Search Results

Search found 15292 results on 612 pages for 'array formulas'.

Page 563/612 | < Previous Page | 559 560 561 562 563 564 565 566 567 568 569 570  | Next Page >

• populating an nsarray

  - by MoKaM

  I intend to make a program that does the following: Create an NSArray populated with numbers from 1 to 100,000. Loop over some code that deletes certain elements of the NSArray when certain conditions are met. Store the resultant NSArray. However the above steps will also be looped over many times and so I need a fast way of making this NSArray that has 100,000 number elements. So what is the fastest way of doing it? Is there an alternative to iteratively populating an Array using a for loop? Such as an NSArray method that could do this quickly for me? Or perhaps I could make the NSArray with the 100,000 numbers by any means the first time. And then create every new NSArray (for step 1) by using method arraywithArray? (is it quicker way of doing it?) Or perhaps you have something completely different in mind that will achieve what I want. edit: Replace NSArray with NSMutableArray in this post.

  Read the article

• why doesnt this program print?

  - by Alex

  What I'm trying to do is to print my two-dimensional array but i'm lost. The first function is running perfect, the problem is the second or maybe the way I'm passing it to the "Print" function. #include <stdio.h> #include <stdlib.h> #define ROW 2 #define COL 2 //Memory allocation and values input void func(int **arr) { int i, j; arr = (int**)calloc(ROW,sizeof(int*)); for(i=0; i < ROW; i++) arr[i] = (int*)calloc(COL,sizeof(int)); printf("Input: \n"); for(i=0; i<ROW; i++) for(j=0; j<COL; j++) scanf_s("%d", &arr[i][j]); } //This is where the problem begins or maybe it's in the main void print(int **arr) { int i, j; for(i=0; i<ROW; i++) { for(j=0; j<COL; j++) printf("%5d", arr[i][j]); printf("\n"); } } void main() { int *arr; func(&arr); print(&arr); //maybe I'm not passing the arr right ? }

  Read the article

• Get class instance by class name string

  - by VDVLeon

  Hi all, I noticed the function Object.factory(char[] className) in D. But it does not work like I hoped it would work; it does not work ;) An example: import std.stdio; class TestClass { override string toString() { return typeof(this).stringof; // TestClass } }; void main(string[] args) { auto i = Object.factory("TestClass"); if (i is null) { writeln("Class not found"); } else { writeln("Class string: " ~ i); } } I think this should result in the message: "Class string: TestClass" but it says "Class not found". Does anybody know why this happens and how I could fix it ? Or do I need to make my own class factory. For example by make a class with a static array Object[string] classes; with class instances. When I want a new instance I do this: auto i = (className in classes); if (i is null) { return null; } return i.classinfo.create();

  Read the article

• Is there a way to make sure classes implementing an Interface implement static methods?

  - by Tobias Kienzler

  Frist of all, I read erickson's usefull reply to "Why can’t I define a static method in a Java interface?". This question is not about the "why" but about the "how then?". So basically I want one Interface to provide both usual methods and e.g. a getSimilarObject method. For (a made up) example public interface ParametricFunction { /** @return f(x) using the parameters */ static abstract public double getValue(double x, double[] parameters); /** @return The function's name */ static abstract public String getName(); } and then public class Parabola implements ParametricFunction { /** @return f(x) = parameters[0] * x² + parameters[1] * x + parameters[2] */ static public double getValue(double x, double[] parameters) { return ( parameters[2] + x*(parameters[1] + x*parameters[0])); } static public String getName() { return "Parabola"; } } Since this is not allowed in the current Java standard, what is the closest thing to this? The idea behind this is putting several ParametricFunction's in a package and use Reflection to list them all, allowing the user to pick e.g. which one to plot. Obviously one could provide a loader class containing an array of the available ParametricFunction's, but every time a new one is implemented one has to remember adding it there, too.

