Search Results

Search found 20211 results on 809 pages for 'language implementation'.

Page 680/809 | < Previous Page | 676 677 678 679 680 681 682 683 684 685 686 687  | Next Page >

• How does one implement storage/retrieval of smart-search/mailbox features?

  - by humble_coder

  Hi All, I have a question regarding implementation of smart-search features. For example, consider something like "smart mailboxes" in various email applications. Let's assume you have your data (emails) stored in a database and, depending on the field for which the query will be created, you present different options to the end user. At the moment let's assume the Subject, Verb, Object approach… For instance, say you have the following: SUBJECTs: message, to_address, from_address, subject, date_received VERBs: contains, does_not_contain, is_equal_to, greater_than, less_than OBJECTs: ??????? Now, in case it isn't clear, I want a table structure (although I'm not opposed to an external XMLesque file of some sort) to store (and later retrieve/present) my criteria for smart searches/mailboxes for later use. As an example, using SVO I could easily store then reconstruct a query for "date between two dates" -- simply use "date greater than" AND "date less than". However, what if, in the same smart search, I wanted a "between" OR'ed with another criterion? You can see that it might get out of hand -- not necessarily in the query creation (as that is rather simplistic), but in the option presentation and storage mechanism. Perhaps I need to think more on a more granular level. Perhaps I need to simply allow the user to select AND or OR for each entry independently instead of making it an ALL OR NOTHING type smart search (i.e. instead of MATCH ALL or MATCH ANY, I need to simply allow them to select -- I just don't want it to turn into a Hydra). Any input would be most appreciated. My apologies if the question is a bit incoherent. It is late, and I my brain is toast. Best.

  Read the article

• Connections hanging on read()

  - by viraptor

  Hi, Short version: I've got a strange issue with a server accepting TCP connections. Even though there are normally some processes waiting, at some volume of connections it hangs. Long version: The server is written in Perl and binds a $srv socket with the reuse flag and listen == 5. Afterwards, it forks into 10 processes with a loop of $clt=$srv->accept(); do_processing($clt); $clt->shutdown(2); The client written in C is also very simple - it sends some lines, then receives all lines available and does a shutdown(sockfd, 2); There's nothing async going on and at the end both send and receive queues are empty (as reported by netstat). Connections last only ~20ms. All clients behave the same way, are the same implementation, etc. Now let's say I'm accepting X connections from client 1 and another X from client 2. Processes still report that they're idle all the time. If I add another X connections from client 3, suddenly the server processes start hanging just after accepting. The first blocking thing they do after accept(); is while (<$clt>) ... - but they don't get any data (on the first try already). Suddenly all 10 processes are in this state and do not stop waiting. On strace, the server processes seem to hang on read(), which makes sense. There are loads of connections in TIME_WAIT state belonging to that server (~100 when the problem starts to manifest), but this might be a red herring. What could be happening here?

  Read the article

• Reversible numerical calculations in Prolog

  - by user8472

  While reading SICP I came across logic programming chapter 4.4. Then I started looking into the Prolog programming language and tried to understand some simple assignments in Prolog. I found that Prolog seems to have troubles with numerical calculations. Here is the computation of a factorial in standard Prolog: f(0, 1). f(A, B) :- A > 0, C is A-1, f(C, D), B is A*D. The issues I find is that I need to introduce two auxiliary variables (C and D), a new syntax (is) and that the problem is non-reversible (i.e., f(5,X) works as expected, but f(X,120) does not). Naively, I expect that at the very least C is A-1, f(C, D) above may be replaced by f(A-1,D), but even that does not work. My question is: Why do I need to do this extra "stuff" in numerical calculations but not in other queries? I do understand (and SICP is quite clear about it) that in general information on "what to do" is insufficient to answer the question of "how to do it". So the declarative knowledge in (at least some) math problems is insufficient to actually solve these problems. But that begs the next question: How does this extra "stuff" in Prolog help me to restrict the formulation to just those problems where "what to do" is sufficient to answer "how to do it"?

