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• Making ANTLR generated class files into one jar file.

  - by prosseek

  With ANTLR, I get some java class files after compilation. And I need to make all the class files into one jar file. I make manifest.mf file that has one line "Main-class: Test" to indicate the main file. I run 'jar cmf manifest.mf hello.jar *.class' to get hello.jar file. But when I try to run 'java -jar hello.jar', I get the following error messages. $ java -jar hello.jar Exception in thread "main" java.lang.NoClassDefFoundError: Test Caused by: java.lang.ClassNotFoundException: Test at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:315) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:330) at java.lang.ClassLoader.loadClass(ClassLoader.java:250) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:398) What's wrong? I get correct result when I run 'java Test'. The example that I used is the source code from the book 'The Definitive ANTLR Reference' that you can download from http://www.pragprog.com/titles/tpantlr/source_code The example is in /tour/trees/. I get a bunch of class files after compiling g and java files.

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• forks in C - exercise

  - by Zka

  I try to repeat and learn more advanced uses and options when cutting trees with forks in the jungle of C. But foolishly I find an example which should be very easy as I have worked with forks before and even written some code, but i can't understand it fully. Here comes : main() { if (fork() == 0) { if (fork() == 0) { printf("3"); } else if ((wait(NULL)) > 0) { printf("2"); } } else { if (fork() == 0) { printf("1"); exit(0); } if (fork() == 0) { printf("4"); } } printf("0"); return 0; } Possible solutions are : 3201040 3104200 1040302 4321000 4030201 1403020 where 2, 5 and 6 are correct answers. First of all, shouldn't there be four zeroes in the output? Second... How does one come to the solution at all? Been doing this on paper for almost an hour and I'm not even close to understanding why the given solution are more correct than the false ones (except for nr3 as it can't end with 2 since a 0 must follow). Anyone with his forks in check who can offer some good explanation?

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• WPF tree data binding

  - by Am

  Hi, I have a well defined tree repository. Where I can rename items, move them up, down, etc. Add new and delete. The data is stored in a table as follows: Index Parent Label Left Right 1 0 root 1 14 2 1 food 2 7 3 2 cake 3 4 4 2 pie 5 6 5 1 flowers 8 13 6 5 roses 9 10 7 5 violets 11 12 Representing the following tree: (1) root (14) (2) food (7) (8) flowers (13) (3) cake (4) (5) pie (6) (9) roeses (10) (11) violets (12) or root food cake pie flowers roses violets Now, my problem is how to represent this in a bindable way, so that a TreeView can handle all the possible data changes? Renaming is easy, all I need is to make the label an updatble field. But what if a user moves flowers above food? I can make the relevant data changes, but they cause a complete data change to all other items in the tree. And all the examples I found of bindable hierarchies are good for non static trees.. So my current (and bad) solution is to reload the displayed tree after relocation change. Any direction will be good. Thanks

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• converting a Tree to newick format. java

  - by Esmond

  I'm having problems converting a binary rooted tree to newick format. The full explanation for such a format can be found: http://code.google.com/p/mrsrf/wiki/NewickTree An example of a newick format would be as follows: for a tree T such as http://www.cs.mcgill.ca/~cs251/OldCourses/1997/topic8/images/completetreetwo.gif the newick representation would be: (((8,9),(10,11)),((12,13),(14,15))) the internal node will become the commas while the leaves will be retained. such trees have internal nodes which will always have 2 children. I have a problem using recursion to come out with this newick format. The output contains far too many nodes and braces. Any comments to resolve this problem is appreciated or even an iterative algorithm would be welcomed import java.util.Stack; public class Tree { .... public String inOrderNewick(Node root, String output) throws ItemNotFoundException { if (root.hasChild()) { output += "("; output += inOrderNewick(root.child1, output); output += ","; output += inOrderNewick(root.child2, output); output += ")"; return output; } else { output += root.getSeq(); return output; } } }

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• text not wrapping around some floated images, wraps in IE & FF but not chrome, safari