  Read the article

• Finding out inside which iframe a script is executing

  - by juandopazo

  I have a page with several iframes. One of this iframes has a page from a different domain. Inside this iframe there's another iframe with a page from the parent domain. my page from mydomain.com -> an iframe -> iframe "#foo" from another-domain.com> -> iframe "#bar" from mydomain.com -> another iframe I need to get a reference to the "#foo" node inside the main page. The security model should allow me to do that because "#bar" has the same domain as the main page. So what I'm doing is iterating through the window.top array and comparing each element to the window object which is currently the "#bar" window object. My test code looks like: for (var i = 0; i < top.length; i++) { for (var j = 0; j < top[i].length; j++) { if (top[i][j] == window) { alert("The iframe number " + i + " contains me"); } } } This works fine in all browsers, but Internet Explorer 6 throws a security error when accesing top[i][j]. Any ideas on how to solve this on IE6? Thanks!

  Read the article

• Can I automate a loop query based on category with the page's title?

  - by jordaninternets

  To explain further, I need to get a page to display posts from a specific category. I want to automate this process so I don't have to make a template for each category. How would I do that? (keep in mind the person I'm building this is for has no coding experience.) The only way I could think off from the top of my head is to use the title or slug. So if the category is named the same thing as the slug, could I filter by category using the slug? Maybe this isn't the best way... what should I do? This is what I came up with, but it doesn't work, I'm sure due to improper use on may part, but I've been pouring over the WP codex and Google with no avail to tell me my problem. <?php $paged = (get_query_var('paged')) ? get_query_var('paged') : 1; $args= array( 'orderby' => 'date', 'order' => 'ASC', 'paged' => $paged, 'category_name' => echo the_title('\'','\'',) ); query_posts($args); ?>

  Read the article

• Beginnerquestion: How to count amount of each number drawn in a Lottery and output it in a list?

  - by elementz

  I am writing this little Lottery application. Now the plan is, to count how often each number has been drawn during each iteration of the Lottery, and store this somewhere. My guess is that I would need to use a HashMap, that has 6 keys and increments the value by one everytime the respective keys number is drawn. But how would I accomplish this? My code so far: public void numberCreator() { // creating and initializing a Random generator Random rand = new Random(); // A HashMap to store the numbers picked. HashMap hashMap = new HashMap(); // A TreeMap to sort the numbers picked. TreeMap treeMap = new TreeMap(); // creating an ArrayList which will store the pool of availbale Numbers List<Integer>numPool = new ArrayList<Integer>(); for (int i=1; i<50; i++){ // add the available Numbers to the pool numPool.add(i); hashMap.put(nums[i], 0); } // array to store the lotto numbers int [] nums = new int [6]; for (int i =0; i < nums.length; i++){ int numPoolIndex = rand.nextInt(numPool.size()); nums[i] = numPool.get(numPoolIndex); // check how often a number has been called and store the new amount in the Map int counter = hashMap.get numPool.remove(numPoolIndex); } System.out.println(Arrays.toString(nums)); } Maybe someone can tell me if I have the right idea, or even how I would implement the map properly?

  Read the article

• How to output multiple rows from an SQL query using the mysqli object

  - by Jonathan

  Assuming that the mysqli object is already instantiatied (and connected) with the global variable $mysql, here is the code I am trying to work with. class Listing { private $mysql; function getListingInfo($l_id = "", $category = "", $subcategory = "", $username = "", $status = "active") { $condition = "`status` = '$status'"; if (!empty($l_id)) $condition .= "AND `L_ID` = '$l_id'"; if (!empty($category)) $condition .= "AND `category` = '$category'"; if (!empty($subcategory)) $condition .= "AND `subcategory` = '$subcategory'"; if (!empty($username)) $condition .= "AND `username` = '$username'"; $result = $this->mysql->query("SELECT * FROM listing WHERE $condition") or die('Error fetching values'); $this->listing = $result->fetch_array() or die('could not create object'); foreach ($this->listing as $key => $value) : $info[$key] = stripslashes(html_entity_decode($value)); endforeach; return $info; } } there are several hundred listings in the db and when I call $result-fetch_array() it places in an array the first row in the db. however when I try to call the object, I can't seem to access more than the first row. for instance: $listing_row = new Listing; while ($listing = $listing_row-getListingInfo()) { echo $listing[0]; } this outputs an infinite loop of the same row in the db. Why does it not advance to the next row? if I move the code: $this->listing = $result->fetch_array() or die('could not create object'); foreach ($this->listing as $key => $value) : $info[$key] = stripslashes(html_entity_decode($value)); endforeach; if I move this outside the class, it works exactly as expected outputting a row at a time while looping through the while statement. Is there a way to write this so that I can keep the fetch_array() call in the class and still loop through the records?