  Read the article

• how to send on users profile page on selecting username( using json autosuggest script)

  - by I Like PHP

  i m using auto suggest using Ajax Json . now when a user select a user name , i want to send user on the link of that user name my json data is coming in this way { query:'hel', suggestions:["hello world","hell boy ","bac to hell"], data:["2","26","34"] } now what i want that user goes to http://userProfile.php?uid=26 on select username(suppose user select "hell boy") how to do this?? UPDATE: i describe what i m doing step by step i m using a searchbox using jquery ajax, when user write some text on input box , we show (suggest) value regarading their search STEP 1. when user write atleast(2 letter) <input type="text" name="q" id="query" />then a function(below) in invoked in which i send the value written on text box(eg. hell). <script type="text/javascript" language="javascript"> var options, a; jQuery(function(){ options = { serviceUrl:'rpc.php' }; var a = $('#query').autocomplete({ serviceUrl:'rpc.php', minChars:3, delimiter: /(,|;)\s*/, // regex or character maxHeight:400, width:300, zIndex: 9999, deferRequestBy: 0, //miliseconds }); }); </script> STEP 3: on rpc.php, i collect the data and show using JSON my final data come in below format { query:'hell', suggestions:["hello world","hell boy ","bac to hell"], data:["2","26","34"] } where suggestion list having username and data is userid( from user_tables). above data comes in a div (on frontend) where user name displayed in a list STEP 4: now if i select any username using uparrow, downarrow then that name is filled in input box, STEP 5: now what i want that when user select usename then page automatically goes to that user's profile section ( userprofile.php?uid=2)

  Read the article

• Java ternary operator and boxing Integer/int?

  - by Markus

  I tripped across a really strange NullPointerException the other day caused by an unexpected type-cast in the ternary operator. Given this (useless exemplary) function: Integer getNumber() { return null; } I was expecting the following two code segments to be exactly identical after compilation: Integer number; if (condition) { number = getNumber(); } else { number = 0; } vs. Integer number = (condition) ? getNumber() : 0; . Turns out, if condition is true, the if-statement works fine, while the ternary opration in the second code segment throws a NullPointerException. It seems as though the ternary operation has decided to type-cast both choices to int before auto-boxing the result back into an Integer!?! In fact, if I explicitly cast the 0 to Integer, the exception goes away. In other words: Integer number = (condition) ? getNumber() : 0; is not the same as: Integer number = (condition) ? getNumber() : (Integer) 0; . So, it seems that there is a byte-code difference between the ternary operator and an equivalent if-else-statement (something I didn't expect). Which raises three questions: Why is there a difference? Is this a bug in the ternary implementation or is there a reason for the type cast? Given there is a difference, is the ternary operation more or less performant than an equivalent if-statement (I know, the difference can't be huge, but still)?

  Read the article

• C# Virtual method call in constructor - how to refactor?

  - by Cristi Diaconescu

  I have an abstract class for database-agnostic cursor actions. Derived from that, there are classes that implement the abstract methods for handling database-specific stuff. The problem is, the base class ctor needs to call an abstract method - when the ctor is called, it needs to initialize the database-specific cursor. I know why this shouldn't be done, I don't need that explanation! This is my first implementation, that obviously doesn't work - it's the textbook "wrong way" of doing it. The overridden method accesses a field from the derived class, which is not yet instantiated: public abstract class CursorReader { private readonly int m_rowCount; protected CursorReader() { m_rowCount = CreateCursor(sqlCmd); //virtual call ! } protected abstract int CreateCursor(string sqlCmd); } public class SqlCursorReader : CursorReader { private SqlConnection m_sqlConnection; public SqlCursorReader(string sqlCmd, SqlConnection sqlConnection) { m_sqlConnection = sqlConnection; //field initialized here } protected override int CreateCursor(string sqlCmd) { //uses not-yet-initialized member *m_sqlConnection* //so this throws a NullReferenceException var cursor = new CustomCursor(sqlCmd, m_sqlConnection); return cursor.Count(); } } I will follow up with an answer on my attempts to fix this...

