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  • JSF2.0: variable list of custom component

    - by rattaman
    Hello Is there any way of using JSF2.0 in connection with variable lists of components? For example, lets say I have list o people that I would like to edit. They are presented on the page as list of components PersonEditor, which allow changing person data. Each editor is associated with single Person element. In order for this to work I need to perform following steps: On initial request: Get list of people For each person create PersonEditor and associate it with Person object. Fill editor's data. On user action: When user changes values and presses Save, data is processed by backing bean. I can either fill editor with data from list of people or bind it to the backing bean, but not at the same time, so I am stuck. I tried people.xhtml <ui:render value="#{bean.people}" var="person"> <example:personEditor person="#{person}"/> </ui:render> where personEditor.xhtml: a) proper association with person object, but no connection to backing bean <h:form> <h:outputText value="#{cc.attr.person.name}"/> <h:commandButton name="Save" actionListener="editorBean.save"> <f:ajax execute="@form" render="@form"/> </h:commandButton> </h:form> b) no association with person object, but there is connection to backing bean - there is no way to pass that person to the backing bean <h:form> <h:outputText value="#{editorBean.name}"/> <h:commandButton name="Save" actionListener="editorBean.save"> <f:ajax execute="@form" render="@form"/> </h:commandButton> </h:form> If I had each editor on separate page, I could pass the person id as url parameter (either using f:param or f:attribute) and initialize it accordingly. Is there any solution to this problem?

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  • C# Dataset Dynamically Add DataColumn

    - by Wesley
    I am trying to add a extra column to a dataset after a query has completed. I have a database relationship of the following: Employees / \ Groups EmployeeGroups Empoyees holds all the data for that individual, I'll name the unique key the UserID. Groups holds all the groups that a employee can be a part of, i.e. Super User, Admin, User; etc. I will name the unique key GroupID EmployeeGroups holds all the associations of which groups each employee belongs too. (UserID | GroupID) What I am trying to accomplish is after querying for a all users I want to loop though each user and add what groups that user is a part of by adding a new column to the dataset named 'Groups' which is a string to insert the values of the next query to get all the groups that user is a part of. Then by user of databinding populate a listview with all employees and their group associations My code is as follows; Position 5 is the new column I am trying to add to the dataset. string theQuery = "select UserID, FirstName, LastName, EmployeeID, Active from Employees"; DataSet theEmployeeSet = itsDatabase.runQuery(theQuery); DataColumn theCol = new DataColumn("Groups", typeof(string)); theEmployeeSet.Tables[0].Columns.Add(theCol); foreach (DataRow theRow in theEmployeeSet.Tables[0].Rows) { theRow.ItemArray[5] = "1234"; } At the moment, the code will create the new column but when i assign the data to that column nothing will be assigned, what am I missing? If there is any further explination or information I can provide, please let me know. Thank you all

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  • ColdFusion Session issue - multiple users behind one proxy IP -- cftoken and cfid seems to be shared

    - by smoothoperator
    Hi Everyone, I have an application that uses coldfusion's session management (instead of the J2EE) session management. We have one client, who has recently switched their company's traffic to us to come viaa proxy server in their network. So, to our Coldfusion server, it appears that all traffic is coming from this one IP Address, for all of the accounts of this one company.. Of the session variables, Part 1 is kept in a cflock, and Part 2 is kept in editable session variables. I may be misundestanding, but we have done it this way as we modify some values as needed throughout the application's usage. We are now running into an issue of this client having their session variables mixed up (?). We have one case where we set a timestamp.. and when it comes time to look it up, it's empty. From the looks of it this is happening because of another user on the same token. My initial thoughts are to look into modifying our existing session management to somehow generate a unique cftoken/cfid, or to start using jsession_ID, if this solves the problem at all. I have done some basic research on this issue and couldn't find anything similar, so I thought I'd ask here. Thanks!

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  • Segmentation Fault?