  Read the article

• remove row on click on specific td of that row by jquery

  - by I Like PHP

  i have an table <table class="oldService"> <thead> <th>name</th> <th>age</th> <th>action</th> </thead> <tbody> <?php foreach($array as $k=>$v){ ?> <tr> <td><?php echo $k[name] ?></td> <td><?php echo $k[age]?></td> <td id="<?php $k[id]" class="delme">X</td> </tr> <?php } ?> </tbody> <table> now i want to delete any row by clicking on X of each row except first and last row, and also need to confirm before deletion. i used below jquery <script type="text/javascript"> jQuery(document).ready(function(){ jQuery('table.oldService>tbody tr').not(':first').not(':last').click(function(){ if(confirm('want to delete!')){ jQuery(jQuery(this).addClass('del').fadeTo(400, 0, function() { jQuery(this).remove()})); jQuery.get('deleteService.php', {id:jQuery(this).attr('id')}); } else return false;}); }); </script> this is working perfect,but it execute by click on that row( means any td), i want that this event only occour when user click on X(third td) . please suggest me how to modify this jquery so that the event occur on click of X.

  Read the article

• Google maps api Directions User defined Steps

  - by Via Lactea

  Hi All, I have a google map service with the stores mapped on it. I also have directions service (then you define two addresses or more and it shows you a way on this map, see google map api directions). So I wa?? to show the nearest stores to this way. Of course it could be the store located in the next streat of my way, so it also should be included to the list. So far I just found only an array of steps in the directions object which I get from google maps api. But these steps are predefined by google, so they can be too close one each to other and they also can be too far (if a part of your route is a highway or there is no any special steps on your way etc.) So, what I want to do. I want to make my own steps on the line that I get from google directions (for example to put these steps on my line every 500 meeters etc.), and after that to search every step for any stores around 200 meeters. Is it possible to do? I cannot find any solution of this idea in internet.

  Read the article

• How to sort NSMutableArray? Code review needed

  - by JAM

  Good evening. This code works. It sorts an array of cards by both Suit and Card Value. It is also very much brute force. Can you recommend a better way? Does Objective-C help dealing with a situation where object being sorted itself has multiple fields, on which sorting depends? -(void) sort: (NSMutableArray *) deck { NSUInteger count = [deck count]; Card *thisCard; Card *nextCard; int this; int next; BOOL stillSwapping = true; while (stillSwapping) { stillSwapping = false; for (NSUInteger i = 0; i < count; ++i) { this = i; next = i+1; if (next < count) { thisCard = [deck objectAtIndex:this]; nextCard = [deck objectAtIndex:next]; if ([thisCard suit] > [nextCard suit]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } if ([thisCard suit] == [nextCard suit]) { if ([thisCard value] > [nextCard value]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } } } } } }

  Read the article

• Discussion - Allowing / blocking user access to pages / Client Side Validation (Client Side Only!) -

  - by Ozaki

  TLDR Using plain HTML / Javascript (Client Side) I want to prevent viewing of certain pages. The user will have to type a username and password and depending on that they get access to different pages. Answers can NOT include server side whatsoever It does not matter if they can break it easily. There is no sensitive information etc. Also the target audience will not have access to internet OR probably know what a cookie is... At some point the user will have to type username / password.(I can define the cookie here) Currently I thought of using cookies to set a cookie for each page to say "true" / "false" but that would get messy with so many cookies. Or setting an array within a cookie for each page? I have div field "#Content" which as it looks encompasses all of my content on the page so blocking out content will be as simple as replacing it with ("sorry you don't have access") etc. For Example: $.cookie("Access","page1, page2, page3"{ expires: 1 }); I am looking for anyway to do this does not have to be with cookies. Would be nice to get a discussion of different ways this can be done. So the question is: What do YOU think would be a good way to go about doing this with client side validation? Also on another note discussion on how to make client side more secure or ways to do so are acceptable.