  Read the article

• Why does this program take up so much memory?

  - by Adrian

  I am learning Objective-C. I am trying to release all of the memory that I use. So, I wrote a program to test if I am doing it right: #import <Foundation/Foundation.h> #define DEFAULT_NAME @"Unknown" @interface Person : NSObject { NSString *name; } @property (copy) NSString * name; @end @implementation Person @synthesize name; - (void) dealloc { [name release]; [super dealloc]; } - (id) init { if (self = [super init]) { name = DEFAULT_NAME; } return self; } @end int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; Person *person = [[Person alloc] init]; NSString *str; int i; for (i = 0; i < 1e9; i++) { str = [NSString stringWithCString: "Name" encoding: NSUTF8StringEncoding]; person.name = str; [str release]; } [person release]; [pool drain]; return 0; } I am using a mac with snow leopard. To test how much memory this is using, I open Activity Monitor at the same time that it is running. After a couple of seconds, it is using gigabytes of memory. What can I do to make it not use so much?

  Read the article

• Solr/Lucene Scorer

  - by TFor

  We are currently working on a proof-of-concept for a client using Solr and have been able to configure all the features they want except the scoring. Problem is that they want scores that make results fall in buckets: Bucket 1: exact match on category (score = 4) Bucket 2: exact match on name (score = 3) Bucket 3: partial match on category (score = 2) Bucket 4: partial match on name (score = 1) First thing we did was develop a custom similarity class that would return the correct score depending on the field and an exact or partial match. The only problem now is that when a document matches on both the category and name the scores are added together. Example: searching for "restaurant" returns documents in the category restaurant that also have the word restaurant in their name and thus get a score of 5 (4+1) but they should only get 4. I assume for this to work we would need to develop a custom Scorer class but we have no clue on how to incorporate this in Solr. Another option is to create a custom SortField implementation similar to the RandomSortField already present in Solr. Maybe there is even a simpler solution that we don't know about. All suggestions welcome!

  Read the article

• Does/Will autofac's ASP.NET integration support PreInit or Init events?

  - by David Rubin

  I see from poking around in the 1.4.4 source that Autofac's ASP.NET integration (via Autofac.Integration.Web) peforms injection of properties on the Page as part of the HttpContext.PreRequestHandlerExecute event handling, but that the page's child controls don't get their properties injected until Page.PreLoad. What this means, though is that the injected properties of child controls are unavailable for use in the OnInit event handler. For example, this works fine: HelloWorld.aspx: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="HelloWorld.aspx.cs" Inherits="HelloWorld" %> <html> <body> <asp:Label runat="server" id="lblMsg" OnInit="HandleInit"/> </body> </html> HelloWorld.aspx.cs: ... protected void HandleInit() { lblMsg.Text = _msgProvider.GetMessage(); } public IMsgProvider _msgProvider { private get; set; } // <-- Injected But changing the HelloWorld Page to a UserControl (.acsx) and putting the UserControl in another page doesn't work because _msgProvider isn't injected early enough. Is there a way to make Autofac inject properties of child controls earlier? Or is this something that can be addressed in a future build? Thanks!

  Read the article

• How do I attach a link (to a View) to an image in ASP.NET MVC?

