
    Hi all, Just wondering if anyone would be able to take a look at this code for implementing the quicksort algorithm and answer me a few questions, please :-) public class Run { /*************************************************************************** * Quicksort code from Sedgewick 7.1, 7.2. **************************************************************************/ public static void quicksort(double[] a) { //shuffle(a); // to guard against worst-case quicksort(a, 0, a.length - 1, 0); } static void quicksort(final double[] a, final int left, final int right, final int tdepth) { if (right <= left) return; final int i = partition(a, left, right); if ((tdepth < 4) && ((i - left) > 1000)) { final Thread t = new Thread() { public void run() { quicksort(a, left, i - 1, tdepth + 1); } }; t.start(); quicksort(a, i + 1, right, tdepth + 1); try { t.join(); } catch (InterruptedException e) { throw new RuntimeException("Cancelled", e); } } else { quicksort(a, left, i - 1, tdepth); quicksort(a, i + 1, right, tdepth); } } // partition a[left] to a[right], assumes left < right private static int partition(double[] a, int left, int right) { int i = left - 1; int j = right; while (true) { while (less(a[++i], a[right])) // find item on left to swap ; // a[right] acts as sentinel while (less(a[right], a[--j])) // find item on right to swap if (j == left) break; // don't go out-of-bounds if (i >= j) break; // check if pointers cross exch(a, i, j); // swap two elements into place } exch(a, i, right); // swap with partition element return i; } // is x < y ? private static boolean less(double x, double y) { return (x < y); } // exchange a[i] and a[j] private static void exch(double[] a, int i, int j) { double swap = a[i]; a[i] = a[j]; a[j] = swap; } // shuffle the array a[] private static void shuffle(double[] a) { int N = a.length; for (int i = 0; i < N; i++) { int r = i + (int) (Math.random() * (N - i)); // between i and N-1 exch(a, i, r); } } // test client public static void main(String[] args) { int N = 5000000; // Integer.parseInt(args[0]); // generate N random real numbers between 0 and 1 long start = System.currentTimeMillis(); double[] a = new double[N]; for (int i = 0; i < N; i++) a[i] = Math.random(); long stop = System.currentTimeMillis(); double elapsed = (stop - start) / 1000.0; System.out.println("Generating input: " + elapsed + " seconds"); // sort them start = System.currentTimeMillis(); quicksort(a); stop = System.currentTimeMillis(); elapsed = (stop - start) / 1000.0; System.out.println("Quicksort: " + elapsed + " seconds"); } } My questions are: What is the purpose of the variable tdepth? Is this considered a "proper" implementation of a parallel quicksort? I ask becuase it doesn't use implements Runnable or extends Thread... If it doesn't already, is it possible to modify this code to use multiple threads? By passing in the number of threads you want to use as a parameter, for example...? Many thanks, Brian

    Read the article

  • Understanding Nested If.. Else statements

    - by user1174762
    For some reason my PHP login script keeps returning "invalid email/password combination", yet i know I am entering the correct email and password. Does anyone see what I might be doing wrong? <?php $email= $_POST['email']; $password= $_POST['password']; if (!empty($email) && !empty($password)) { $connect= mysqli_connect("localhost", "root", "", "si") or die('error connecting with the database'); $query= "SELECT user_id, email, password FROM users WHERE email='$email' AND password='$password'"; $result= mysqli_query($connect, $query) or die('error with query'); if (mysqli_num_rows($result) == 1) { $row= mysqli_fetch_array($result); setcookie('user_id', $row['user_id']); echo "you are now logged in"; } else { echo "invalid username/password combination"; } } else { echo" you must fill out both username and password"; } ?>

    Read the article

  • Still not understanding SVN Repositories in eclipse

    - by jax
    I am about to import my project into svn but don't want to stuff it up. My structure is like this: Repositories: /var/svn/client_name1/ /var/svn/client_name2/ Project directories under /var/svn/client_name1/ project1/ trunk/ branches/ tags/ project2/ trunk/ branches/ tags/ My Apache config looks like this: <Location /svn> DAV svn SVNParentPath /var/svn SVNListParentPath on AuthType Basic AuthName "My Repository" AuthUserFile /etc/svnpass Require valid-user AuthzSVNAccessFile /etc/svnauth </Location> Now I can access my svn repository http://mysite.com/svn/client_name1/ however, there are no projects displayed here, just a Revision 0 message (is that correct)? I can connect to the repository in eclipse using the same url. If I want to place an existing project into the repository what url do I use? http://mysite.com/svn/client_name1/project1 OR http://mysite.com/svn/client_name1/project1/trunk

    Read the article

  • Understanding Clojure concurrency example

    - by dusha
    Hello, I just go through various documentation on Clojure concurrency and came accross the example on the website (http://clojure.org/concurrent_programming). (import '(java.util.concurrent Executors)) (defn test-stm [nitems nthreads niters] (let [refs (map ref (replicate nitems 0)) pool (Executors/newFixedThreadPool nthreads) tasks (map (fn [t] (fn [] (dotimes [n niters] (dosync (doseq [r refs] (alter r + 1 t)))))) (range nthreads))] (doseq [future (.invokeAll pool tasks)] (.get future)) (.shutdown pool) (map deref refs))) I understand what it does and how it works, but I don't get why the second anonymous function fn[] is needed? Many thanks, dusha. P.S. Without this second fn [] I get NullPointerException.

