Search Results

Search found 30252 results on 1211 pages for 'network programming'.

Page 873/1211 | < Previous Page | 869 870 871 872 873 874 875 876 877 878 879 880  | Next Page >

• Reference variable to an object instantiated/initialized in another class in Java

  - by Alex

  The reason I'm asking is because I'm getting NullPointerException. I now this is very easy but I'm pretty new programming and find this a bit confusing. So say I have initialized an object in a class and want to access that same object from another class. Like now for instance I'm working on a small Chess game, in my model Game class I have an instance of Board, an object. Board, in turn, has an array of Squares. Square[][]. Game has board, board has Square[][]. Now if I want to access the Square[][] through the object board (in Game) of type Board. Do I just declare a variable with the same name and type or do I have to initialize it again? Board board OR Board board = new Board(); Note, I have already initialized board in the class Game so if I do it again, won't they be two totally different Board objects?

  Read the article

• python: find and replace numbers < 1 in text file

  - by hjp

  I'm pretty new to Python programming and would appreciate some help to a problem I have... Basically I have multiple text files which contain velocity values as such: 0.259515E+03 0.235095E+03 0.208262E+03 0.230223E+03 0.267333E+03 0.217889E+03 0.156233E+03 0.144876E+03 0.136187E+03 0.137865E+00 etc for many lines... What I need to do is convert all the values in the text file that are less than 1 (e.g. 0.137865E+00 above) to an arbitrary value of 0.100000E+01. While it seems pretty simple to replace specific values with the 'replace()' method and a while loop, how do you do this if you want to replace a range? thanks

  Read the article

• Expected symbol problems with this function declaration

  - by Derek

  I am just getting back into the C programming realm and I am having an issue that I think is linker related. I am using cmake for the first time as well, so that could be adding to my frustration. I have included a third party header file that contains a typedef that my code is trying to use, and it has this line: typedef struct a a_t so my code has a_t *var; //later..... var->member;// this line throws the error which throws the error: dereferencing pointer to incomplete type So am I just missing another include file, or is this a linker issue? I am building this code in QtCreator and using cmake. I can dive on a_t to see that typedef declaration in the included header, but I can't seem to dive on "struct a" itself to see where it's coming from. Thanks

  Read the article

• Keeping track of threads when creating them recursively

  - by 66replica

  I'm currently working on some code for my Programming Languages course. I can't post the code but I'm permitted to talk about some high level concepts that I'm struggling with and receive input on them. Basically the code is a recursive DFS on a undirected graph that I'm supposed to convert to a concurrent program. My professor already specified that I should create my threads in the recursive DFS method and then join them in another method. Basically, I'm having trouble thinking of how I should keep track of the threads I'm creating so I can join all of them in the other method. I'm thinking an array of Threads but I'm unsure how to add each new thread to the array or even if that's the right direction.

  Read the article

• Good real-world uses of metaclasses (e.g. in Python)

  - by Carles Barrobés

  I'm learning about metaclasses in Python. I think it is a very powerful technique, and I'm looking for good uses for them. I'd like some feedback of good useful real-world examples of using metaclasses. I'm not looking for example code on how to write a metaclass (there are plenty examples of useless metaclasses out there), but real examples where you have applied the technique and it was really the appropriate solution. The rule is: no theoretical possibilities, but metaclasses at work in a real application. I'll start with the one example I know: Django models, for declarative programming, where the base class Model uses a metaclass to fill the model objects of useful ORM functionality from the attribute definitions. Looking forward to your contributions.

  Read the article

• How compiling circular dependencies works?

  - by Fabio F.

  I've made the example in Java but I think (not tested) that it works in other (all?) languages. You have 2 files M.java that says public class MType{ XType x; MType(){ x = null;} } and another file XType.java (in the same directory) public class XType{ MType m; public XType(MType m){ this.m=m;} } Ok it's BAD programming , but.. if you run javac XType it compiles: compiles even MTypes because XType needs it. But.. MType needs XType.. how it works? How does the compiler know what is happening? Probably is a stupid question, but I would like to know how the compiler (javac or other compilers if you know.) manages that situation, not how to avoid it. I'm asking because i'm writing a precompiler and I would like to manage that situation.. Thank you

  Read the article

• the use of private keyword

  - by LAT

  Hi everyone I am new to programming. I am learning Java now, there is something I am not really sure, that the use of private. Why programmer set the variable as private then write , getter and setter to access it. Why not put everything in public since we use it anyway. public class BadOO { public int size; public int weight; ... } public class ExploitBadOO { public static void main (String [] args) { BadOO b = new BadOO(); b.size = -5; // Legal but bad!! } } I found some code like this, and i saw the comment legal but bad. I don't understand why, please explain me.

