Search Results

Search found 14213 results on 569 pages for 'distributed programming'.

Page 527/569 | < Previous Page | 523 524 525 526 527 528 529 530 531 532 533 534  | Next Page >

• Vector Usage in MPI(C++)

  - by lsk1985

  I am new to MPI programming,stiil learning , i was successful till creating the Derived data-types by defining the structures . Now i want to include Vector in my structure and want to send the data across the Process. for ex: struct Structure{ //Constructor Structure(): X(nodes),mass(nodes),ac(nodes) { //code to calculate the mass and accelerations } //Destructor Structure() {} //Variables double radius; double volume; vector<double> mass; vector<double> area; //and some other variables //Methods to calculate some physical properties Now using MPI i want to sent the data in the structure across the processes. Is it possible for me to create the MPI_type_struct vectors included and send the data? I tried reading through forums, but i am not able to get the clear picture from the responses given there. Hope i would be able to get a clear idea or approach to send the data PS: i can send the data individually , but its an overhead of sending the data using may MPI_Send/Recieve if we consider the domain very large(say 10000*10000)

  Read the article

• How to make buttons in python/pygame?

  - by user1334014

  I'm making a game in pygame and on the first screen I want there to be buttons that you can press to (i) start the game, (ii) load a new screen with instructions, and (iii) exit the program. I've found this code online for button making, but I don't really understand it (I'm not that good at object oriented programming). If I could get some explanation as to what it's doing that would be great. Also, when I use it and try to open a file on my computer using the file path, I get the error sh: filepath :Permission denied, which I don't know how to solve. #load_image is used in most pygame programs for loading images def load_image(name, colorkey=None): fullname = os.path.join('data', name) try: image = pygame.image.load(fullname) except pygame.error, message: print 'Cannot load image:', fullname raise SystemExit, message image = image.convert() if colorkey is not None: if colorkey is -1: colorkey = image.get_at((0,0)) image.set_colorkey(colorkey, RLEACCEL) return image, image.get_rect() class Button(pygame.sprite.Sprite): """Class used to create a button, use setCords to set position of topleft corner. Method pressed() returns a boolean and should be called inside the input loop.""" def __init__(self): pygame.sprite.Sprite.__init__(self) self.image, self.rect = load_image('button.png', -1) def setCords(self,x,y): self.rect.topleft = x,y def pressed(self,mouse): if mouse[0] > self.rect.topleft[0]: if mouse[1] > self.rect.topleft[1]: if mouse[0] < self.rect.bottomright[0]: if mouse[1] < self.rect.bottomright[1]: return True else: return False else: return False else: return False else: return False def main(): button = Button() #Button class is created button.setCords(200,200) #Button is displayed at 200,200 while 1: for event in pygame.event.get(): if event.type == MOUSEBUTTONDOWN: mouse = pygame.mouse.get_pos() if button.pressed(mouse): #Button's pressed method is called print ('button hit') if __name__ == '__main__': main() Thank you to anyone who can help me.

  Read the article

• Monads with Join() instead of Bind()

  - by MathematicalOrchid

  Monads are usually explained in turns of return and bind. However, I gather you can also implement bind in terms of join (and fmap?) In programming languages lacking first-class functions, bind is excruciatingly awkward to use. join, on the other hand, looks quite easy. I'm not completely sure I understand how join works, however. Obviously, it has the [Haskell] type join :: Monad m = m (m x) - m x For the list monad, this is trivially and obviously concat. But for a general monad, what, operationally, does this method actually do? I see what it does to the type signatures, but I'm trying to figure out how I'd write something like this in, say, Java or similar. (Actually, that's easy: I wouldn't. Because generics is broken. ;-) But in principle the question still stands...) Oops. It looks like this has been asked before: Monad join function Could somebody sketch out some implementations of common monads using return, fmap and join? (I.e., not mentioning >>= at all.) I think perhaps that might help it to sink in to my dumb brain...