  - by Ryan Pitts

  Ok, so here is my situation. I am creating a web application using ASP.NET MVC 2 using the C# language. I have programmed in HTML, CSS, and PHP for several years and I am very new to ASP.NET. The part that I am having trouble with is the image gallery. The setup: I have a link on the navigation bar that goes to a "Galleries" page. This page will show a list of galleries. Each gallery has a title, an image, and a description. All of this information is pulled from an XML file. I'm using the XML file like a database. I wanted to use this method so that i could easily update the list of galleries and have the updated XML file automatically be reflected by the website. Now, the galleries should link to an "Images" page. This page will display a list of images within the gallery based on what gallery was selected. This page will also pull from an XML file. The problem: I cannot seem to attach a dynamic link to the image? I am also stuck and not sure how to get the correct View to display. I know I need to do something with the controllers and models, right? I have some code if needed? I would greatly appreciate any help or direction for this! Thanks!

  Read the article

• Indexing and Searching Over Word Level Annotation Layers in Lucene

  - by dmcer

  I have a data set with multiple layers of annotation over the underlying text, such as part-of-tags, chunks from a shallow parser, name entities, and others from various natural language processing (NLP) tools. For a sentence like The man went to the store, the annotations might look like: Word POS Chunk NER ==== === ===== ======== The DT NP Person man NN NP Person went VBD VP - to TO PP - the DT NP Location store NN NP Location I'd like to index a bunch of documents with annotations like these using Lucene and then perform searches across the different layers. An example of a simple query would be to retrieve all documents where Washington is tagged as a person. While I'm not absolutely committed to the notation, syntactically end-users might enter the query as follows: Query: Word=Washington,NER=Person I'd also like to do more complex queries involving the sequential order of annotations across different layers, e.g. find all the documents where there's a word tagged person followed by the words arrived at followed by a word tagged location. Such a query might look like: Query: "NER=Person Word=arrived Word=at NER=Location" What's a good way to go about approaching this with Lucene? Is there anyway to index and search over document fields that contain structured tokens?

  Read the article

• Getting Preferred, Varied Products -- Tough Pseudocode Question

  - by Volomike

  I have a Dallas client who has given me a tough process to work out. I'm seeking your advice. I use PHP, but the language doesn't matter. We can work this out in pseudocode. In a nutshell, this involves showing products on a page based on matching keyword phrases, and using a preferred product provider, but varying this up so that I try to show products from each provider as much as possible when I can. He has 3 product companies: Amazon, eBay, and Overstock. I already have worked out with the API to get products back in an array via a function. He wants to give the user the preference of which one to use primarily -- so a priority number on each. He wants to display anywhere from 1 to 6 products on a page from them. Let's go with 6 for now in this example to start with. Let's assume Amazon first, then eBay, then Overstock as far as priority. He wants me to attempt to take a keyword phrase and find relevant products (all the keywords found in product title) from Amazon, eBay, and Overstock. If we find 1 product from each provider, he wants me to only display one product from each. But if we run out of a particular provider with a matching product, I start over again and grab another product from another provider until we reach 6 products. If there just aren't 6 relevant products, then I do the best I can -- even if I only display one product. If no relevant products, then I don't display anything.

  Read the article

• Circular dependency with generics

  - by devoured elysium

  I have defined the following interface: public interface IStateSpace<State, Action> where State : IState where Action : IAction<State, Action> // <-- this is the line that bothers me { void SetValueAt(State state, Action action); Action GetValueAt(State state); } Basically, an IStateSpace interface should be something like a chess board, and in each position of the chess board you have a set of possible movements to do. Those movements here are called IActions. I have defined this interface this way so I can accommodate for different implementations: I can then define concrete classes that implement 2D matrix, 3D matrix, graphs, etc. public interface IAction<State, Action> { IStateSpace<State, Action> StateSpace { get; } } An IAction, would be to move up(this is, if in (2, 2) move to (2, 1)), move down, etc. Now, I'll want that each action has access to a StateSpace so it can do some checking logic. Is this implementation correct? Or is this a bad case of a circular dependence? If yes, how to accomplish "the same" in a different way? Thanks