    - by user336808
    Hello, when I run this program while inputting a number greater than 46348, I get a segmentation fault. For any values below it, the program works perfectly. I am using CodeBlocks 8.02 on Ubuntu 10.04 64-bit. The code is as follows: int main() { int number = 46348; vector<bool> sieve(number+1,false); vector<int> primes; sieve[0] = true; sieve[1] = true; for(int i = 2; i <= number; i++) { if(sieve[i]==false) { primes.push_back(i); int temp = i*i; while(temp <= number) { sieve[temp] = true; temp = temp + i; } } } for(int i = 0; i < primes.size(); i++) cout << primes[i] << " "; return 0; }

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  • Best practices for encrypting continuous/small UDP data

    - by temp
    Hello everyone, I am having an application where I have to send several small data per second through the network using UDP. The application need to send the data in real-time (no waiting). I want to encrypt these data and insure that what I am doing is as secure as possible. Since I am using UDP, there is no way to use SSL/TLS, so I have to encrypt each packet alone since the protocol is connectionless/unreliable/unregulated. Right now, I am using a 128-bit key derived from a passphrase from the user, and AES in CBC mode (PBE using AES-CBC). I decided to use a random salt with the passphrase to derive the 128-bit key (prevent dictionary attack on the passphrase), and of course use IVs (to prevent statistical analysis for packets). However I am concerned about few things: Each packet contains small amount of data (like a couple of integer values per packet) which will make the encrypted packets vulnerable to known-plaintext attacks (which will result in making it easier to crack the key). Also, since the encryption key is derived from a passphrase, this will make the key space way less (I know the salt will help, but I have to send the salt through the network once and anyone can get it). Given these two things, anyone can sniff and store the sent data, and try to crack the key. Although this process might take some time, once the key is cracked all the stored data will be decrypted, which will be a real problem for my application. So my question is, what is the best practices for sending/encrypting continuous small data using a connectionless protocol (UDP)? Is my way the best way to do it? ...flowed? ...Overkill? ... Please note that I am not asking for a 100% secure solution, as there is no such thing. Cheers

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  • Alternatives to static methods on interfaces for enforcing consistency

    - by jayshao
    In Java, I'd like to be able to define marker interfaces, that forced implementations to provide static methods. For example, for simple text-serialization/deserialization I'd like to be able to define an interface that looked something like this: public interface TextTransformable<T>{ public static T fromText(String text); public String toText(); Since interfaces in Java can't contain static methods though (as noted in a number of other posts/threads: here, here, and here this code doesn't work. What I'm looking for however is some reasonable paradigm to express the same intent, namely symmetric methods, one of which is static, and enforced by the compiler. Right now the best we can come up with is some kind of static factory object or generic factory, neither of which is really satisfactory. Note: in our case our primary use-case is we have many, many "value-object" types - enums, or other objects that have a limited number of values, typically carry no state beyond their value, and which we parse/de-parse thousands of time a second, so actually do care about reusing instances (like Float, Integer, etc.) and its impact on memory consumption/g.c. Any thoughts?

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  • EditText items in a scrolling list lose their changes when scrolled off the screen

    - by ianww
    I have a long scrolling list of EditText items created by a SimpleCursorAdapter and prepopulated with values from an SQLite database. I make this by: cursor = db.rawQuery("SELECT _id, criterion, localweight, globalweight FROM " + dbTableName + " ORDER BY criterion", null); startManagingCursor(cursor); mAdapter = new SimpleCursorAdapter(this, R.layout.weight_edit_items, cursor, new String[]{"criterion","localweight","globalweight"}, new int[]{R.id.criterion_edit, R.id.localweight_edit, R.id.globalweight_edit}); this.setListAdapter(mAdapter); The scrolling list is several emulator screens long. The items display OK - scrolling through them shows that each has the correct value from the database. I can make an edit change to any of the EditTexts and the new text is accepted and displayed in the box. But...if I then scroll the list far enough to take the edited item off the screen, when I scroll back to look at it again its value has returned to what it was before I made the changes, ie. my edits have been lost. In trying to sort this out, I've done a getText to look at what's in the EditText after I've done my edits (and before a scroll) and getText returns the original text, even though the EditText is displaying my new text. It seems that the EditText has only accepted my edits superficially and they haven't been bound to the EditText, meaning they get dropped when scrolled off the screen. Can anyone please tell me what's going on here and what I need to do to force the EditText to retain its edits? Thanks Ian

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  • Are there equivalents to Ruby's method_missing in other languages?

    - by Justin Ethier
    In Ruby, objects have a handy method called method_missing which allows one to handle method calls for methods that have not even been (explicitly) defined: Invoked by Ruby when obj is sent a message it cannot handle. symbol is the symbol for the method called, and args are any arguments that were passed to it. By default, the interpreter raises an error when this method is called. However, it is possible to override the method to provide more dynamic behavior. The example below creates a class Roman, which responds to methods with names consisting of roman numerals, returning the corresponding integer values. class Roman def romanToInt(str) # ... end def method_missing(methId) str = methId.id2name romanToInt(str) end end r = Roman.new r.iv #=> 4 r.xxiii #=> 23 r.mm #=> 2000 For example, Ruby on Rails uses this to allow calls to methods such as find_by_my_column_name. My question is, what other languages support an equivalent to method_missing, and how do you implement the equivalent in your code?