  Read the article

• Why can’t I create a database in an empty ASP MVC 2 project using Project->Add->New Item->SQL Server

  - by Dr Dork

  I'm diving head first into ASP MVC and am playing around with creating and manipulating a database. I did a search and found this tutorial for creating a database, however when I follow it, I get this error right at the start when trying to add a new database to my fresh, empty ASP MVC 2 project... A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) The only requirement the tutorial mentioned was SQL Server Express, but when I went to download it, it said it was already installed. I'm assuming it was part of the VS 2010 RC I installed and am running. So I don't know what else I need if I am missing something. This is all new to me, so I'm sure I'm missing something obvious here and after I'm done posting this question, I plan to do some more research into the topic of databases and how they work with ASP MVC. In the meantime, I was you could help me answer a couple high level questions... What am I missing/forgetting to do that is causing this error? Any suggestions for good resources/tutorials that focus on using databases with ASP MVC? I've done a lot of database programming in the past, so I'm familiar with the concepts of relational databases and the SQL language. I wish I could find a good resource for learning how to work with them in an ASP dev environment, as well as a good breakdown of all the related technologies used for working with them (i.e. LINQ to SQL). Thanks so much in advance for all your help! I'm going to start researching these questions right now.

  Read the article

• How can a B-tree node be represented?

  - by chronodekar

  We're learning B-trees in class and have been asked to implement them in code. The teacher has left choice of programming language to us and I want to try and do it in C#. My problem is that the following structure is illegal in C#, unsafe struct BtreeNode { int key_num; // The number of keys in a node int[] key; // Array of keys bool leaf; // Is it a leaf node or not? BtreeNode*[] c; // Pointers to next nodes } Specifically, one is not allowed to create a pointer to point to the structure itself. Is there some work-around or alternate approach I could use? I'm fairly certain that there MUST be a way to do this within the managed code, but I can't figure it out. EDIT: Eric's answer pointed me in the right direction. Here's what I ended up using, class BtreeNode { public List<BtreeNode> children; // The child nodes public static int MinDeg; // The Minimum Degree of the tree public bool IsLeaf { get; set; } // Is the current node a leaf or not? public List<int> key; // The list of keys ... }

  Read the article

• how do I use an enum value on a switch statement in C++

  - by BotBotPgm

  I would like to use an enum value for my switch statment in C++. Is it possible to use the enum values enclosed in the "{}" as choices for the "switch()"? I know that switch() needs an integer value in order to direct the flow of programming to the appropriate case number. If this is the case, do I just make a variable for each constant in the 'enum' statment? I also want the user to be able to pick the choice and pass that choice to the switch() statement. for example: cout<< "1 - Easy"; cout<<"2 - Medium"; cout<< "3 -Hard"; enum myChoice {EASY =1 ,MEDIUM = 2, HARD = 3} cin ???? switch(????) case 1/EASY: (can I just type case EAST?) cout << "You picked easy!"; break; case 2/MEDIUM: cout << "You picked medium!"; case 3..... (same thing as case 2 except on hard.) default: return 0; Thanks

  Read the article

• Visual Basic: Newbie questions.

  - by Omega

  Hello there. I am starting to learn visual basic. So far, it is quite simple and easy to use. I am liking it! Anyway, I want to make applications a little bit more complex. So far I have done very silly things. I would appreciate if you could help me with these: How do I open a new window (form)? Maybe I click a button on my main form and another form pops up. How do I "deactivate" the main form while the new form is running? (if I try to click the main form, an error sound plays) So my second form has a text field and a "OK" button. If I click it, the second form closes activating the main form again. I want to "pass" the text in the text field from the second form to the first one. How do I do that? Thank you, I am enjoying this new programming environment (didn't use Visual Studio much before)

  Read the article

• How: Start an Activity inside a Thread and use finish() to get back.