  Read the article

• Chinese records of sqlite databse are in not accessable in iphone app

  - by Mas

  Hi! I'm creating an iphone app. In which I'm reading data from the sqlite db and presenting it in the tableview control. Problem is that the data is in chinese language. Due to unknown reason, when I read/fetch record from the sqlite table, some records are presented and other are missed by objc. Even objc reads some columns of the missing values, But returns the nil results of the some columns. In reality these columns are not empty. I tried many solutions but didn't find any suitable. Same database is working perfectly in the android version of the app. Any one can help here is the code of reading the chinese records from table Quote *q = [[Quote alloc] init]; q.catId = sqlite3_column_int(statement, 0); q.subCatId = sqlite3_column_int(statement, 1); q.quote = [NSString stringWithUTF8String:(char *)sqlite3_column_text(statement, 2)]; and here is the some records which iphone misses ??????·??? ??????,????????! ??????,??????? Thanks

  Read the article

• Recursive QuickSort suffering a StackOverflowException -- Need fresh eyes

  - by jon

  I am working on a Recursive QuickSort method implementation in a GenericList Class. I will have a second method that accepts a compareDelegate to compare different types, but for development purposes I'm sorting a GenericList<int I am recieving stackoverflow areas in different places depending on the list size. I've been staring at and tracing through this code for hours and probably just need a fresh pair of (more experienced)eyes. Definitely wanting to learn why it is broken, not just how to fix it. public void QuickSort() { int i, j, lowPos, highPos, pivot; GenericList<T> leftList = new GenericList<T>(); GenericList<T> rightList = new GenericList<T>(); GenericList<T> tempList = new GenericList<T>(); lowPos = 1; highPos = this.Count; if (lowPos < highPos) { pivot = (lowPos + highPos) / 2; for (i = 1; i <= highPos; i++) { if (this[i].CompareTo(this[pivot]) <= 0) leftList.Add(this[i]); else rightList.Add(this[i]); } leftList.QuickSort(); rightList.QuickSort(); for(i=1;i<=leftList.Count;i++) tempList.Add(leftList[i]); for(i=1;i<=rightList.Count;i++) tempList.Add(rightList[i]); this.items = tempList.items; this.count = tempList.count; } }

  Read the article

• How to easily map c++ enums to strings

  - by Roddy

  I have a bunch of enum types in some library header files that I'm using, and I want to have a way of converting enum values to user strings - and vice-versa. RTTI won't do it for me, because the 'user strings' need to be a bit more readable than the enumerations. A brute force solution would be a bunch of functions like this, but I feel that's a bit too C-like. enum MyEnum {VAL1, VAL2,VAL3}; String getStringFromEnum(MyEnum e) { switch e { case VAL1: return "Value 1"; case VAL2: return "Value 2"; case VAL1: return "Value 3"; default: throw Exception("Bad MyEnum"); } } I have a gut feeling that there's an elegant solution using templates, but I can't quite get my head round it yet. UPDATE: Thanks for suggestions - I should have made clear that the enums are defined in a third-party library header, so I don't want to have to change the definition of them. My gut feeling now is to avoid templates and do something like this: char * MyGetValue(int v, char *tmp); // implementation is trivial #define ENUM_MAP(type, strings) char * getStringValue(const type &T) \ { \ return MyGetValue((int)T, strings); \ } ; enum eee {AA,BB,CC}; - exists in library header file ; enum fff {DD,GG,HH}; ENUM_MAP(eee,"AA|BB|CC") ENUM_MAP(fff,"DD|GG|HH") // To use... eee e; fff f; std::cout<< getStringValue(e); std::cout<< getStringValue(f);

  Read the article

• Endianness and C API's: Specifically OpenSSL.