  - by Hartley

  This is unlike anything I've read about and I've been totally scratching my head for the last few hours trying to figure out what's going on. I have a hand-coded site @ hartbro.com Part of the site is a blog, in which I include pictures. Here's the HTML code around one of the images that's causing trouble. <a href="blogcontent/090811.jpg" class="img"> <img src="blogcontent/090811.jpg" alt="Downed trees" width="25%" class="floatright" /></a> The storm left as quickly as it came. The sky cleared up and we were glad that the oppressive heat had let up. What I've noticed is that, on some of the blog entries that include more than one image, the 2nd image isn't really floating like its supposed to be, with the text wrapping around it. I figure its got to be some sort of conflict with some CSS that I have that's causing the problem but I just can't figure out what it is. I don't understand how it works in FF & IE but not Chrome or Safari?? Here's all of the relevant CSS, let me know if you need anything else. Thanks in advance. img{ margin:10px; } img.floatleft{ float:left; } img.floatright{ float:right; } edit: here's an screen-shot of what's happening.

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• Generics vs inheritance (whenh no collection classes are involved)

  - by Ram

  This is an extension of this questionand probably might even be a duplicate of some other question(If so, please forgive me). I see from MSDN that generics are usually used with collections The most common use for generic classes is with collections like linked lists, hash tables, stacks, queues, trees and so on where operations such as adding and removing items from the collection are performed in much the same way regardless of the type of data being stored. The examples I have seen also validate the above statement. Can someone give a valid use of generics in a real-life scenario which does not involve any collections ? Pedantically, I was thinking about making an example which does not involve collections public class Animal<T> { public void Speak() { Console.WriteLine("I am an Animal and my type is " + typeof(T).ToString()); } public void Eat() { //Eat food } } public class Dog { public void WhoAmI() { Console.WriteLine(this.GetType().ToString()); } } and "An Animal of type Dog" will be Animal<Dog> magic = new Animal<Dog>(); It is entirely possible to have Dog getting inherited from Animal (Assuming a non-generic version of Animal)Dog:Animal Therefore Dog is an Animal Another example I was thinking was a BankAccount. It can be BankAccount<Checking>,BankAccount<Savings>. This can very well be Checking:BankAccount and Savings:BankAccount. Are there any best practices to determine if we should go with generics or with inheritance ?

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• git clone fails with "index-pack" failed?

  - by gct

  So I created a remote repo that's not bare (because I need redmine to be able to read it), and it's set to be shared with the group (so git init --shared=group). I was able to push to the remote repo and now I'm trying to clone it. If I clone it over the net I get this: remote: Counting objects: 4648, done. remote: Compressing objects: 100% (2837/2837), done. error: git-upload-pack: git-pack-objects died with error.B/s fatal: git-upload-pack: aborting due to possible repository corruption on the remote side. remote: aborting due to possible repository corruption on the remote side. fatal: early EOF fatal: index-pack failed I'm able to clone it locally without a problem, and I ran "git fsck", which only reports some dangling trees/blobs, which I understand aren't a problem. What could be causing this? I'm still able to pull from it, just not clone. I should note the remote git version is 1.5.6.5 while local is 1.6.0.4 I tried cloning my local copy of the repo, stripping out the .git folder and pushing to a new repo, then cloning the new repo and I get the same error, which leads me to believe it may be a file in the repo that's causing git-upload-pack to fail... Edit: I have a number of windows binaries in the repo, because I just built the python modules and then stuck them in there so everyone else didn't have to build them as well. If I remove the windows binaries and push to a new repo, I can clone again, perhaps that gives a clue. Trying to narrow down exactly what file is causing the problem now.

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• What is reading source on an ebook reader like?

  - by Daniel Straight

  There are a few open source projects I would really like to read through the code of to understand better / improve on. The problem is, for me, reading for a long time on the computer screen is tedious. I would love to be able to read code while lounging around and on a screen that was better on my eyes. Has anyone ever tried reading code on an ebook reader? It seems like the e-ink would make it easy on the eyes, plus it would be portable, plus it wouldn't kill any trees. In other words, it sounds perfect, but before I drop a couple benjamins on an ebook reader, I'd like to hear if anyone else has tried this and how it went. It seems Scott Hanselman discussed using the Kindle to read code, but I wouldn't necessarily want a Kindle. Has anyone had a positive experience with some other device? I realize this is not directly about programming, but it relates directly to my ability to improve my skills. I think if a good portable reading device for code exists, it could help a lot of programmers.