  Read the article

• Printing python tkinter output

  - by Eric

  I am trying to print the contents of a python tkinter canvas. I have tried using the postscript method of canvas to create a postscript file, but I get a blank page. I know this is because I have embedded widgets, and these do not get rendered by the postscript method. Before I rewrite my program to create a more printer-friendly layout, can someone suggest a way to approach this problem? All of the programming books I have ever read approach the problem of sending output to a printer with a bit of hand-waving, something along the lines of: "It's a difficult problem that depends on interacting with the operating system." I also have a hard time finding resources about this because of all the pages related to printing to the screen. I am using Python 2.6, on Ubuntu 9.04.

  Read the article

• Consolidating separate Loan, Purchase & Sales tables into one transaction table.

  - by Frank Computer

  INFORMIX-SE with ISQL 7.3: I have separate tables for Loan, Purchase & Sales transactions. Each tables rows are joined to their respective customer rows by: customer.id [serial] = loan.foreign_id [integer]; = purchase.foreign_id [integer]; = sale.foreign_id [integer]; I would like to consolidate the three tables into one table called "transaction", where a column "transaction.trx_type" [char(1)] {L=Loan, P=Purchase, S=Sale} identifies the transaction type. Is this a good idea or is it better to keep them in separate tables? Storage space is not a concern, I think it would be easier programming & user=wise to have all types of transactions under one table.

  Read the article

• How can I get the domain name for a user logged into a Mac via Active Directory

  - by Lawrence Johnston

  In my Cocoa app how can I get the current user's domain when they're logged in via Active Directory? I need to determine two things: 1. If the current user is logged on to an Active Directory domain (only need to handle Active Directory). 2. If 1, the domain of the user. I've found references to Directory Services and the Open Directory Programming Guide but the latter is 10.6 only (I must support 10.5+) and I could not find any examples for the former that gave me an idea of what I needed to do.

  Read the article

• Debugging ASP.NET in VS

  - by negligible

  A lot of what I'm doing at the moment is figuring out other peoples code and adding or adapting functions, so currently I am debugging more than I am writing code of my own. I'm still new to this, Junior Developer, and I am always finding new ways to improve what I am doing. For example I recently found This Guide which had some excellent tips, such as overriding the ToString() method in your classes so children are readable from their parents. So I am looking for any other tips or tricks to make my debugging more efficient, as I recognise it as a big part of programming, that you more experienced programmers may have picked up or found. Anything appreciated, I can read websites just fine so no need to explain it yourself if you have a good link!

  Read the article

• C++ corrupt my thinking, how to trust auto garbage collector?

  - by SnirD

  I use to program mainly with C/C++, that's make me dealing with pointers and memory management daily. This days I'm trying to develop using other tools, such as Java, Python and Ruby. The problem is that I keep thinking C++ style, I'm writing code as C++ usually written in almost every programming language, and the biggest problem is the memory management, I keep writing bad code using references in Java and just get as close as I can to the C++ style. So I need 2 thinks here, one is to trust the garbage collector, let's say by seeing benchmarks and proofs that it's realy working in Java, and know what I should never do in order to get my code the best way it can be. And the second think is knowing how to write other languages code. I mean I know what to do, I'm just never write the code as most Java or Python programmers usually do, are there any books for C++ programmers just to introduce me to the writing conventions? (by the way, forgive me for my English mistakes)

  Read the article

• How can I declare a pointer structure using {}?

  - by Y_Y

  This probably is one of the easiest question ever in C programming language... I have the following code: typedef struct node { int data; struct node * after; struct node * before; }node; struct node head = {10,&head,&head}; Is there a way I can make head to be *head [make it a pointer] and still have the availability to use '{ }' [{10,&head,&head}] to declare an instance of head and still leave it out in the global scope? For example: //not legal!!! struct node *head = {10,&head,&head};

  Read the article

• Is It Worth Using Bitwise Operators In Methods?