  - by Hassan Syed

  I have an algorithm that uses the following OpenSSL calls: HMAC_update() / HMAC_final() // ripe160 EVP_CipherUpdate() / EVP_CipherFinal() // cbc_blowfish These algorithm take a unsigned char * into the "plain text". My input data is comes from a C++ std::string::c_str() which originate from a protocol buffer object as a encoded UTF-8 string. UTF-8 strings are meant to be endian neutrial. However I'm a bit paranoid about how OpenSSL may perform operations on the data. My understanding is that encryption algorithms work on 8-bit blocks of data, and if a unsigned char * is used for pointer arithmetic when the operations are performed the algorithms should be endian neutral and I do not need to worry about anything. My uncertainty is compounded by the fact that I am working on a little-endian machine and have never done any real cross-architecture programming. My beliefs/reasoning are/is based on the following two properties std::string (not wstring) internally uses a 8-bit ptr and a the resulting c_str() ptr will itterate the same way regardless of the CPU architecture. Encryption algorithms are either by design, or by implementation, endian neutral. I know the best way to get a definitive answer is to use QEMU and do some cross-platform unit tests (which I plan to do). My question is a request for comments on my reasoning, and perhaps will assist other programmers when faced with similar problems.

  Read the article

• What should be taught in a "Fundamentals of programming" course at university?

  - by Dervin Thunk

  I have started a new question (see here), because I think the topic is of importance in a more general form. The question is now: If you were a professor at a Computer Science Dept. in some university, what would make it into your course? This is a programming course, second term, first year computer science/computer engineering. Remember you have a limited amount of time, and students are of different levels of competence, and some may be scientists, but some will also go on to be programmers in companies of different kinds. You have to cater to all. Bonus: What language? (Although see this question for my current thoughts about this...) Maybe you want to attach a course outline from some university? See here for an even more general question about this. Answer: I can't really summarize this post... I guess it was too subjective. However, it looks like we have to cover the history of computing up to a certain extent, computer architecture (memory, registers, whatever), C, and finally some basic algos and data structures in a problem solving fashion. This will be the bare bones of the course. Thanks all. I will accept the most voted up answer to close the thread, as it should be done.

  Read the article

• Problem with writing mobilesubstrate plugins for iOS

  - by overboming

  I am trying to hooking message sending for iOS 3.2, I implement my own hook on a working ExampleHook program I find on the web. But my hook apparently caused segmentation fault everytime it hooks and I don't know why. I want to hook to [NSURL initWithString:(NSString *)URLString relativeToURL:(NSURL *)baseURL; and here is my related implementation static id __$GFWInterceptor_NSURL_initWithString2(NSURL<GFWInterceptor> *_NSURL, NSString *URLString, NSURL* baseURL){ NSLog(@"We have intercepted this url: %@",URLString); [_NSURL __HelloNSURL_initWithString:URLString relativeToURL:baseURL]; establish hook Class _$NSURL = objc_getClass("NSURL"); MSHookMessage(_$NSURL, @selector(initWithString:relativeToURL:), (IMP) &__$GFWInterceptor_NSURL_initWithString2, "__HelloNSURL_"); original method declaration - (void)__HelloNSURL_initWithString:(NSString *)URLString relativeToURL:(NSURL *)baseURL; and here is my gdb backtrace Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x74696e71 0x335625f8 in objc_msgSend () (gdb) bt 0 0x335625f8 in objc_msgSend () 1 0x32c05b1a in CFStringGetLength () 2 0x32c108a8 in _CFStringIsLegalURLString () 3 0x32b1c32a in -[NSURL initWithString:relativeToURL:] () 4 0x000877c0 in __$GFWInterceptor_NSURL_initWithString2 () 5 0x32b1c220 in +[NSURL URLWithString:relativeToURL:] () 6 0x32b1c1f4 in +[NSURL URLWithString:] () 7 0x3061c614 in createUniqueWebDataURL () 8 0x3061c212 in +[WebFrame(WebInternal) _createMainFrameWithSimpleHTMLDocumentWithPage:frameView:withStyle:editable:] () and apparently it hooks, but there is some memory issue there and I can't find anything to blame now