  - by Kirk Becker

  Hello, I am programming a game on android. I'm using a Thread while calling a Surface View class to update and draw my game. Inside the update I wanted to start an activity based on if the game has just started and this would launch my MENUS. My Thread for the most part.. while (myThreadRun) { Canvas c = null; try { gameTime = System.currentTimeMillis(); c = myThreadSurfaceHolder.lockCanvas(null); synchronized (myThreadSurfaceHolder) { // Update Game. myThreadSurfaceView.onUpdate(); // Draw Game. myThreadSurfaceView.onDraw(c); You can see there where I am updating the game... here is onUpdate(); protected void onUpdate() { // Test if menu needs to be displayed. while (thread.getMenu()) { // Test if menu activity has been started. if (thread.getMenuRunning() == false) { Intent menuIntent = new Intent(this.getContext(), MyMenu.class); ((Activity) cxt).startActivityForResult(menuIntent, 1); thread.setMenuRunning(true); } } I am using a while loop because if I didn't use it the thread just keeps going. Basically I just don't know how to implement my menus using a thread as a game loop. Everywhere I look it seems like that's best practice. In my menu activity I just display the menu layout and a few buttons and when the person wants to start the game it uses finish() to go back to my thread where they play the game. I am very new to this so any insight will be helpful, Thanks

  Read the article

• Why won't JPA delete owned entities when the owner entity loses the reference to them?

  - by Nick

  Hi! I've got a JPA entity "Request", that owns a List of Answers (also JPA entities). Here's how it's defined in Request.java: @OneToMany(cascade= CascadeType.ALL, mappedBy="request") private List<Answer> answerList; And in Answer.java: @JoinColumn(name = "request", referencedColumnName="id") @ManyToOne(optional = false) private Request request; In the course of program execution, the Request's List of Answers may have Answers added or removed from it, or the actual List object may be replaced. My problem is thus: when I merge a Request to the database, the Answer objects that used to be in the List are kept in the database -- that is, Answer objects that the Request no longer holds a reference to (indirectly, via a List) are not deleted. This is not the behaviour I desire, as if I merge a Request to the database, and then fetch it again, its Answers List may not be the same. Am I making some programming mistake? Is there an annotaion or setting that will ensure that the Answers in the database are exactly the Answers in the Request's List? A solution is to keep references to the original Answers List and then use the EntityManager to remove each old Answer before merging the Request, but it seems like there should be a cleaner way. Thank you!

  Read the article

• Problem with Java Scanner sc.nextLine();

  - by Jonathan B

  Hi, sry about my english :) Im new to Java programming and i have a problem with Scanner. I need to read an Int, show some stuff and then read a string so i use sc.nextInt(); show my stuff showMenu(); and then try to read a string palabra=sc.nextLine(); Some one told me i need to use a sc.nextLine(); after sc.nextInt(); but i dont understand why do you have to do it :( Here is my code: public static void main(String[] args) { // TODO code application logic here Scanner sc = new Scanner(System.in); int respuesta = 1; showMenu(); respuesta = sc.nextInt(); sc.nextLine(); //Why is this line necessary for second scan to work? switch (respuesta){ case 1: System.out.println("=== Palindromo ==="); String palabra = sc.nextLine(); if (esPalindromo(palabra) == true) System.out.println("Es Palindromo"); else System.out.println("No es Palindromo"); break; } } Ty so much for your time and Help :D

