Search Results

Search found 16643 results on 666 pages for 'stackoverflow answer'.

Page 420/666 | < Previous Page | 416 417 418 419 420 421 422 423 424 425 426 427  | Next Page >

• What are the lesser known but cool data structures ?

  - by f3lix

  There a some data structures around that are really cool but are unknown to most programmers. Which are they? Everybody knows linked lists, binary trees, and hashes, but what about Skip lists, Bloom filters for example. I would like to know more data structures that are not so common, but are worth knowing because they rely on great ideas and enrich a programmer's tool box. PS: I am also interested on techniques like Dancing links which make interesting use of the properties of a common data structure. EDIT: Please try to include links to pages describing the data structures in more detail. Also, try to add a couple of words on why a data structures is cool (as Jonas Kölker already pointed out). Also, try to provide one data-structure per answer. This will allow the better data structures to float to the top based on their votes alone.

  Read the article

• The Definition of Regular Languages

  - by AraK

  Good Day, I have tried, and burned my brain to understand the definition of Regular Languages in Discrete Mathematics and its Applications(Rosen) without reaching the goal of understanding why the definition is like that in this book. On page(789), I am rephrasing the definition: Type 3 grammars are defined as: w1 --> w2 Where w1 is a non-terminal, and w2 is of the form: w2 = aB w2 = a Where B is a non-terminal, and a is a terminal. A special case is when w1 is the starting symbol and w2 is lambda(the empty string): w1 = S S --> lambda Two questions I couldn't find an answer for. First, Why can't w2 be of the form Ba. Second, Why lambda is only allowed for the starting symbol only. The book states that, regular languages are equivalent to Finite State Automaton, and we can easily see that a we can build FSA for both cases. I took a look at other resources, and these restrictions don't exist in these resources. Thanks,

  Read the article

• openss7 ss7 I_LINK ioctl

  - by deddihp

  Hello everyone, is there anyonve have used openss7 before ?. well, I am trying to implement MTP with mtpi interface. so i use I_LINK to link between M2PA and MTP. But I got some error, ioctl invalid argument. Do you have some suggestion for me ?. Thanks. your answer will be very helpful for me. int a1 = open("/dev/sctp_n", O_RDWR); int a2 = open("/dev/mtp", O_RDWR); ioctl(a1, I_PUSH, "m2pa-sl"); perror("m2pa-sl"); int a3 = ioctl(a1, I_LINK, a2); perror("ilink");

  Read the article

• Intermittent "No Database Selected" in PHP/MySQL?

  - by ANE

  Have a PHP/MySQL form with a dropdown box containing a list of 350 names. When any random name is selected, sometimes it works & displays info about that name from the database, and sometimes the form gives the error "No Database Selected". Here's what I've tried, pretty much grasping at straws as I'm not a programmer: Increasing max_connections in /etc/my.cnf from 200 to 2000 (even though only 4-5 connections are made and it's a lightly used server) Changing mysql_pconnect to mysql_connect Adding the word true to this connection string: $mysql = mysql_pconnect($hostname_mysql, $username_mysql, $password_mysql, true) or trigger_error(mysql_error(),E_USER_ERROR); Changing the word require_once to require on this line: [?php require('/home/user/Connections/mysql.php'); ?] Enabling MySQL & PHP query & error logging. (no errors logged) Here is the code: [removed old bad code] Update: Working answer from Rob Apodaca below.

  Read the article

• Caesar Cipher in Java (Spanish Characters)

  - by Rodolfo

  I've reading this question, and I was wondering if Is there any way to consider the whole range of characters? For example, "á", "é", "ö", "ñ", and not consider " " (the [Space])? (For example, my String is "Hello World", and the standard result is "Khoor#Zruog"; I want to erase that "#", so the result would be "KhoorZruog") I'm sure my answer is in this piece of code: if (c >= 32 && c <= 127) { // Change base to make life easier, and use an // int explicitly to avoid worrying... cast later int x = c - 32; x = (x + shift) % 96; chars[i] = (char) (x + 32); } But I've tried some things, and it didn't work.

  Read the article

• Application Server or Lightweight Container?