  Read the article

• OOP, Interface Design and Encapsulation

  - by Mau

  C# project, but it could be applied to any OO languages. 3 interfaces interacting: public interface IPublicData {} public /* internal */ interface IInternalDataProducer { string GetData(); } public interface IPublicWorker { IPublicData DoWork(); IInternalDataProducer GetInternalProducer(); } public class Engine { Engine(IPublicWorker worker) {} IPublicData Run() { DoSomethingWith(worker.GetInternalProducer().GetData()); return worker.DoWork(); } } Clearly Engine is parametric in the actual worker that does the job. A further source of parametrization is how we produce the 'internal data' via IInternalDataProducer. This implementation requires IInternalDataProducer to be public because it's part of the declaration of the public interface IPublicWorker. However, I'd like it to be internal since it's only used by the engine. A solution is make the IPublicWorker produce the internal data itself, but that's not very elegant since there's only a couple of ways of producing it (while there are many more worker implementations), therefore it's nice to delegate to a couple of separate concrete classes. Moreover, the IInternalDataProducer is used in more places inside the engine, so it's good for the engine to pass around the actual object. I'm looking for elegant ideas/patterns. Cheers :-)

  Read the article

• Problem with Boost::Asio for C++

  - by Martin Lauridsen

  Hi there, For my bachelors thesis, I am implementing a distributed version of an algorithm for factoring large integers (finding the prime factorisation). This has applications in e.g. security of the RSA cryptosystem. My vision is, that clients (linux or windows) will download an application and compute some numbers (these are independant, thus suited for parallelization). The numbers (not found very often), will be sent to a master server, to collect these numbers. Once enough numbers have been collected by the master server, it will do the rest of the computation, which cannot be easily parallelized. Anyhow, to the technicalities. I was thinking to use Boost::Asio to do a socket client/server implementation, for the clients communication with the master server. Since I want to compile for both linux and windows, I thought windows would be as good a place to start as any. So I downloaded the Boost library and compiled it, as it said on the Boost Getting Started page: bootstrap .\bjam It all compiled just fine. Then I try to compile one of the tutorial examples, client.cpp, from Asio, found (here.. edit: cant post link because of restrictions). I am using the Visual C++ compiler from Microsoft Visual Studio 2008, like this: cl /EHsc /I D:\Downloads\boost_1_42_0 client.cpp But I get this error: /out:client.exe client.obj LINK : fatal error LNK1104: cannot open file 'libboost_system-vc90-mt-s-1_42.lib' Anyone have any idea what could be wrong, or how I could move forward? I have been trying pretty much all week, to get a simple client/server socket program for c++ working, but with no luck. Serious frustration kicking in. Thank you in advance.

  Read the article

• Help me write my LISP :) LISP environments, Ruby Hashes...

  - by MikeC8

  I'm implementing a rudimentary version of LISP in Ruby just in order to familiarize myself with some concepts. I'm basing my implementation off of Peter Norvig's Lispy (http://norvig.com/lispy.html). There's something I'm missing here though, and I'd appreciate some help... He subclasses Python's dict as follows: class Env(dict): "An environment: a dict of {'var':val} pairs, with an outer Env." def __init__(self, parms=(), args=(), outer=None): self.update(zip(parms,args)) self.outer = outer def find(self, var): "Find the innermost Env where var appears." return self if var in self else self.outer.find(var) He then goes on to explain why he does this rather than just using a dict. However, for some reason, his explanation keeps passing in through my eyes and out through the back of my head. Why not use a dict, and then inside the eval function, when a new "sub-environment" needs to be created, just take the existing dict and update the key/value pairs that need to be updated, and pass that new dict into the next eval? Won't the Python interpreter keep track of the previous "outer" envs? And won't the nature of the recursion ensure that the values are pulled out from "inner" to "outer"? I'm using Ruby, and I tried to implement things this way. Something's not working though, and it might be because of this, or perhaps not. Here's my eval function, env being a regular Hash: def eval(x, env = $global_env) ........ elsif x[0] == "lambda" then ->(*args) { eval(x[2], env.merge(Hash[*x[1].zip(args).flatten(1)])) } ........ end The line that matters of course is the "lambda" one. If there is a difference, what's importantly different between what I'm doing here and what Norvig did with his Env class? If there's no difference, then perhaps someone can enlighten me as to why Norvig uses the Env class. Thanks :)

  Read the article

• How to develop Online Shopping Portal Application using PHP ?