  Read the article

• Obj-C Sending Messages Between Classes

  - by user544359

  I'm a newbie in iPhone Programming. I'm trying to send a message from one view controller to another. The idea is that viewControllerA takes information from the user and sends it to viewControllerB. viewControllerB is then supposed to display the information in a label. viewControllerA.h #import <UIKit/UIKit.h> @interface viewControllerA : UIViewController { int num; } -(IBAction)do; @end viewControllerA.m #import "viewControllerA.h" #import "viewControllerB.h" @implementation viewControllerA - (IBAction)do { //initializing int for example num = 2; viewControllerB *viewB = [[viewControllerB alloc] init]; [viewB display:num]; [viewB release]; //viewA is presented as a ModalViewController, so it dismisses itself to return to the //original view, i know it is not efficient [self dismissModalViewControllerAnimated:YES]; } - (void)dealloc { [super dealloc]; } @end viewControllerB.h #import <UIKit/UIKit.h> @interface viewControllerB : UIViewController { IBOutlet UILabel *label; } - (IBAction)openA; - (void)display:(NSInteger)myNum; @end viewControllerB.m #import "viewControllerB.h" #import "viewControllerA.h" @implementation viewControllerB - (IBAction)openA { //presents viewControllerA when a button is pressed viewControllerA *viewA = [[viewControllerA alloc] init]; [self presentModalViewController:viewA animated:YES]; } - (void)display:(NSInteger)myNum { NSLog(@"YES"); [label setText:[NSString stringWithFormat:@"%d", myNum]]; } @end YES is logged successfully, but the label's text does not change. I have made sure that all of my connections in Interface Builder are correct, in fact there are other (IBAction) methods in my program that change the text of this very label, and all of those other methods work perfectly... Any ideas, guys? You don't need to give me a full solution, any bits of information will help. Thanks.

  Read the article

• When to use pointer to a class and when to just instantiate it as a variable

  - by Enders

  Im sort of confused by it. The best I could find was reading through the cplusplus.com tutorial and all they have to say about pointers to classes. "It is perfectly valid to create pointers that point to classes. We simply have to consider that once declared, a class becomes a valid type, so we can use the class name as the type for the pointer" Which tells me nothing about when to use them over the normal instantiation. I've seen the - operator many times, and looked at some codes but cant really decipher why they did it. Generic examples will be appreciated; but more specifically related to gui programming. Its where I encountered it first. QGridLayout *mainLayout = new QGridLayout; mainLayout->addWidget(nameLabel, 0, 0); mainLayout->addWidget(nameLine, 0, 1); mainLayout->addWidget(addressLabel, 1, 0, Qt::AlignTop); mainLayout->addWidget(addressText, 1, 1); Why not QGridLayout mainLayout mainLayout.addWidget ... (It doesnt compile if I change the sample code to that and try it but you get the point) Thanks in advance

  Read the article

• Is inheritance bad nowadays?

  - by mafutrct

  Personally, I think inheritance is a great tool, that, when applied reasonably, can greatly simplify code. However, I seems to me that many modern tools dislike inheritance. Let's take a simple example: Serialize a class to XML. As soon as inheritance is involved, this can easily turn into a mess. Especially if you're trying to serialize a derived class using the base class serializer. Sure, we can work around that. Something like a KnownType attribute and stuff. Besides being an itch in your code that you have to remember to update every time you add a derived class, that fails, too, if you receive a class from outside your scope that was not known at compile time. (Okay, in some cases you can still work around that, for instance using the NetDataContract serializer in .NET. Surely a certain advancement.) In any case, the basic principle still exists: Serialization and inheritance don't mix well. Considering the huge list of programming strategies that became possible and even common in the past decade, I feel tempted to say that inheritance should be avoided in areas that relate to serialization (in particular remoting and databases). Does that make sense? Or am messing things up? How do you handle inheritance and serialization?

  Read the article

• First Time Working With Others?

  - by cam

  I've been at my very first programming job for about 8 months now and I've learned incredible amounts so far. Unfortunately, I'm the sole developer for a small startup company for internal applications. For the first time ever though, I'll be handing off some of my projects to someone else when I leave this job. I've documented all my projects thoroughly (at least I think so), but I still feel nervous about someone else reading my code. For example, I've always done this sort of thing. for (int i = 0; i < blah.length; i++) { //Do stuff } Should I name 'i' something descriptive? It's only a temporary variable, and will only exist within that loop, and it seems that it's pretty obvious what the loop does with 'i'. This is just one example. Another one is that I name variables differently... I don't really conform to a standard of naming besides starting all private members with an underscore. Are there any resources that could show me how to make it easier for the next developer? Are there standards for this type of thing?