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• git clone fails with "index-pack" failed?

  - by gct

  So I created a remote repo that's not bare (because I need redmine to be able to read it), and it's set to be shared with the group (so git init --shared=group). I was able to push to the remote repo and now I'm trying to clone it. If I clone it over the net I get this: remote: Counting objects: 4648, done. remote: Compressing objects: 100% (2837/2837), done. error: git-upload-pack: git-pack-objects died with error.B/s fatal: git-upload-pack: aborting due to possible repository corruption on the remote side. remote: aborting due to possible repository corruption on the remote side. fatal: early EOF fatal: index-pack failed I'm able to clone it locally without a problem, and I ran "git fsck", which only reports some dangling trees/blobs, which I understand aren't a problem. What could be causing this? I'm still able to pull from it, just not clone. I should note the remote git version is 1.5.6.5 while local is 1.6.0.4 I tried cloning my local copy of the repo, stripping out the .git folder and pushing to a new repo, then cloning the new repo and I get the same error, which leads me to believe it may be a file in the repo that's causing git-upload-pack to fail... Edit: I have a number of windows binaries in the repo, because I just built the python modules and then stuck them in there so everyone else didn't have to build them as well. If I remove the windows binaries and push to a new repo, I can clone again, perhaps that gives a clue. Trying to narrow down exactly what file is causing the problem now.

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• using compareTo in Binary Search Tree program

  - by Scott Rogener

  I've been working on this program for a few days now and I've implemented a few of the primary methods in my BinarySearchTree class such as insert and delete. Insert seemed to be working fine, but once I try to delete I kept getting errors. So after playing around with the code I wanted to test my compareTo methods. I created two new nodes and tried to compare them and I get this error: Exception in thread "main" java.lang.ClassCastException: TreeNode cannot be cast to java.lang.Integer at java.lang.Integer.compareTo(Unknown Source) at TreeNode.compareTo(TreeNode.java:16) at BinarySearchTree.myComparision(BinarySearchTree.java:177) at main.main(main.java:14) Here is my class for creating the nodes: public class TreeNode<T> implements Comparable { protected TreeNode<T> left, right; protected Object element; public TreeNode(Object obj) { element=obj; left=null; right=null; } public int compareTo(Object node) { return ((Comparable) this.element).compareTo(node); } } Am I doing the compareTo method all wrong? I would like to create trees that can handle integers and strings (seperatly of course)

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• PHP programmer wanting to learn Flash game development

  - by grokker

  Hi! I'm currently a PHP programmer and one of my childhood dreams is to create a game. A game to show my friends or my children when the time comes :) The problem is I don't know Flash. I'm not great at drawing stuff or even artistic. I could program a little with Javascript and I could consider myself intermediate with jQuery. So my question is, how do I get started? What books do I read first? What's the steps that I should take on this journey? Thank you SO friends. I hope you all could help me create something I could be proud of :) P.S. I'm just assuming that Flash is the easiest way to create and show to other people my game. Anyway I'm very open for other suggestions! My game in mind is a side scroller about an indiana jones type of character and the setting is on the jungle with trees and snakes and a lot of animals!

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• If Then Else Statement Condition Being Ignored?

