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  • i need help to designe code in c++

    - by user344987
    ) Design and implement a Graph data structure. Use adjacency matrix to implement the unweighted graph edges. The Graph must support the following operations: 1.Constructor 2.Destructor 3.Copy constructor 4.A function to add an edge between two nodes in the graph 5.A display function that outputs all the edges of the graph 6.A function edge that accepts two nodes, the function returns true if there is an edge between the passed nodes, and returns false otherwise. B.(100 points) Depth first search and Breadth first search functions. C.(100 points) A function to output a spanning tree of the graph, use any algorithm you find appropriate, also, make the necessary changes on the data structure in A to implement your algorithm.

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  • How could my code compliled correctly without necessary headers?

    - by ZhengZhiren
    I use the functions fork(),exec()... But how can this program compiled without including some extra headers(like sys/types.h, sys/wait.h). I use ubuntu 10.04 with gcc version 4.4.3 #include <stdio.h> #include <stdlib.h> int main() { pid_t pid; printf("before fork\n"); pid = fork(); if(pid == 0) { /*child*/ if(execvp("./cpuid", NULL)) { printf("error\n"); exit(0); } } else { if(wait(NULL) != -1) { printf("ok\n"); } } return 0; }

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  • Does the Internet make us less good programmers? [closed]

    - by stagas
    With all the information and code available nowadays on the Internet has that diminished our capability of remembering or learning stuff just because we know they're available somewhere out there, just a Google away or a StackOverflow question away? For example I find myself visiting php.net quite often to check the syntax of the same functions over and over again, not because my memory sucks, but I don't feel like keeping the information in me, since I know I'll find it again on the net. And about StackOverflow, isn't the process of figuring things out on your own supposed to improve your programming skills? If the answers are all just clicks away, do we actually learn something or just keep a pointer in our heads where to search for it again when we need it? Your thoughts are welcome. Hope it doesn't shut down as subjective or anything, the answers would be really interesting ;)

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  • Software Engineering Component Repository Tool

    - by user320480
    Hello, I'm working as a software engineer for a company. We are going to apply some software engineering standards in our development process. We need a tool which provides a repository for our peripheral products (functions, classes, libraries, ...) which is created during software development process for later use. The tool should provide some functionalities (e.g Name of the component, it's functionality, withing which projects it is used?, author, publication date, list of known bugs, user rating, comment, ...) and it's better to have a web-based interface. Does anybody know such a software?

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  • Possible to exclude or reorder a column from `*` ?

    - by Earlz
    Is it possible to exclude a column from a select * from table statement with SQL Server? I have a need for this and this is my only option other than parsing a raw SQL string to get out the required field names (I really don't want to do that). Just to be bold. When the query is made I do not have access to the list of fields needed from the table but I do know which field I do not need. This is part of a complex multi-part query. Surely there must be some way even if it's "hackish" such as using table variables or views My other option is to reorder the columns. My problem is with ExecuteScalar SQL functions which get the first row and first column.

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  • Function to set an auth_token

    - by john mossel
    In my form I have a hidden field: <input type="hidden" name="auth_token" value="<?php echo $auth_token; ?>"> This value is also stored in a session and a variable: $_SESSION['auth_token'] = hash('sha256', rand() . time() . $_SERVER['HTTP_USER_AGENT']); # TODO: put this in a function $auth_token = $_SESSION['auth_token']; When the form is submitted the two values are compared. It's a basic form token. Should this be made into two functions or just one when refactored? set_form_token() and get_form_token(), get_form_token() returning the session value, then I can compare it in my main code. What is the proper way of doing this?

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  • C++ Vector at/[] operator speed

    - by sub
    In order to give functions the option to modify the vector I can't do curr = myvec.at( i ); doThis( curr ); doThat( curr ); doStuffWith( curr ); But I have to do: doThis( myvec.at( i ) ); doThat( myvec.at( i ) ); doStuffWith( myvec.at( i ) ); (as the answers of my other question pointed out) I'm going to make a hell lot of calls to myvec.at() then. How fast is it, compared to the first example using a variable to store the result? Is there a different option for me? Can I somehow use pointers? When it's getting serious there will be thousands of calls to myvec.at() per second. So every little performance-eater is important.