  Read the article

• How to select a single object using Linq in vb.net

  - by Hucker

  I have done a lot of searching to what appears to be a simple LINQ problem but I can't figure out how to do grab an object out of a collection that has a specified minimum (or max value) without resorting to a sort like this: > dim customers= GetCustomers() > > dim youngest = (From c in customers > Order By c.age Ascending).ToList.First This (untested code) structure works fine with the exception that the entire customer array must be sorted and placed into a list for the only purpose of extracting the first value. That can't be the best way to get the minimum! Note that I want the whole c record in this case, not the minumum age of a customer that can be done like this (a typical example): > dim customers= GetCustomers() > > dim youngest = (From c in customers > Select c.age).Min Or even > dim customers= GetCustomers() > > dim youngest = (From c in customers > Select c).Min(Function(x) x.age) I can't for the life of me figure out how to get the whole object (or even the index) without resorting to the sort...

  Read the article

• Why is it possible to enumerate a LinqToSql query after calling Dispose() on the DataContext?

  - by DanM

  I'm using the Repository Pattern with some LinqToSql objects. My repository objects all implement IDisposable, and the Dispose() method does only thing--calls Dispose() on the DataContext. Whenever I use a repository, I wrap it in a using person, like this: public IEnumerable<Person> SelectPersons() { using (var repository = _repositorySource.GetNew<Person>(dc => dc.Person)) { return repository.GetAll(); } } This method returns an IEnumerable<Person>, so if my understanding is correct, no querying of the database actually takes place until Enumerable<Person> is traversed (e.g., by converting it to a list or array or by using it in a foreach loop), as in this example: var persons = gateway.SelectPersons(); // Dispose() is fired here var personViewModels = ( from b in persons select new PersonViewModel { Id = b.Id, Name = b.Name, Age = b.Age, OrdersCount = b.Order.Count() }).ToList(); // executes queries In this example, Dispose() gets called immediately after setting persons, which is an IEnumerable<Person>, and that's the only time it gets called. So, a couple questions: How does this work? How can a disposed DataContext still query the database for results when I walk the IEnumerable<Person>? What does Dispose() actually do? I've heard that it is not necessary (e.g., see this question) to dispose of a DataContext, but my impression was that it's not a bad idea. Is there any reason not to dispose of it?

  Read the article

• Read all sub directories within a certain folder to display a random image.

  - by Andy

  I have this code i have been using....but i need a conditional where it will read all the sub directories of /bg to select an image as opposed to a specific folder if they were on a subpage. Heres my code so far which works perfectly for all subpages to display specific images: //This would tell us its on the homepage if it helps: $this->level() == 0 //This is the code so far $path = '/home/sites/mydomain.co.uk/public_html/public/images/bg/'.$this->slug; $homepagefile = URL_PUBLIC.'public/images/bg/'.$this->slug.'/main.jpg'; $bgimagearray = array(); $iterator = new DirectoryIterator($path); foreach ($iterator as $fileinfo) { if ($fileinfo->isFile() && !preg_match('\.jpg$/', $fileinfo->getFilename())) { $bgimagearray[] = "'" . $fileinfo->getFilename() . "'"; } } $bgimage = array_rand($bgimagearray); ?> <div id="bg"> <div> <table cellspacing="0" cellpadding="0"> <tr> <td><img src="<?php echo $file.trim($bgimagearray[$bgimage], "'"); ?>" alt=""/></td> </tr> </table> </div> </div> Any help would be appreciated, im sure its not rocket science but ive tried a few ways and cant get my head around it. Thanks in advance.