  - by Matma

  I think im going mad but can some show me what im missing, it must be some stupidly simple i just cant see the wood for the trees. BOTH side of this if then else statement are being executed? Ive tried commenting out the true side and moving the condition to a seperate variable with the same result. However if i explicitly set the condition to 1=0 or 1=1 then the if then statement is operating as i would expect. i.e. only executing one side of the equation... The only time ive seen this sort of thing is when the compiler has crashed and is no longer compiling (without visible indication that its not) but ive restarted studio with the same results, ive cleaned the solution, built and rebuilt with no change? please show me the stupid mistake im making using vs2005 if it matters. Dim dset As DataSet = New DataSet If (CboCustomers.SelectedValue IsNot Nothing) AndAlso (CboCustomers.SelectedValue <> "") Then Dim Sql As String = "Select sal.SalesOrderNo As SalesOrder,cus.CustomerName,has.SerialNo, convert(varchar,sal.Dateofpurchase,103) as Date from [dbo].[Customer_Table] as cus " & _ " inner join [dbo].[Hasp_table] as has on has.CustomerID=cus.CustomerTag " & _ " inner join [dbo].[salesorder_table] as sal On sal.Hasp_ID =has.Hasp_ID Where cus.CustomerTag = '" & CboCustomers.SelectedValue.ToString & "'" Dim dap As SqlDataAdapter = New SqlDataAdapter(Sql, FormConnection) dap.Fill(dset, "dbo.Customer_Table") DGCustomer.DataSource = dset.Tables("dbo.Customer_Table") Else Dim erm As String = "wtf" End If

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• LINQ to Sql: Insert instead of Update

  - by Christina Mayers

  I am stuck with this problems for a long time now. Everything I try to do is insert a row in my DB if it's new information - if not update the existing one. I've updated many entities in my life before - but what's wrong with this code is beyond me (probably something pretty basic) I guess I can't see the wood for the trees... private Models.databaseDataContext db = new Models.databaseDataContext(); internal void StoreInformations(IEnumerable<EntityType> iEnumerable) { foreach (EntityType item in iEnumerable) { EntityType type = db.EntityType.Where(t => t.Room == item.Room).FirstOrDefault(); if (type == null) { db.EntityType.InsertOnSubmit(item); } else { type.Date = item.Date; type.LastUpdate = DateTime.Now(); type.End = item.End; } } } internal void Save() { db.SubmitChanges(); } Edit: just checked the ChangeSet, there are no updates only inserts. For now I've settled with foreach (EntityType item in iEnumerable) { EntityType type = db.EntityType.Where(t => t.Room == item.Room).FirstOrDefault(); if (type != null) { db.Exams.DeleteOnSubmit(type); } db.EntityType.InsertOnSubmit(item); } but I'd love to do updates and lose these unnecessary delete statements.

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• javascript innerHTML without childNodes?

  - by John Doe

  hi all im having a firefox issue where i dont see the wood for the trees using ajax i get html source from a php script this html code contains a tag and within the tbody some more tr/td's now i want to append this tbody plaincode to an existing table. but there is one more condition: the table is part of a form and thus contains checkboxe's and drop down's. if i would use table.innerHTML += content; firefox reloads the table and reset's all elements within it which isnt very userfriendly as id like to have what i have is this // content equals transport.responseText from ajax request function appendToTable(content){ var wrapper = document.createElement('table'); wrapper.innerHTML = content; wrapper.setAttribute('id', 'wrappid'); wrapper.style.display = 'none'; document.body.appendChild(wrapper); // get the parsed element - well it should be wrapper = document.getElementById('wrappid'); // the destination table table = document.getElementById('tableid'); // firebug prints a table element - seems right console.log(wrapper); // firebug prints the content ive inserted - seems right console.log(wrapper.innerHTML); var i = 0; // childNodes is iterated 2 times, both are textnode's // the second one seems to be a simple '\n' for(i=0;i<wrapper.childNodes.length;i++){ // firebug prints 'undefined' - wth!?? console.log(wrapper.childNodes[i].innerHTML); // firebug prints a textnode element - <TextNode textContent=" "> console.log(wrapper.childNodes[i]); table.appendChild(wrapper.childNodes[i]); } // WEIRD: firebug has no problems showing the 'wrappid' table and its contents in the html view - which seems there are the elements i want and not textelements } either this is so trivial that i dont see the problem OR its a corner case and i hope someone here has that much of expirience to give an advice on this - anyone can imagine why i get textnodes and not the finally parsed dom elements i expect? btw: btw i cant give a full example cause i cant write a smaller non working piece of code its one of those bugs that occure in the wild and not in my testset thx all

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• Is there a simple way to "roll your own forms" for mysql in php, for example in jquery?