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  • Java ServerSocketChannel SocketChannel (Callback)

    - by ikurtz
    I am trying to learn Java. I would like to implement a simple networked connect 4 game as well as a chat feature. I want my network logic to be non blocking so after much study I found that SocketChannel is what I am after regrading my needs. What has not made sense still is the lack of CallBack functions in SocketChannels.. Like one finds in C#. My query for this time is: How do I deliver the data received to the Chat or Game form (JFrame)? Some guidance is most welcome.

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  • Is pthread_spin_trylock safe inside of sigsegv handler of multithreaded application?

    - by TWMouton
    I am trying to implement a handler that on SIGSEGV will collect some information such as process-id, thread-id and a backtrace and write this information to a file/pipe/socket. The problem lies in that there is the (probably pretty high) possibility that if one thread experienced a SIGSEGV that the others will shortly follow. If two threads happen to make it to the bit of code where they're writing their report out at the same time then they'll interleave their writing (to the same file). I know that I should only be using async-signal-safe functions as detailed in signal(7) I also have seen at least two cases here and video linked in top answer here where others have used pthread_spin_trylock to get around this problem. Is this a safe way to prevent the above problem?

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  • Thread help with Android game

    - by Ciph3rzer0
    I need some help dealing with three Threads in Android One thread is the main thread, the other is the GLThread, and the other is a WorkerThread I created to update the game state. The problem I have is they all need to access the same LinkedList of game objects. Both the GLThread and my WorkerThread only read from the LinkedList, so no problem there, but occasionally I have the main thread adding in another game object to the list. How can I manage this? I tried using synchronized in front of the functions involved but it really slows down the application. For some reason, just catching the errors and not rendering or updating the game state that frame, causes it to start lagging permanently. Anyone have any great ideas?

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  • How to access constant defined in child class?

    - by kavoir.com
    I saw this example from php.net: <?php class MyClass { const MY_CONST = "yonder"; public function __construct() { $c = get_class( $this ); echo $c::MY_CONST; } } class ChildClass extends MyClass { const MY_CONST = "bar"; } $x = new ChildClass(); // prints 'bar' $y = new MyClass(); // prints 'yonder' ?> But $c::MY_CONST is only recognized in version 5.3.0 or later. The class I'm writing may be distributed a lot. Basically, I have defined a constant in ChildClass and one of the functions in MyClass (father class) needs to use the constant. Any idea?

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  • get foreign key objects in a single query - Django

    - by John
    Hi I have 2 models in my django code: class ModelA(models.Model): name = models.CharField(max_length=255) description = models.CharField(max_length=255) created_by = models.ForeignKey(User) class ModelB(models.Model): category = models.CharField(max_length=255) modela_link = models.ForeignKey(ModelA, 'modelb_link') functions = models.CharField(max_length=255) created_by = models.ForeignKey(User) Say ModelA has 100 records, all of which may or may not have links to ModelB Now say I want to get a list of every ModelA record along with the data from ModelB I would do: list_a = ModelA.objects.all() Then to get the data for ModelB I would have to do for i in list_a: i.additional_data = i.modelb_link.all() However this runs a query on every instance of i. Thus making 101 queries to run. Is there any way of running this all in just 1 query. Or at least less than the 101 queries. I've tried putting in ModelA.objects.select_related().all() but this didn't seem to have any effect. Thanks

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  • Parsing C# Script into Java

    - by pantaryl
    I'm looking for a way to easily read in a C# file and place it into a Java Object for database storage (storing the class name, functions, variables, etc). I'm making a Hierarchical State Machine AI Building Tool for a game I'm creating and need to be able to import an existing C# file and store it in a database for retrieval in the future. Does anyone know of any preexisting libraries for parsing C# files? Something similar to JavaParser? Thanks everyone! EDIT: This needs to be part of my Java Project. I'll be loading in the C# files through my Java Application and saving it into my db4o database.