  Read the article

• Applying a function that may fail to all values in a list

  - by Egwor

  I want to apply a function f to a list of values, however function f might randomly fail (it is in effect making a call out to a service in the cloud). I thought I'd want to use something like map, but I want to apply the function to all elements in the list and afterwards, I want to know which ones failed and which were successful. Currently I am wrapping the response objects of the function f with an error pair which I could then effectively unzip afterwards i.e. something like g : (a->b) -> a -> [ b, errorBoolean] f : a-> b and then to run the code ... map g (xs) Is there a better way to do this? The other alternative approach was to iterate over the values in the array and then return a pair of arrays, one which listed the successful values and one which listed the failures. To me, this seems to be something that ought to be fairly common. Alternatively I could return some special value. What's the best practice in dealing with this??

  Read the article

• Make a PHP GET request from a PHP script and exit

  - by Abs

  Hello all, Is there something simpler than the following. I am trying to make a GET request to a PHP script and then exit the current script. I think this is a job for CURL but is there something simpler as I don't want to really worry about enabling the CURL php extension? In addition, will the below start the PHP script and then just come back and not wait for it to finish? //set GET variables $url = 'http://domain.com/get-post.php'; $fields = array( 'lname'=>urlencode($last_name), 'fname'=>urlencode($first_name) ); //url-ify the data for the GET foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; } rtrim($fields_string,'&'); //open connection $ch = curl_init(); //set the url, number of POST vars, POST data curl_setopt($ch,CURLOPT_URL,$url); curl_setopt($ch,CURLOPT_GET,count($fields)); curl_setopt($ch,CURLOPT_GETFIELDS,$fields_string); //execute GET $result = curl_exec($ch); //close connection curl_close($ch); I want to run the other script which contains functions when a condition is met so a simple include won't work as the if condition wraps around the functions, right? Please note, I am on windows machine and the code I am writing will only be used on a Windows OS. Thanks all for any help and advice

  Read the article

• Should I really use a UITableView in this situation?

  - by mystify

  Imagine you have a view like this: At the top, there is an UISegmentedControl with two segments. It functions like a tab. Pressing one segment will activate this particular content below that UISegmentedControl. Below the UISegmentedControl are some switches. These modify the way how the content should be rendered. And finally, below those switches, there's a table. Imagine a table not in sense of UITableView, but just what it really is: A table. It shows little messages like twitter messages or chat messages for example, one below the other. Like you know it from skype and other chats. Basically they're just rows with some formatting. A label, some image views, some lines, a background. Pretty basic. The data comes from an array. No core data. The whole thing including the segmented control and setup switches must be scrollable. So what I did is: I put all this stuff in an UIScrollView. Now I have to make the decision if I would use a UITableView inside there for that table part, or if I would just print a lot of rows on to the scroll view (with -drawRect:). But some problems stick in my head: Can I put a UITableView inside a UIScrollView? I assume this makes a lot of problems. I don't want that the table part is separately scrollable. Again imagine that view: First there are some basic choice things (segmented control, switches). Then there comes the table. When you scroll, the whole thing scrolls. That's mainly because this first part with the settings can be pretty big, so you would want to scroll it away. The next thing is: Can I customize UITableView in such a way, that it consists of two parts? One for that settings part, and one for the actual data to display?

  Read the article

• What would be the best approach to finding a date in a freeform text?