  - by talkingnews

  I've been googling around for a really simple way of making what is, in effect, nothing more than an enhanced phpMySql. In a mysql database, I have: Name, address, phone, website etc, plus 2 or 3 custom fields. This data is pulled out to make a website. All I want is to be able to make a freeform form, a bit like Access, but for the web, and the only thing I want to do over and above normal field editing would be to have a list of when I contact them, what was said, and perhaps a reminder when the next action is due. I've looked at so many CRMs my mind is boggling, and they all do WAY more than I need. I don't have leads or accounts, all I have is the need to make sure than when I update the person's details, and for that data to be in the same DB as my site is generate from. I'm happy to learn if I can get pointed in the right direction, and I have a feeling that something like what I want might lie in the direction of jquery. It's just that there's so much good jquery stuff about, I can't see the wood for the trees! Thanks.

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• How to code a 'Next in Results' within search results in PHP

  - by thebluefox

  Right, bit of a head scratcher, although I've got a feeling there's an obvious answer and I'm just not seeing the wood for the trees. Baiscally, using Solr as a search engine for my site, bringing back 15 results per page. When you click on a result, you get a detail page, that has a "Next in Results" link on it, which obviously forwards you on to the next result. Whats the best way of doing this? I've come up with a few solutions but they're either too inpractical or just don't work. I could store all the ids in a session array, then grab the one after the current one and put that in the link. But with possibly hundreds/thousands of results, the memory that array would need, and the performance hit of dealing with it isn't practical. I could take the same approach and put it into the db, but I'll still have to deal with a potentially huge array when I grab them out of the db. Or; I could do the search again, only returning the id's, and grab the one after the one we're currently looking at. I think this could be the best option? Although it does seem kind of messy, namely because of when I have to select the id thats on a different 'page' (ie the 16th, 31st etc result). Unless I pass through where it was in the results, and select from there, but that still doesn't seem like the right way to do it. I'm really sorry if this is just complete nonsense, any help is massively appreciated as always, Cheers guys!

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• A dynamic array of a class, inside another separate class?

  - by pinnacler

  I'm working on a robot localization simulator and I created a class called "landmark". The end result is going to be a robot that is always centered and always faces the top of the screen. As it turns, the birds eye view map will rotate around the robot. To accomplish this, I'm assuming I can rotate one class and have all elements inside rotate as well. So, the landmark class has properties x,y, label, and radius. This is suppose to simulate a tree location in a forest. To test everything, I need "forest data," and I wrote a script to generate 100 trees in a 100m x 100m area. The script automatically generates values within an acceptable range for x,y, radius. The generated data is stored in an object called tempForest and is 100x3. Ideally, I want to create a class called "landmarks" (plural) that has 100 landmark instances inside. How would I instantiate 100 instances of landmark in one instance of landmarks using that randomly generated data? Ideally, I'd just type treeBeacons = landmarks(); and it would randomly populate 100 (user definable, set in config file) instances with x, y, radius data. I'm not sure how to deal with a dynamic array of class "Landmark", inside another single class "landmarks." Any ideas?

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• A feeling that I'm not that good developer

  - by Karim

  Hi, Im having a strange feeling, but let me first introduce myself as a software developer. I started to program when I was still a kid, I had about 10 or 11 years. I really enjoy my work and never get bored from it. It's amazing how somebody could be paid for what he really likes to do and would be doing it anyway even for free. WHen I first started to program, I was feeling proud of what I was doing, each application I built was for me a success and after 2-3 year I had a feeling that I'm a coding guru. It was a nice feeling ;-) But the more I was in the field, the more types of software I started to develop I was starting to have a feeling that I'm completely wrong in that I'm guru. I felt that I'm not even a mediocre developer. Each new field I start to work on is giving me this feeling. Like when I once developed a device driver for a client, I saw how much I need to learn about device drivers. When I developed a video filter for an application, I saw how much do I still need to learn about DirectShow, Color Spaces, and all the theory behind that. The worst thing was when I started to learn algorithms. It was several years ago. I knew then the basic structures and algorithms like the sorting, some types of trees, some hashtables, strings etc.. and when I really wanted to learn a group of structures I learned about 5-6 new types and saw that in fact even this small group has several hundred subtypes of structures. It's depressing how little time people have in their lives to learn all this stuff. I'm now a software developer with about 10 years of experience and I still feel that I'm not a proficient developer when I think about things that others do in the industry. Is this normal what I'm experiencing or is it a sign of a destructive excessive ambition? Thanks in advance for any comments.