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  • Order of execution and style of coding in Python

    - by Jason
    Hi guys. I am new to Python so please don't flame me if the question is too basic :) I have read that Python is executed from top - to - bottom. If this is the case, why do programs go like this: def func2(): def func1(): #call func2() def func() #call func1() if __name__ == '__main__': call func() So from what I have seen, the main function goes at last and the other functions are stacked on top of it. Am I wrong in saying this? If no, why isn't the main function or the function definitions written from top to bottom?

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  • How to define a new type (class) in Python using C API?

    - by ~mech
    Hi, I am trying to use the Python C API to define a new class inside a module that would expose certain functionality written in C to Python code. I specifically want to have it in the form of a class and not a set of module functions. However, I can't find anything regarding this particular task in the official documentation. The closest I could find is PyClass_New function (in the Python.h header) but it is not mentioned anywhere in the official docs, so I assume it is not supposed to be used. So, what is the proper way to define a new Python class from C code? Thanks.

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  • from JS to iphone dev - what's the best language to start with?

    - by Enkai
    I am a total beginner and would like to eventually learn to develop for the iphone. I have just done a beginner's CS course where the language we learned was JavaScript. We studied basic concepts like: variables, arrays, loops (for,while,if,if..else..), properties and functions. I'm wondering if I am starting in the right/wrong place by following this book: Learn C on the Mac by Dave Mark? I have read a few chapters and am finding it a bit hard to get my head around the way that C works, for example the way that Strings are printed seems overly complicated as compared to JS. Do you think that JS was the wrong language to start off with and would I be better to go from JS straight to Objective-C rather than to C? I have tried to read up on previous threads on the merits/demerits of learning C first but haven't found any that relate JS to learning C/Obj C/ Cocoa. Any advice appreciated as I am very new to this. Thanks

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  • how to make a simple database app in android?

    - by Iakovl
    i am not an android developer, prefer C# but i want to play with andorid a bit since i have a android device, apologize in advance for it. i want to make a simple app in android with the basic CRUD functions (create, read, update and delete) while the basic option is to use SQLiteOpenHelper i've seen DAO generators (like greenDAO) that make life more simple as i see it. so the first question is what DAOgenerator to use (if it all)? next is how to properly show it, while i know i need listview i still don't figure out exactly how to bind the database to it and to the querys i'll make for proper display each time i make a new query from a "search" screen, to the main "list display" screen

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  • On which Windows versions and configurations does my C++ app run?

    - by saas
    I've built a C++ application using MSVC 2010, default compile settings (note: Using "Multithreaded" instead of "Multithreaded DLL" to avoid the Microsoft C++ runtime being needed). I used only the STL and a few, old functions from the Win32 API (Windows.h). Where will my app run? (98-7?) Can the be any differences on how my app works on different PCs? As said: It's only a simple console app. I'd be glad if you could add some additional information if you have it!

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  • Jquery - How to make $.post() use contentType=application/json?

    - by JK
    I've noticed that when using $.post() in jquery that the default contentType is application/x-www-form-urlencoded - when my asp.net mvc code needs to have contentType=application/json (See this question for why I must use application/json: http://stackoverflow.com/questions/2792603/aspnet-mvc-why-is-modelstate-isvalid-false-the-x-field-is-required-when-that) How can I make $.post() send contentType=application/json? I already have a large number of $.post() functions, so I don't want to change to $.ajax() because it would take too much time If I try $.post(url, data, function(), "json") It still has contentType=application/x-www-form-urlencoded. So what exactly does the "json" param do if it does not change the contenttype to json? If I try $.ajaxSetup({ contentType: "application/json; charset=utf-8" }); That works but affects every single $.get and $.post that I have and causes some to break. So is there some way that I can change the behavior of $.post() to send contentType=application/json?