  - by Sarang

  I do not know PHP & I have to develop a Shopping Portal with following Definition : Scenario: Online Shopping Portal XYZ.com wants to create an online shopping portal for managing its registered customers and their shopping. The customers need to register themselves first before they do shopping using the shopping portal. However, everyone, whether registered or not, can view the various products along with the prices listed in the portal. The registered customers, after logging in, are allowed to place order for one or more products from the products listed in the portal. Once the order is placed, the customer gets a reference order number and the order status should be “order in process”. The customers can track their order using the given reference number. The management of XYZ.com should be able to modify the order status of a particular reference order number to “shipped” once the products are shipped to the shipping address entered by the customer at the time of placing the order. The Functionalities required are : Create the interface for the XYZ.com shopping portal using HTML/XHTML and CSS. Implement the client side validations using JavaScript. Create the tables using MySQL. Implement the functionality using the server side scripting language, PHP. Integrate all the above tasks and make the XYZ.com shopping portal functional. How do I develop this application with following proper steps of development ?

  Read the article

• What is the minimal licensable source code?

  - by Hernán Eche

  Let's suppose I want to "protect" this code about being used without attribution, patenting it, or through any open source licence... #include<stdio.h> int main (void) { int version=2; printf("\r\n.Hello world, ver:(%d).", version); return 0; } It's a little obvious or just a language definition example.. When a source stop being "trivial, banal, commonplace, obvious", and start to be something that you may claim "rights"? Perhaps it depends on who read it, something that could be great geniality for someone that have never programmed, could be just obvious for an expert. It's easy when watching two sources there are 10000 same lines of code, that's a theft.. but that's not always so obvious. How to measure amount of "ownness", it's about creativity? line numbers? complexity? I can't imagine objetive answers for that, only some patches. For example perhaps the complexity, It's not fair to replace "years of engeneering" with "copy and paste". But is there any objetive index for objetive determination of this subject? (In a funny way I imagine this criterion: If the licence is longer than the code, then there is no owner, just to punish not caring storage space and world resources =P)

  Read the article

• How do I optimize this postfix expression tree for speed?

  - by Peter Stewart

  Thanks to the help I received in this post: I have a nice, concise recursive function to traverse a tree in postfix order: deque <char*> d; void Node::postfix() { if (left != __nullptr) { left->postfix(); } if (right != __nullptr) { right->postfix(); } d.push_front(cargo); return; }; This is an expression tree. The branch nodes are operators randomly selected from an array, and the leaf nodes are values or the variable 'x', also randomly selected from an array. char *values[10]={"1.0","2.0","3.0","4.0","5.0","6.0","7.0","8.0","9.0","x"}; char *ops[4]={"+","-","*","/"}; As this will be called billions of times during a run of the genetic algorithm of which it is a part, I'd like to optimize it for speed. I have a number of questions on this topic which I will ask in separate postings. The first is: how can I get access to each 'cargo' as it is found. That is: instead of pushing 'cargo' onto a deque, and then processing the deque to get the value, I'd like to start processing it right away. I don't yet know about parallel processing in c++, but this would ideally be done concurrently on two different processors. In python, I'd make the function a generator and access succeeding 'cargo's using .next(). But I'm using c++ to speed up the python implementation. I'm thinking that this kind of tree has been around for a long time, and somebody has probably optimized it already. Any Ideas? Thanks

  Read the article

< Previous Page | 676 677 678 679 680 681 682 683 684 685 686 687  | Next Page >