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• Using ADO.NET Entities LINQ Provider to model complex SQL Queries?

  - by Ivan Zlatanov

  What I find really powerful in ADO.NET Entities or LINQ to SQL, is the ability to model complex queries. I really don't need the mappings that Entities or LINQ to SQL are doing for me - I just need the ability to model complex expressions that can be translated into T-SQL. My question is - am I abusing too much? Can I use the Entity Framework for modeling queries and just that? Should I? I know I can write my own custom LINQ to SQL provider, but that is just not possible to handle in the time spans I have. What is the best approach to model complex T-SQL queries? How do you handle conditional group byes, orders, joins, unions etc in the OOP world? Using StringBuilders for this kind of job feels too ugly and harder to maintain given the possibilities we have with Expression Trees. When I use StringBuilder to model a complex SQL Query I feel kind of guilty! I feel the same way as when I have to hard code any number into my code that is different than 0 or 1. Feeling that makes you ask yourself if there is a better and cleaner way of doing it... I must mention that I am using C# 4.0, but I am not specifically looking for an answer in this language, but rather in the domain of CLR 4.

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• Matlab matrix translation and rotation multiple times

  - by pinnacler

  I have a map of individual trees from a forest stored as x,y points in a matrix. I call it fixedPositions. It's cartesian and (0,0) is the origin. I would like 0/360 degrees to be the top of the screen and 90 degrees to be to the right. Given a velocity and a heading, i.e. .5 m/s and 60 degrees (2 o'clock equivalent on a watch), how do I rotate that x,y points, so that the new origin is centered at (.5cos(60),.5sin(60)) and 60 degrees is now at the top of the screen? Then if I were to give you another heading and speed, i.e. 0 degrees and 2m/s, it should calculate it from the last point, not the original fixedPositions origin. I've wasted my day trying to figure this out. I wish I took matrix algebra but I'm at a loss. I tried doing cos(30) and even those wouldn't compute correctly, which after an hour I realize were in radians.

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• Permuting a binary tree without the use of lists

  - by Banang

  I need to find an algorithm for generating every possible permutation of a binary tree, and need to do so without using lists (this is because the tree itself carries semantics and restraints that cannot be translated into lists). I've found an algorithm that works for trees with the height of three or less, but whenever I get to greater hights, I loose one set of possible permutations per height added. Each node carries information about its original state, so that one node can determine if all possible permutations have been tried for that node. Also, the node carries information on weather or not it's been 'swapped', i.e. if it has seen all possible permutations of it's subtree. The tree is left-centered, meaning that the right node should always (except in some cases that I don't need to cover for this algorithm) be a leaf node, while the left node is always either a leaf or a branch. The algorithm I'm using at the moment can be described sort of like this: if the left child node has been swapped swap my right node with the left child nodes right node set the left child node as 'unswapped' if the current node is back to its original state swap my right node with the lowest left nodes' right node swap the lowest left nodes two childnodes set my left node as 'unswapped' set my left chilnode to use this as it's original state set this node as swapped return null return this; else if the left child has not been swapped if the result of trying to permute left child is null return the permutation of this node else return the permutation of the left child node if this node has a left node and a right node that are both leaves swap them set this node to be 'swapped' The desired behaviour of the algoritm would be something like this: branch / | branch 3 / | branch 2 / | 0 1 branch / | branch 3 / | branch 2 / | 1 0 <-- first swap branch / | branch 3 / | branch 1 <-- second swap / | 2 0 branch / | branch 3 / | branch 1 / | 0 2 <-- third swap branch / | branch 3 / | branch 0 <-- fourth swap / | 1 2 and so on... Sorry for the ridiculisly long and waddly explanation, would really, really apreciate any sort of help you guys could offer me. Thanks a bunch!

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• Why can't RB-Tree be a list?