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  • PHP: Remove blank line before text

    - by Bailey
    Occasionally, my email-to-support-ticket system catches an extra line break before the message itself, thus my messages look like this: " Hello. I have been wondering if y..." What can I use to get rid of that line before the text? It is on random occasion due to email providers and the way they format their emails using mime. I have already tried the trim functions but no luck. (Yes, I also tried ltrim) Once processed it should look like: "Hello. I have been wondering if y..."

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  • How should I use try...except while defining a function?

    - by SpawnCxy
    Hi all, I find I've been confused by the problem that when I needn't to use try..except.For last few days it was used in almost every function I defined which I think maybe a bad practice.For example: class mongodb(object): def getRecords(self,tname,conditions=''): try: col = eval("self.db.%s" %tname) recs = col.find(condition) return recs except Exception,e: #here make some error log with e.message What I thought is ,exceptions may be raised everywhere and I have to use try to get them. And my question is,is it a good practice to use it everywhere when defining functions?If not are there any principles for it?Help would be appreciated! Regards

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  • I have some basic questions setting up a PHP daemon

    - by mike
    I will be writing my first daemon in php and I have a couple really basic questions that I need help with. 1) What packages need to be installed on my linux server and Does anything in PHP need to be enabled? So far I have gotten this - http://pear.php.net/package/System_Daemon/download 2) Where on server do I save my daemon files? 3) I have a number of files that need to be included within the daemon that contain classes and functions for gathering emails and attachments through IMAP. All of these files are currently in my web public directory, how do I include these files within my daemon? I think that is everything I need to get started. Thanks so much!

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  • Calling a Sub or Function contained in a module using "CallByName" in VB/VBA

    - by Kratz
    It is easy to call a function inside a classModule using CallByName How about functions inside standard module? 'inside class module 'classModule name: clsExample Function classFunc1() MsgBox "I'm class module 1" End Function ' 'inside standard module 'Module name: module1 Function Func1() MsgBox "I'm standard module 1" End Function ' ' The main sub Sub Main() ' to call function inside class module dim clsObj as New clsExample Call CallByName(clsObj,"ClassFunc1") ' here's the question... how to call a function inside a standard module ' how to declare the object "stdObj" in reference to module1? Call CallByName(stdObj,"Func1") ' is this correct? End Sub

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  • Should I convert data arrays to objects in PHP in a CouchDB/Ajax app?

    - by karlthorwald
    I find myself converting between array and object all the time in PHP application that uses couchDB and Ajax. Of course I am also converting objects to JSON and back (for sometimes couchdb but mostly Ajax), but this is not so much disturbing my workflow. At the present I have php objects that are returned by the CouchDB modules I use and on the other hand I have the old habbit to return arrays like array("error"="not found","data"=$dataObj) from my functions. This leads to a mixed occurence of real php objects and nested arrays and I cast with (object) or (array) if necessary. The worst thing is that I know more or less by heart what a function returns, but not what type (array or object), so I often run into type errors. My plan is now to always cast arrays to objects before returning from a function. Of course this implies a lot of refactoring. Is this the right way to go? What about the conversion overhead? Other ideas or tips?

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  • writing structs and classes to disk

    - by Phenom
    The following function writes a struct to a file. int btwrite(short rrn, BTPAGE *page_ptr) { long addr; addr = (long) rrn * (long) PAGESIZE + HEADERSIZE; lseek(btfd, addr, 0); return (write(btfd, page_ptr, PAGESIZE)); } The following is the struct. typedef struct { short keycount; /* number of keys in page */ int key[MAXKEYS]; /* the actual keys */ int value[MAXKEYS]; /* the actual values */ short child[MAXKEYS+1]; /* ptrs to rrns of descendants */ } BTPAGE; What would happen if I changed the struct to a class, would it still work the same? If I added class functions, would the size it takes up on disk increase?

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