  - by Jeff Storey

  Let me preface this by saying this is not an actual situation of mine but I'm asking this question more for my own knowledge and to get other people's inputs here. I've used both Spring and EJB3/JBoss, and for the smaller types of applications I've built, Spring (+Tomcat when needed) has been much simpler to use. However, when scaling up to larger applications that require things like load balancing and clustering, is Spring still a viable solution? Or is it time to turn to a solution like EJB3/JBoss when you start to get big enough to need that? I'm not sure if I've scoped the problem well enough to get a good answer, so please let me know. Thanks, Jeff

  Read the article

• ssh-keygen accepting stdin

  - by Ryan

  I am trying to call ssh-keygen using a variable through bash as an input instead of a file to get a fingerprint of a public key. This method does not work as it says the key file is invalid (it's correct for sure) echo $pubkey | ssh-keygen -lf /dev/stdin This does work ssh-keygen -lf /dev/stdin < alpha.pub This does not work because I get an ambiguous redirect ssh-keygen -lf /dev/stdin < $(echo $pubkey) I would appreciate some insight as to how to get ssh-keygen to read from a variable with a public key and if possible, an explanation as to why the redirects aren't doing what I think they should be doing. I searched online but many of the redirect tutorials didn't seem to answer my questions.

  Read the article

• Call the method of base Class which was over ridden

  - by Abhijith Venkata

  I have illustrated my question in this example class Car { public void start(){ System.out.println("Car Started!!!"); } } class Mercedes extends Car { public void start(){ System.out.println("Mercedes Started!!!"); } } Now, in my main program, I write Mercedes m = new Mercedes(); m.start(); It prints: Mercedes Started!!! How do I call the start() method of Car class using the same object so that the output can be Car Started!!!. Edit: Actually It was asked in an interview I attended. I gave the super keyword answer. But the interviewer denied it. He said he'd give me a hint and said Virtual Function. I have no idea how to use that hint.

  Read the article

• Restore Emacs Session/Desktop

  - by Patrick McLaren

  I've been searching for how to restore an emacs session, with no luck. I'm looking to restore all previously open buffers, some of which might contain erc, shells, directory listings, files, etc. Every time I open emacs, I spend a considerable amount of time arranging my buffers; splitting them into rows and columns, opening a shell, arranging irc channels. It takes a while to get onto work. I've tried adding the following to my init.el (desktop-save-mode 1) And then using M-x desktop-save. This only seems to restore files that are open, not shells or anything else running within buffers. I've also checked the following questions (sorry, not able to post links yet): Session management in emacs using Desktop library Emacs session / projects / window management Emacs: reopen buffers from last session on startup? And read through: DeskTop and EmacsSession at emacswiki.org/emacs/SessionManagement Here's a screenshot example of my emacs session. A simple answer would be to just focus on real work :P

  Read the article

• How to programatically record the start and end of an MVC FileResult for logging of incomplete downl

  - by Richard

  Hi, I have been investigating how My ASP.NET MVC application can log unsuccessful / incomplete downloads. I have a controller handling the file requests which currently returns a FileResult. What I need to record is the IPAddress, filename and when the download started, then the same data and when it completed. I have looked at intercepting the request start and end with an HttpModule and also IIS7 failed request tracing but am not sure which route would be best and have this feeling that maybe I am missing an obvious answer to the problem. Does anyone have any suggestions or know of any alternatives as this seems like something many people would want to know from their web server? Thanks for your help

  Read the article

• What is everything involved from typing in code to executing a program?

  - by Befall

  I realized, when just asking a question, I don't understand all the components that are part of the coding process. This seems a silly question, but I can't find a definitive answer on Google, Wiki, nothing. What exactly are all the parts called, and how do they work and intertwine? I'm talking whatever you type code into, whatever checks that for errors, compiles it, and runs it. I'd appreciate any links, repeats, etc. I apologize for such a bland, stupid question.

  Read the article

• Meta Tags in Google Site Search

  - by ullmark

  Hi, I'm planning on implementing a google site search (and paying for it so I can get access to the XML). One thing I am wondering about is the possibility to use custom meta tags in it. I've heard yes from colleagues but nothing confirmed. Searching for an answer has given nothing (maybe because you cant?) Anybody knows? Edit: I want to be able to retrieve those meta tags from the search result to be able to provide different styling for different types of pages.