  - by Alex

  Hey everyone. I have a problem with the rb-trees. according to wikipedia, rb-tree needs to follow the following: A node is either red or black. The root is black. (This rule is used in some definitions and not others. Since the root can always be changed from red to black but not necessarily vice-versa this rule has little effect on analysis.) All leaves are black. Both children of every red node are black. Every simple path from a given node to any of its descendant leaves contains the same number of black nodes. As we know, an rb-tree needs to be balanced and has the height of O(log(n)). But, if we insert an increasing series of numbers (1,2,3,4,5...) and theoretically we will get a tree that will look like a list and will have the height of O(n) with all its nodes black, which doesn't contradict the rb-tree properties mentioned above. So, where am I wrong?? thanks.

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• Generics vs inheritance (when no collection classes are involved)

  - by Ram

  This is an extension of this questionand probably might even be a duplicate of some other question(If so, please forgive me). I see from MSDN that generics are usually used with collections The most common use for generic classes is with collections like linked lists, hash tables, stacks, queues, trees and so on where operations such as adding and removing items from the collection are performed in much the same way regardless of the type of data being stored. The examples I have seen also validate the above statement. Can someone give a valid use of generics in a real-life scenario which does not involve any collections ? Pedantically, I was thinking about making an example which does not involve collections public class Animal<T> { public void Speak() { Console.WriteLine("I am an Animal and my type is " + typeof(T).ToString()); } public void Eat() { //Eat food } } public class Dog { public void WhoAmI() { Console.WriteLine(this.GetType().ToString()); } } and "An Animal of type Dog" will be Animal<Dog> magic = new Animal<Dog>(); It is entirely possible to have Dog getting inherited from Animal (Assuming a non-generic version of Animal)Dog:Animal Therefore Dog is an Animal Another example I was thinking was a BankAccount. It can be BankAccount<Checking>,BankAccount<Savings>. This can very well be Checking:BankAccount and Savings:BankAccount. Are there any best practices to determine if we should go with generics or with inheritance ?

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• Sharing same vector control between different places

  - by Alexander K

  Hi everyone, I'm trying to implement the following: I have an Items Manager, that has an Item class inside. Item class can store two possible visual representations of it - BitmapImage(bitmap) and UserControl(vector). Then later, in the game, I need to share the same image or vector control between all possible places it takes place. For example, consider 10 trees on the map, and all point to the same vector control. Or in some cases this can be bitmap image source. So, the problem is that BitmapImage source can be easily shared in the application by multiple UIElements. However, when I try to share vector control, it fails, and says Child Element is already a Child element of another control. I want to know how to organize this in the best way. For example replace UserControl with other type of control, or storage, however I need to be sure it supports Storyboard animations inside. The code looks like this: if (bi.item.BitmapSource != null) { Image previewImage = new Image(); previewImage.Source = bi.item.BitmapSource; itemPane.ItemPreviewCanvas.Children.Add(previewImage); } else if (bi.item.VectorSource != null) { UserControl previewControl = bi.item.VectorSource; itemPane.ItemPreviewCanvas.Children.Add(previewControl); } Thanks in advance

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• WPF tree data binding model & repository

  - by Am

  Hi, I have a well defined tree repository. Where I can rename items, move them up, down, etc. Add new and delete. The data is stored in a table as follows: Index Parent Label Left Right 1 0 root 1 14 2 1 food 2 7 3 2 cake 3 4 4 2 pie 5 6 5 1 flowers 8 13 6 5 roses 9 10 7 5 violets 11 12 Representing the following tree: (1) root (14) (2) food (7) (8) flowers (13) (3) cake (4) (5) pie (6) (9) roeses (10) (11) violets (12) or root food cake pie flowers roses violets Now, my problem is how to represent this in a bindable way, so that a TreeView can handle all the possible data changes? Renaming is easy, all I need is to make the label an updatble field. But what if a user moves flowers above food? I can make the relevant data changes, but they cause a complete data change to all other items in the tree. And all the examples I found of bindable hierarchies are good for non static trees.. So my current (and bad) solution is to reload the displayed tree after relocation change. Any direction will be good. Thanks

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