  Read the article

• Socket Performance C++ Or C#

  - by modernzombie

  I have to write an application that is essentially a proxy server to handle all HTTP and HTTPS requests from our server (web browsing, etc). I know very little C++ and am very comfortable writing the application features in C#. I have experimented with the proxy from Mentalis (socket proxy) which seems to work fine for small webpages but if I go to large sites like tigerdirect.ca and browse through a couple of layers it is very slow and sometimes requests don't complete and I see broken images and javascript errors. This happens with all of our vendor sites and other content heavy sites. Mentalis uses HTTP 1.0 which I know is not as efficient but should a proxy be that slow? What is an acceptable amount of performance loss from using a proxy? Would HTTP 1.1 make a noticeable difference? Would a C++ proxy be much faster than one in C#? Is the Mentalis code just not efficient? Would I be able to use a premade C++ proxy and import the DLL to C# and still get good performance or would this project call for all C++? Sorry if these are obvious questions but I have not done network programming before.

  Read the article

• Where do you use Java code? Trouble sending .jar files

  - by leigero

  Apologies for the generic nature of this question. I have been learning Java for a few months now, and I've created a few simple projects which have some functionality. I wanted to send the projects to a friend and I'm running into countless errors and struggles. Passing a .jar file is causing "Main class not found" errors when they try to open it. I tried using third party software to wrap the .jar files into an .exe file and the same errors still persist. Beyond that, I'm convinced that passing around .jar files wrapped into .exe files via third party software is NOT how Java was intended to be used. I've read two books on Java and they all talk about structuring the language, but I'm confused about WHERE I'm supposed to be using this code because it has become painfully obvious that it is NOT intended to be passed around in file format. Is this a server programming language? Used on the back end of websites mainly? I'm not sure where one would be using the code written in Java.

  Read the article

• Is there an user-level accessible font table present in Linux?

  - by youngdood

  Hi again Stackoverflow! Since there is this: http://en.wikipedia.org/wiki/Code_page_437 For MSDOS, is there something similar for Linux systems? Is it possible to access that font data via userland program? I would actually just need an access to the actual bit patterns which define the font, and I would do the rendering myself. I'm fairly sure that something like this exists, but I haven't been able to find what exactly is it and how to access it. After all, e.g. text mode console font has to reside somewhere, and I really do hope it is "rawly" accessible somehow for a userland program. Before I forget, I'm programming my program in C, and have access only to the "standard" linux/posix development headers. The only thing I could came up with myself is to use the fonts in /usr/share/fonts, but having to write my own implementations to extract the data from there doesn't sound really an option; I would really want to achieve this with the least amount of bytes possible, so I feel I'm left with finding a standard way of doing this. It's not really feasible for me to store my own 8x8 ASCII-compatible font with the program either(it takes some 1024 bytes(128 chars * 8x8 bits) just to store the font, which is definitely unacceptable for the strict size limits(some < 1024 bytes for code+data) which I am working with), so being able to use the font data stored at the system itself would greatly simplify my task.

  Read the article

• Javascript Application Book

  - by Jormundir

  Can anyone recommend a good book on Javascript module/application development. I'm a Software Engineer, so I don't need all the intro to programming stuff. What I'm really looking for is: How do you bundle the html/css/javascript together so that you can make one include that will load the whole application. I.e.: <div id="myapplication"></div> ... ... <script src="myapplication.js"> Design patterns are always welcome. I've already read Javascript the good parts, and online guides, but it's hard to find a comprehensive guide/tutorial for specifically this. There's a lot of good "this is a javascript application" and "this is a scalable framework", but I haven't had any luck with "This is how you build a javascript application, including the html and css, and this is how you deliver it nicely". I'm building a small application to start, so I'm not interested in scalability and large-scale development practices, just a nice and comprehensive guide to get me off the ground.