  - by user1626141

  I am very new to Java (and programming in general, my previous experience is with ActionScript 2.0 and some simple JavaScript), and I am working my way slowly and methodically through Java: A Beginner's Guide by Herbert Schildt. It is an incredible book. For one thing, I finally understand more-or-less what bitwise operators (which I first encountered in ActionScript 2.0) do, and that they are more efficient than other methods for certain sums. My question is, is it more efficient to use a method that uses, say, a shift right, to perform all your divisions/2 (or divisions/even) for you in a large program with many calculations (in this case, a sprawling RPG), or is it more efficient to simply use standard mathematical operations because the compiler will optimise it all for you? Or, am I asking the wrong question entirely?

  Read the article

• Magento quantity field doesn't work

  - by madmax

  Hi, i simply can't find a solution to my problem! The quantity field worked as it should. After a few months of programming on the whole shop, i wanted to test the quantity field and recognized that it doesn't function. I only can add one product to the cart although i typed “3” in the quantity field. I didn’t change anything in product/view.phtml and addtocart.phtml. Don't know where i have to search for this error. Maybe someone can give me a tip... greets max

  Read the article

• Aside from performance concerns, is Java still chosen over Groovy/JRuby etc.?

  - by yar

  [This is an empirical question about the state-of-the-art: I am NOT asking if Java is cooler or less cool than the dynamic languages that work in the JVM.] Aside from cases where performance is a main decision factor, do companies/developers still willingly chose Java over Groovy, JRuby or JPython? Personal Note: The reason I am asking is that, while I do some subset of my professional work in Ruby (not JRuby, for now), in my personal projects I use Java. While I have written non-trivial apps in Groovy, I prefer Java, but I wonder if I should just get over it and do everything in Groovy. I like Java because I feel that static typing saves me time and aids refactoring. (No, I am not familiar with Scala.) However, I feel that this very empirical, on-topic programming question may inform my decision.

  Read the article

• C++ code generation for repeted task

  - by sateesh

  Hi, I have something like below which will get repeated many times based on the function that get called for e.g acceptfunction() { inserter["quantity"] = sdd.getfloat(quantity); inserter["prodtype"] = sdd.getstring(prodtype); : : so on } Like accept above there are 20 more functions(reject,cancel etc) which will do the similar thing.But the parameteres they insert can differ based on function called. How can I automate this kind of code.So that I dont need to write new function from scratch.Basically what I need is if i provide parametres like ("quantity",prodtype) through some text file or xml, it should generate the required function with the input parametres. Is this task can be handled through C++ tempalte Meta programming or someother code generation tool will help me to do this?

  Read the article

• What is an instance of a field called?

  - by waxwing

  This might be an odd question, but it has actually caused me some headache. In Object oriented programming, there are accepted names for key concepts. In our model, we have classes with methods and fields. Now, going to the data world: An instance of a class is called an object. An instance of a field is called... what? A value? Isn't the term value a little broad for this? I have been offered "property" as well, but isn't property also part of the model and not the data? (This is not purely academic, I am actually coding these concepts.)

  Read the article

• What are the difference between Cygwin on windows and real UNIX environment

  - by Tarun

  Hi, I am a C/C++ developer. I have never done C++ programming on UNIX, I have done only on windows. I want to practice C++ on Unix. (Because all big companies ask C++ with Unix). I have a laptop on which i do not want to install any other OS (because i have installed very important software on it and i don't have setups) So, I searched and found CygWin which is Unix emulator for Windows. I am thinking to practice C++ on this. Please help me, how can I practice/learn in more close to the environment(Unix Environment) that is used in Big companies like IBM. What will be the difference between Unix and Cygwin?

  Read the article

• Is there a server side API for Team Foundaion Server

  - by Ralph Shillington

  It would seem there is precious little documentation on programming against a TFS 2010 instance. What bits I have found, have next to nothing in the case of documentation beyond barebones listing of client access classes and their members, most likely autogenerated from the code comments. As I'm interested in building a silverlight client against TFS, I will need access to server side API (ideally the silverlight app will talk to my server (mainly for work items) and my server will in turn talk to the TFS server for the goods. Where is the doumentation (if any) for this kind of TFS integration?

  Read the article

• How does lock(syncRoot) make sense on a static method?