  - by Matthew DeVos

  What would be the best approach to finding a date in a freeform text? A post where a user may place a date in it in several different ways such as: July 14th & 15th 7/14 & 7/15 7-14 & 7-15 Saturday 14th and Sunday 15th Saturday July 14th and 15th and so on. Is regex my best choice for this type of thing with preg_match? I would also like to search if there are two dates, one for a start date and a second for an end date, but in the text I'm searching there may be one date or two. This is my PHP code so far: $dates1 = '01-01'; $dates2 = 'July 14th & 15th'; $dates3 = '7/14 & 7/15'; $dates4 = '7-14 & 7-15'; $dates5 = 'Saturday 14th and Sunday 15th'; $dates6 = 'Saturday July 14th and 15th'; $regexes = array( '/\s(1|2|3|4|5|6|7|8|9|10|11|12)\/\d{1,2}/', //finds a date '/\s(1|2|3|4|5|6|7|8|9|10|11|12)-\d{1,2}/', //finds another date '%\b(0?[1-9]|[12][0-9]|3[01])[- /.](0?[1-9]|1[012])\b%', //finds date format dd-mm or dd.mm ); foreach($regexes as $regex){ preg_match($regex,$dates,$matches); } var_dump($matches);

  Read the article

• Need Help: adding MouseListeners to JComponents (Drawing a JComponent and then attaching a MouseListener)

  - by user1074574

  Drawing a JComponent and then attaching a MouseListener seems very simple to me, but not in this case: I'm having a problem with a MouseListener attached to a child JComponent; here's some brief code to help describe it: Note: The BGT class has implemented ActionListers/MouseListeners that do not have any code in them, and 'figures' is an array of SwingThings. public class GC extends BGT{ public GC(){ super(); buildJMenu(); drawPanel.addMouseListener(this); //drawPanel being the panel that draws the JComponents (it is a public variable in the BGT class) drawPanel.addMouseMotionListener(this); this.addMouseListener(this); } public static void main(String[] args){ GC a = new GC(); }... public void mouseClicked(MouseEvent e) { System.out.println(e.getSource()); //This only seems to print out the DrawPanel's information }... public void mouseReleased(MouseEvent e) { repaint(); ... tempMyJTextField = new MyJTextField(startX, startY, width, height); tempMyJTextField.addMouseListener(this); tempMyJTextField.addMouseMotionListener(this); figures.add(tempMyJTextField); for(int i = 0; i < figures.size(); i++) figures.get(i).addTo(drawPanel); } This is the addTo method in the MyJTextField class: public class MyJTextField extends JTextField implements SwingThing{ ... public void addTo(JPanel p) { p.add(myTextField); } ... } In the MouseClicked event it never registers that the JComponent was clicked. (The drawing/painting works fine) Thanks.

  Read the article

• Top n items in a List ( including duplicates )

  - by Krishnan

  Trying to find an efficient way to obtain the top N items in a very large list, possibly containing duplicates. I first tried sorting & slicing, which works. But this seems unnnecessary. You shouldn't need to sort a very large list if you just want the top 20 members. So I wrote a recursive routine which builds the top-n list. This also works, but is very much slower than the non-recursive one! Question: Which is my second routine (elite2) so much slower than elite, and how do I make it faster ? My code is attached below. Thanks. import scala.collection.SeqView import scala.math.min object X { def elite(s: SeqView[Int, List[Int]], k:Int):List[Int] = { s.sorted.reverse.force.slice(0,min(k,s.size)) } def elite2(s: SeqView[Int, List[Int]], k:Int, s2:List[Int]=Nil):List[Int] = { if( k == 0 || s.size == 0) s2.reverse else { val m = s.max val parts = s.force.partition(_==m) val whole = if( parts._1.size > 1) parts._1.tail:::parts._2 else parts._2 elite2( whole.view, k-1, m::s2 ) } } def main(args:Array[String]) = { val N = 1000000/3 val x = List(N to 1 by -1).flatten.map(x=>List(x,x,x)).flatten.view println(elite2(x,20)) println(elite(x,20)) } }