  Read the article

• Processor, OS : 32bit, 64 bit

  - by Sandbox

  I am new to programming and come from a non-CS background (no formal degree). I mostly program winforms using C#. I am confused about 32 bit and 64 bit.... I mean, have heard about 32 bit OS, 32 bit processor and based on which a program can have maximum memory. How it affects the speed of a program. There are lot more questions which keep coming to mind. I tried to go through some Computer Organization and Architecture books. But, either I am too dumb to understand what is written in there or the writers assume that the reader has some CS background. Can someone explain me these things in a plain simple English or point me to something which does that. EDIT: I have read things like In 32-bit mode, they can access up to 4GB memory; in 64-bit mode, they can access much much more....I want to know WHY to all such things. BOUNTY: Answers below are really good....esp one by Martin. But, I am looking at a thorough explanation, but in plain simple English.

  Read the article

• Return value of a JQuery autocomplete using an array of objects as its source

  - by user2920430

  In a JQuery autocomplete which uses an array of objects as its source, can I display the label in the INPUT and later access the value? The default behavior is that the value is displayed in the INPUT after selection. In this case the values represent indexes to unique keys in rows in a table. <!doctype html> <html lang="en"> <head> <meta charset="utf-8"> <title>autocomplete demo</title> <link rel="stylesheet" href="http://code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css"> <script src="http://code.jquery.com/jquery-1.9.1.js"></script> <script src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script> </head> <body> <label for="autocomplete">Select a programming language: </label> <input id="autocomplete"> <script> $( "#autocomplete" ).autocomplete({ source: [ { label:"c++", value:1 }, { label: "java", value:2 }, { label: "javascript", value:3 } ] }); </script> </body> </html>

  Read the article

• ANDROID SAX Parser issue

  - by Chris Watson

  Since I am new to java programming, I need a bit of help with this. I stuck on this one issue and can't continue until I get this to work. I am trying to make a string from that includes a preference int. I saved the data and can display the int (just sample code): SharedPreferences prefs=PreferenceManager .getDefaultSharedPreferences(this); list.setText(prefs.getString("list", "22")); now, I have a xml parser that is pulling a url correctly as a static string: public static String feedUrl = String.format("http://www.freshpointmarketing.com/iphone/objects/XML/AND.php?ID=%d", 22); Works great... now my issue...... I need to have the preference "int" become the variable in the string, thus making it not static. static SharedPreferences prefs=PreferenceManager.getDefaultSharedPreferences(this); static int myVariable = prefs.getInt("list1", 22); public static String feedUrl = String.format("http://www.freshpointmarketing.com/iphone/objects/XML/AND.php?ID=%d", myVariable); If I take out all static references, I get an error on this: private void loadFeed(ParserType type){ try{ FeedParser parser = FeedParserFactory.getParser(type); long start = System.currentTimeMillis(); messages = parser.parse(); long duration = System.currentTimeMillis() - start; Log.i("AndroidNews", "Parser duration=" + duration); String xml = writeXml(); Log.i("AndroidNews", xml); List<String> titles = new ArrayList<String>(messages.size()); for (Message msg : messages){ titles.add(msg.getTitle()); } ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.row,titles); this.setListAdapter(adapter); } catch (Throwable t){ Log.e("AndroidNews",t.getMessage(),t); } } thanks

  Read the article

• Python, web log data mining for frequent patterns

  - by descent

  Hello! I need to develop a tool for web log data mining. Having many sequences of urls, requested in a particular user session (retrieved from web-application logs), I need to figure out the patterns of usage and groups (clusters) of users of the website. I am new to Data Mining, and now examining Google a lot. Found some useful info, i.e. querying Frequent Pattern Mining in Web Log Data seems to point to almost exactly similar studies. So my questions are: Are there any python-based tools that do what I need or at least smth similar? Can Orange toolkit be of any help? Can reading the book Programming Collective Intelligence be of any help? What to Google for, what to read, which relatively simple algorithms to use best? I am very limited in time (to around a week), so any help would be extremely precious. What I need is to point me into the right direction and the advice of how to accomplish the task in the shortest time. Thanks in advance!