    Read the article

  • Trouble understanding Java map Entry sets

    - by Jake Sellers
    I'm looking at a java hangman game here: https://github.com/leleah/EvilHangman/blob/master/EvilHangman.java The code in particular is this: Iterator<Entry<List<Integer>, Set<String>>> k = partitions.entrySet().iterator(); while (k.hasNext()) { Entry<?, ?> pair = (Entry<?, ?>)k.next(); int sizeOfSet = ((Set<String>)pair.getValue()).size(); if (sizeOfSet > biggestPartitionSize) { biggestPartitionSize = sizeOfSet; } } Now my question. My google foo is weak I guess, I cannot find much on Entry sets other than the java doc itself. Is is just a temporary copy of the map? And I cannot find any info at all on the syntax: Entry<?, ?> Can anyone explain or point me toward an explanation of what is going on with those question marks? Thanks in advanced.

    Read the article

  • understanding memory mapping in directx

    - by numerical25
    So my question is ... " When your using the mapping feature to write into a memory buffer, are you really just saving the whole procedure into a queue so directX executes it when finished with other tasks???" I ask this question because this is my perception of mapping when writing to a buffer. I just want to make sure my perception is correct. I understand that the monitor moves extremely slow in compared to the processor, and I am sure the processor can execute 10 times the amount the screen can refresh. So is this one of the reason you should map when writing to a buffer. so each procedure can be done in a orderly fashion. If someone could elaborate, that would be great. thanks

    Read the article

  • Understanding CGI and SQL security from the ground up

    - by Steve
    This question is for learning purposes. Suppose I am writing a simple SQL admin console using CGI and Python. At http://something.com/admin, this admin console should allow me to modify a SQL database (i.e., create and modify tables, and create and modify records) using an ordinary form. In the least secure case, anybody can access http://something.com/admin and modify the database. You can password protect http://something.com/admin. But once you start using the admin console, information is still transmitted in plain text. So then you use HTTPS to secure the transmitted data. Questions: To describe to a learner, how would you incrementally add security to the least secure environment in order to make it most secure? How would you modify/augment my three (possibly erroneous) steps above? What basic tools in Python make your steps possible? Optional: Now that I understand the process, how do sophisticated libraries and frameworks inherently achieve this level of security?

    Read the article

  • Understanding the concept of Inodes

    - by darkie15
    Hi All, I am referring to the link: http://www.tux4u.nl/freedocs/unix/draw/inode.pdf I am confused on parts: 1 12 direct block pointers 2 1 single indirect block pointer 3 1 double indirect block pointer 4 1 triple indirect block pointer Now the diagram says that each pointer is 32/64 bits. [Query]: Why and how are these values inferred? I mean why specifically have only 32 or 64 bit pointers? The diagram says, One data block{8 KB} for each pointer {4 bytes/8 bytes} [Query]: How does this actually work out? i.e. 8*1024 bytes / 8 bytes = 1024 bytes? What is the logic behind having a 8 bytes pointer for 8KB block? Regards, darkie.

    Read the article

  • Understanding character encoding in typical Java web app

    - by Marcus
    Some pseudocode from a typical web app: String a = "A bunch of text"; //UTF-16 saveTextInDb(a); //Write to Oracle VARCHAR(15) column String b = readTextFromDb(); //UTF-16 out.write(b); //Write to http response In the first line we create a Java String which uses UTF-16. When you save to Oracle VARCHAR(15) does Oracle also store this as UTF-16? Does the length of an Oracle VARCHAR refer to number of Unicode characters (and not number of bytes)? And then when we write b to the ServletResponse is this being written as UTF-16 or are we by default converting to another encoding like UTF-8?

    Read the article

  • Java - understanding servlets

    - by Trup
    I am working on a homework project that should implement a board game between 2 clients over an HttpServlet. I have couple of questions: 1) I read that HttpServlets must be stateless, however, for the sake of the game, I have to keep a lot of state(whose turn it is, the state of the board, etc). Do I have to keep this in the clients? Does the HttpServlet indeed have to be stateless, i.e. have no fields that track state? 2) I know that the clients will talk to the servlet via the doGet/doPost methods, but how can the servlet talk to the clients(for example, if player 1 just made a move and sent it to the servlet, the servlet has to tell client 2 what the move was). Thank you Also, if you can point me to a useful, simple example of a similar code online, I would be very grateful

    Read the article

< Previous Page | 13 14 15 16 17 18 19 20 21 22 23 24  | Next Page >