  Read the article

• Error in inserting data into database

  - by Matthew

  When I try to run this code it will not insert the data into the database? <?php class Database { private $dsn; function __construct($dbname, $host, $user, $password, $enckey) { $this->dsn = "mysql:dbname=" . $dbname . ';host=' . $host; $this->user = $user; $this->password = $password; } private function createDSN() { return $this->dsn; } public function createConnection() { try { $dbh = new PDO(self::createDSN(), $this->user, $this->password); } catch (PDOException $e) { echo 'Connection failed: ' . $e->getMessage(); } return $dbh; } } $db = new Database('mytest', 'localhost', 'root', 'hashedpassword', null); $dbh = $db->createConnection(); $sql = $dbh->prepare("INSERT INTO contacts (firstname, lastname) VALUES (?,?)"); $sql->execute(array("abc", "xyz")); ?>

  Read the article

• question about siftdown operation on heap

  - by davit-datuashvili

  i have following pseudo code which execute siftdown operation on heap array suppose is x void siftdown(int n) pre heap(2,n) && n>=0 post heap(1,n) i=1; loop /*invariant heap(1,n) except perhaps between i and it's (0,1,or 2) children*/ c=2*i; if (c>n) break; // c is left child of i if (c+1)<=n /* c+1 is rigth child of i if (x[c+1]<x[c]) c++ /* c is lesser child of i if (x[i]<=x[c]) break; swap(c,i) i=c; i have wrote following code is it correct? public class siftdown{ public static void main(String[]args){ int c; int n=9; int a[]=new int[]{19,100,17,2,7,3,36,1,25}; int i=1; while (i<n){ c=2*i; if (c>n) break; //c is the left child of i if (c+1<=n) //c+1 ir rigth child of i if (a[c+1]<a[c]) c++; if (a[i]<=a[c]) break; int t=a[c]; a[c]=a[i]; a[i]=t; i=c; } for (int j=0;j<a.length;j++){ System.out.println(a[j]); } } } // result is 19 2 17 1 7 3 36 100 25

  Read the article

• Value types of variable size

  - by YellPika

  I'm trying to code a small math library in C#. I wanted to create a generic vector structure where the user could define the element type (int, long, float, double, etc.) and dimensions. My first attempt was something like this... public struct Vector<T> { public readonly int Dimensions; public readonly T[] Elements; // etc... } Unfortunately, Elements, being an array, is also a reference type. Thus, doing this, Vector<int> a = ...; Vector<int> b = a; a[0] = 1; b[0] = 2; would result in both a[0] and b[0] equaling 2. My second attempt was to define an interface IVector<T>, and then use Reflection.Emit to automatically generate the appropriate type at runtime. The resulting classes would look roughly like this: public struct Int32Vector3 : IVector<T> { public int Element0; public int Element1; public int Element2; public int Dimensions { get { return 3; } } // etc... } This seemed fine until I found out that interfaces seem to act like references to the underlying object. If I passed an IVector to a function, and changes to the elements in the function would be reflected in the original vector. What I think is my problem here is that I need to be able to create classes that have a user specified number of fields. I can't use arrays, and I can't use inheritance. Does anyone have a solution? EDIT: This library is going to be used in performance critical situations, so reference types are not an option.

  Read the article

• What is wrong with this append func in C

  - by LuckySlevin

  My Struct Definitions. typedef struct inner_list {char word[100]; inner_list*next;} inner_list; typedef struct outer_list { char word [100]; inner_list * head; outer_list * next; } outer_list; And The problem part: void append(outer_list **q,char num[100],inner_list *p) { outer_list *temp,*r; temp = *q; char *str; if(*q==NULL) { temp = (outer_list *)malloc(sizeof(outer_list)); strcpy(temp->word,num); temp->head = p; temp->next=NULL; *q=temp; } else { temp = *q; while(temp->next !=NULL) { temp=temp->next; } r = (outer_list *)malloc(sizeof(outer_list)); strcpy(r->word,num); temp->head = p; r->next=NULL; temp->next=r; } } I don't know what is i'm doing wrong in this append function i'm sending a char array and a linked list to be stored another linked list. But i can't store the linked list in another linked list. I couldn't figure out the problem. Any ideas?

  Read the article

< Previous Page | 559 560 561 562 563 564 565 566 567 568 569 570  | Next Page >