  Read the article

• int array doesnt get char values

  - by user1780004

  I am absolutely brand new at programming and im not sure how to explain what im doing here. The whole purpose of this piece is to enter values and then print them out in the same order. Now I wanna quit from entering values when pressing 'q' and so I have to scanf for chars but when I assign them back to the int array the values are not the same. Hope that makes any sense to you but in any case heres my code: #include <stdio.h> #include <stdlib.h> #define SIZE 5000 define flush fflush(stdin) main() { int input[SIZE] = {0},i = 0; int counter = 0; char inputs, quit; do { system("cls"); printf("Input number ('q' to quit and display numbers entered): "); flush; scanf("%c",&inputs); flush; if (inputs == 'q') quit = 'q'; else { input[i] = inputs; counter++; i++; } } while (i < SIZE && quit != 'q'); for(i = 0; i < counter; i++){ printf("%i.%i\n", i + 1, input[i]); } system("pause"); } Ive been trying to do this on my own btw and also researched some information online regarding chars but couldnt find anything that would help me. Thanks a lot in advance.

  Read the article

• In C, when do structure names have to be included in structure initializations and definitions?

  - by Tyler

  I'm reading The C Programming Language by K&R and in the section on structures I came across these code snippets: struct maxpt = { 320, 200 }; and /* addpoints: add two points */ struct addpoint(struct point p1, struct point p2) { p1.x += p2.x; p1.y += p2.y; return p1; } In the first case, it looks like it's assigning the values 320 and 200 to the members of the variable maxpt. But I noticed the name of the struct type is missing (shouldn't it be "struct struct_name maxpt = {320, 200}"? In the second case, the function return type is just "struct" and not "struct name_of_struct". I don't get why they don't include the struct names - how does it know what particular type of structure it's dealing with? My confusion is compounded by the fact that in previous snippets they do include the structure name, such as in the return type for the following function, where it's "struct point" and not just "struct". Why do they include the name in some cases and not in others? /* makepoint: make a point from x and y components */ struct point makepoint(int x, int y) { struct point temp; temp.x = x; temp.y = y; return temp; }

  Read the article

• STLifying C++ classes

  - by shambulator

  I'm trying to write a class which contains several std::vectors as data members, and provides a subset of vector's interface to access them: class Mesh { public: private: std::vector<Vector3> positions; std::vector<Vector3> normals; // Several other members along the same lines }; The main thing you can do with a mesh is add positions, normals and other stuff to it. In order to allow an STL-like way of accessing a Mesh (add from arrays, other containers, etc.), I'm toying with the idea of adding methods like this: public: template<class InIter> void AddNormals(InIter first, InIter last); Problem is, from what I understand of templates, these methods will have to be defined in the header file (seems to make sense; without a concrete iterator type, the compiler doesn't know how to generate object code for the obvious implementation of this method). Is this actually a problem? My gut reaction is not to go around sticking huge chunks of code in header files, but my C++ is a little rusty with not much STL experience outside toy examples, and I'm not sure what "acceptable" C++ coding practice is on this. Is there a better way to expose this functionality while retaining an STL-like generic programming flavour? One way would be something like this: (end list) class RestrictedVector<T> { public: RestrictedVector(std::vector<T> wrapped) : wrapped(wrapped) {} template <class InIter> void Add(InIter first, InIter last) { std::copy(first, last, std::back_insert_iterator(wrapped)); } private: std::vector<T> wrapped; }; and then expose instances of these on Mesh instead, but that's starting to reek a little of overengineering :P Any advice is greatly appreciated!

  Read the article

< Previous Page | 523 524 525 526 527 528 529 530 531 532 533 534  | Next Page >