  - by Rising Star

  The following code is excerpted from the (Windows Identity Foundation SDK) template that MS uses to create a new Security Token Service Web Site. public static CustomSecurityTokenServiceConfiguration Current { get { HttpApplicationState httpAppState = HttpContext.Current.Application; CustomSecurityTokenServiceConfiguration customConfiguration = httpAppState.Get( CustomSecurityTokenServiceConfigurationKey ) as CustomSecurityTokenServiceConfiguration; if ( customConfiguration == null ) { lock ( syncRoot ) { customConfiguration = httpAppState.Get( CustomSecurityTokenServiceConfigurationKey ) as CustomSecurityTokenServiceConfiguration; if ( customConfiguration == null ) { customConfiguration = new CustomSecurityTokenServiceConfiguration(); httpAppState.Add( CustomSecurityTokenServiceConfigurationKey, customConfiguration ); } } } return customConfiguration; } } I'm relatively new to multi-threaded programming. I assume that the reason for the lock statement is to make this code thread-safe in the event that two web requests arrive at the web site at the same time. However, I would have thought that using lock (syncRoot) would not make sense because syncRoot refers to the current instance that this method is operating on... but this is a static method? How does this make sense?

  Read the article

• Are `return` and `break` useless inside a Ruby block when used as a callback?

  - by Skilldrick

  In Rails, blocks can be used as callbacks, e.g.: class User < ActiveRecord::Base validates_presence_of :login, :email before_create {|user| user.name = user.login.capitalize if user.name.blank?} end When a block is used like this, is there any use for break and return? I'm asking because normally in a block, break will break out of the loop, and return will return from the enclosing method. But in a callback context, I can't get my head round what that means. The Ruby Programming Language suggests that return could cause a LocalJumpError but I haven't been able to reproduce this in a Rails callback. Edit: with the following code I'd expect a LocalJumpError, but all the return does is stop the rest of the callback executing. class User < ActiveRecord::Base validates_presence_of :login, :email before_create do |user| return user.name = user.login.capitalize end

  Read the article

• Need help with some C# Counting Code

  - by kaywai

  Hi, I'm trying to code a counter in Ninjatrader which uses C# as its programming language. I would like this counter to commence counting upon the completion of the first counter and once it commences counting to consider only the new condition when counting. So, the first counter commences when Close[0] < Close[4]. The second counter commences ONLY after the first counter has reached 9 and its condition for counting is Close[0] <= Low[2]. I don't know how to write the part of the code where the second counter commences counting and its counts are independent of the first counter reaching 9.

  Read the article

• Creating many native GUI frontends for a cross-platform application

  - by Hugh Young

  I've been away from GUI programming for quite some time so please pardon my ignorance. I would like to attempt the following: Write a Mac OSX app but still be able to port to Win/Linux (i.e. C++ core with Obj-C GUI) Avoid Qt/other toolkits on OSX (i.e. talk to Cocoa directly - I feel that many Qt apps I use stick out like sore thumbs compared to the rest of my system) Not as important, but it would be nice to avoid Visual Studio if it means I can have the freedom to use newer C++ features even on Windows if they help create better code. I believe this configuration might get me what I'm looking for: Core C++ Static Library OSX GUI (Cocoa) Windows GUI (Qt+MinGW?) OR (no new C++ features, Visual Studio + ManagedC++/C#/????) Linux GUI (Qt) Once again, sorry for my ignorance but is this possible? Is this sane? Are there any real-world open source examples accomplish something like this?

  Read the article

• work question how to start working as a programmer what do i need!

  - by giorgo

  Hi i am learning java and php i have some projects from uni.(Gui,s in java with mysql and a web application in php with mysql ++ more things like this.) i have started learning mvc struts spring and i also lerning php +zend +++++ more stuff etc....you can't learn everything!!!!!!!!!!!!!!!!!!!!!!! I would like to ask how can i find a job as a programmer-software eng because i have send my cv in many companys but all of them said me that i need work expirience. How All of you started your programming expirience. Did you make some projects and send them did you you have somebody that help you ...??? i am totaly alone i do everything by my self. can anyone answer this?everybody starts from somewhere but what if this somewhere don't come?what to do ?? how to start !!!!!!! Thanks

  Read the article

< Previous Page | 869 870 871 872 873 874 875 876 877 878 879 880  | Next Page >