  Read the article

• how do i claim a low-numbered port as non-root the "right way"

  - by qbxk

  I have a script that I want to run as a daemon listening on a low-numbered port (< 1024) Script is in python, though answers in perl are also acceptable. The script is being daemonized using start-stop-daemon in a startup script, which may complicate the answer What I really (think) don't want is to type ps -few and see this process running with a "root" on it's line. How do I do it? ( from my less-than-fully-educated-about-system-calls perspective, I can see 3 avenues, Run the script as root (no --user/--group/--chuid to start-stop-daemon), and have it de-escalate it's user after it claims the port Setuid root on the script (chmod u+s), and run the script as the running user, (via --user/--group/--chuid to start-stop-daemon, the startup script still has to be called as root), in the script, acquire root privileges, claim the port, and then revert back to normal user something else i'm unaware of )

  Read the article

• Is selling a "website screen scraper" illegal?

  - by Yatendra Goel

  I have coded a "website screen scraper" and want to sell it commercially. I know that webpages scraped by the screen scraper are restricted to be scraped by the webmaser of that website. The robots.txt file of the website says that its webpages must not be scraped. So my question is whether selling that screen scraper is a crime or using that screen scraper is a crime in legal terms. I know that this question is related to law but I thought the software experts on SO must also have answer to this question.

  Read the article

• How can I use text from an EditText Field into a web page?

  - by S.M. Hasibur Rahman

  Hi there, I am creating a library search engine based on android. I want to have an EditText field in my application, where user will put the search text. And upon clicking the search button it should search using the library web page. I want to use the text being put in the EditText field to be used by the web page in the background and want to show the result to the user. Could find a clue. I will be really grateful if you could answer asap. Thanks. / Hasibur Rahman

  Read the article

• How to handle JPA annotations for a pointer to a generic interface

  - by HDave

  I have a generic class that is also a mapped super class that has a private field that holds a pointer to another object of the same type: @MappedSuperclass public abstract class MyClass<T extends MyIfc<T>> implements MyIfc<T> { @OneToOne() @JoinColumn(name = "previous", nullable = true) private T previous; ... } My problem is that Eclipse is showing an error in the file at the OneToOne "Target Entity "T" for previous is not an Entity." All of the implementations of MyIfc are, in fact, Entities. I should also add that each concrete implementation that inherit from MyClass uses a different value for T (because T is itself) so I can't use the "targetEntity" attribute. I guess if there is no answer then I'll have to move this JPA annotation to all the concrete subclasses of MyClass. It just seems like JPA/Hibernate should be smart enough to know it'll all work out at run-time. Makes me wonder if I should just ignore this error somehow.

  Read the article

• Use SQL to filter the results of a stored procedure

  - by Ben McCormack

  I've looked at other questions on Stack Overflow related to this question, but none of them seemed to answer this question clearly. We have a system Stored Procedure called sp_who2 which returns a result set of information for all running processes on the server. I want to filter the data returned by the stored procedure; conceptually, I might do it like so: SELECT * FROM sp_who2 WHERE login='bmccormack' That method, though, doesn't work. What are good practices for achieving the goal of querying the returned data of a stored procedure, preferably without having to look of the code of the original stored procedure and modify it.

  Read the article

• make desktop sms application using blackberry

  - by Amit Kumar Jha

  hey all, I have to make a SMS sending application in .NET, which uses the attached Blackberry handset(blackberry tour 9630 to be precise) to send SMS. I have never worked on smartphone application development, so want help in doing this. I searched SO for an answer and found one question, but its in java and i think that code would run on blackberry itself and not on desktop, correct me if i am wrong. So if someone could point me in the right direction I would be very grateful. Thanks in advance to all those who reply.

  Read the article

• handling Concurrency in SQL SERVER 2005

  - by sameer

  Hi, I have one question for you, if you can answer and refer resource it will be great help. I have a scenario where i need to create a appointment slot and a serial no for each slot memberwise. ex: Member Id |App Slot # 1|1 1|2 2|1 2|2 1|3 what im doing is take the Max slot number,increamenting it and insert it memberwise. but the problem is concurrent user can create a slot when i take the max slot after that if any other user insert the slot the value that im working with is no more valid, how to over come this problem Thanks & Regards, Sameer

  Read the article

• Using a JMS Session from different threads

  - by Evan

  From the javadoc for Session it states: A Session object is a single-threaded context for producing and consuming messages. So I understand that you shouldn't use a Session object from two different threads at the same time. What I'm unclear on is if you could use the Session object (or children such as a Queue) from a different thread than the one it created. In the case I'm working on, I'm considering putting my Session objects into a pool of available sessions that any thread could borrow from, use, and return to the pool when it is finished with it. Is this kosher? (Using ActiveMQ BTW, if that impacts the answer at all.)

  Read the article

• Counting problem: possible sudoko tables?

  - by Sorush Rabiee

  Hi, I'm working on a sudoko solver. my method is using a game tree and explore possible permutations for each set of digits by DFS Algorithm. in order to analyzing problem, i want to know what is the count of possible valid and invalid sudoko tables? - a 9*9 table that have 9 one, 9 two, ... , 9 nine. (this isn't exact duplicate by this question) my solution is: 1- First select 9 cells for 1s: (*) 2- and like (1) for other digits (each time, 9 cells will be deleted from remaining available cells): C(81-9,9) , C(81-9*2,9) .... = 3- finally multiply the result by 9! (permutation of 123456789 in (*)) this is not equal to accepted answer of this question but problems are equivalent. what did i do wrong?

  Read the article

• Whats the problem with int *p; *p=23;

  - by piemesons

  Yesterday in my interview I was asked this question. (At that time I was highly pressurized by so many abrupt questions). int *p; *p=23; printf('%d',*p); Is there any problem with this code? I explained him that you are trying to assign value to a pointer to whom memory is not allocated. But the way he reacted, it was like I am wrong. Although I got the job but after that he said Mohit think about this question again. I don't know what he was trying to say. Please let me know is there any problem in my answer?

  Read the article

• Convert args to flat list?

  - by Mark

  I know this is very similar to a few other questions, but I can't quite get this function to work correctly. def flatten(*args): return list(item for iterable in args for item in iterable) The output I'm looking for is: flatten(1) -> [1] flatten(1,[2]) -> [1, 2] flatten([1,[2]]) -> [1, 2] The current function, which I from another SO answer doesn't seem to produce correct results at all: >>> flatten([1,[2]]) [1, [2]] I wrote the following function which seems to work for 0 or 1 levels of nesting, but not deeper: def flatten(*args): output = [] for arg in args: if hasattr(arg, '__iter__'): output += arg else: output += [arg] return output

  Read the article

• Java paint speed relative to color model

  - by Jon

  I have a BufferedImage with an IndexColorModel. I need to paint that image onto the screen, but I've noticed that this is slow when using an IndexColorModel. However, if I run the BufferedImage through an identity affine transform it creates an image with a DirectColorModel and the painting is significantly faster. Here's the code I'm using AffineTransformOp identityOp = new AffineTransformOp(new AffineTransform(), AffineTransformOp.TYPE_BILINEAR); displayImage = identityOp.filter(displayImage, null); I have three questions 1. Why is painting the slower on an IndexColorModel? 2. Is there any way to speed up the painting of an IndexColorModel? 3. If the answer to 2. is no, is this the most efficient way to convert from an IndexColorModel to a DirectColorModel? I've noticed that this conversion is dependent on the size of the image, and I'd like to remove that dependency. Thanks for the help

  Read the article

• web developer editor ubuntu

  - by madphp

  Hi, I know theres hundred of questions and answers out there, but cant find one to specifically answer this. I need a web editor that will let me choose a dark themed editor. I understand gvim is one, but im not totally ready to let go of my mouse. I would like something like sublime text editor for windows, but open to other suggestions. The less bloat the best. I dont need a full IDE like eclipse, but willing to compromise, as long as the themes can easily be added. I've tried bluefish, kompozer and not happy with them. Just need a basic text editor that will highlight php syntax on a dark background.

  Read the article

< Previous Page | 416 417 418 419 420 421 422 423 424 425 426 427  | Next Page >