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  • How do I restart mysql and where is my.cnf file

    - by dorelal
    I am using snow leopard mac. I installed mysql on my machine using instructions mentioned here. Everything works great. However I have two questions. 1) Where is my.cnf file? I searched the whole file system and result is empty. Is it possible that there is no my.cnf and mysql works with default values. If yes then probably I should create my.inf at /etc/mysql. Is that right? 2) How do I restar server. I know it gets started when I restart my machine. Here is what plist looks like. mysqld_safe does not let me restart server. <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>KeepAlive</key> <true/> <key>Label</key> <string>com.mysql.mysqld</string> <key>Program</key> <string>/usr/local/mysql/bin/mysqld_safe</string> <key>RunAtLoad</key> <true/> <key>UserName</key> <string>mysql</string> <key>WorkingDirectory</key> <string>/usr/local/mysql</string> </dict> </plist>

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  • algorithm - How to sort a 0/1 array with 2n/3 comparisons?

    - by Jackson Tale
    In Algorithm Design Manual, there is such an excise 4-26 Consider the problem of sorting a sequence of n 0’s and 1’s using comparisons. For each comparison of two values x and y, the algorithm learns which of x < y, x = y, or x y holds. (a) Give an algorithm to sort in n - 1 comparisons in the worst case. Show that your algorithm is optimal. (b) Give an algorithm to sort in 2n/3 comparisons in the average case (assuming each of the n inputs is 0 or 1 with equal probability). Show that your algorithm is optimal. For (a), I think it is fairly easy. I can choose a[n-1] as pivot, then do something like in quicksort partition, scan 0 to n - 2, find the middle point where left side is all 0 and right side is all 1, this take n - 1 comparisons. But for (b), I can't get a clue. It says "each of the n inputs is 0 or 1 with equal probability", so I guess I can assume the numbers of 0 and 1 equal? But how can I get a result which is related to 1/3? divide the whole array into 3 groups? Thanks

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  • Deserialize xml which uses attribute name/value pairs

    - by Bodyloss
    My application receives a constant stream of xml files which are more or less a direct copy of the database record <record type="update"> <field name="id">987654321</field> <field name="user_id">4321</field> <field name="updated">2011-11-24 13:43:23</field> </record> And I need to deserialize this into a class which provides nullable property's for all columns class Record { public long? Id { get; set; } public long? UserId { get; set; } public DateTime? Updated { get; set; } } I just cant seem to work out a method of doing this without having to parse the xml file manually and switch on the field's name attribute to store the values. Is their a way this can be achieved quickly using an XmlSerializer? And if not is their a more efficient way of parsing it manually? Regards and thanks My main problem is that the attribute name needs to have its value set to a property name and its value as the contents of a <field>..</field> element

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  • NHibernate mapping with two special cases

    - by brainimus
    I am using NHibernate to map a class to a database table. The Part table has an ID column (primary key) and a ParentPart column (along with a few others). class Part { public virtual long ID{ get; set; } public virtual Part ParentPart { get; set; } } The ParentPart is normally another valid part in the part table but I have two special cases. I have a case where the ParentPart column can be 0 (zero) and another case where it can be -1. Neither of these cases currently represent another valid Part object. I was thinking I could make 2 subclasses of Part (ZeroPart and NegativeOnePart) that would never persist. I want the zero and -1 values to be entered in the column but not persist the entire ZeroPart or NegativeOnePart objects. I am unsure how to map this (I'm using hbm files) or if this even the correct approach. How can I map this so that normal valid parts are persisted but I can also handle the special cases? As an aside: My current hbm file has the Part.ID's unsaved value as zero but I think I can just change this in the mapping to something different and default it in the class.

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  • xml parser not able to read all the nodes of the xml

    - by pankaj
    Hi i am trying to get values from all the nodes of a xml returned from a web service. But my code only reads first node, it does not read it further. code: -(void)parseData{ NuanceAppDelegate *appDel = (NuanceAppDelegate *)[[UIApplication sharedApplication] delegate]; NSString *url = @"http://cmweb.bpomatrix.net/SmartPhoneService.svc/login/"; url = [[[url stringByAppendingString:UserName] stringByAppendingString:@"/"] stringByAppendingString:Password]; url = [[url stringByAppendingString:@"/"] stringByAppendingString:appDel.CPAID]; NSLog(@"log: @%",url); NSURL *loginURL = [NSURL URLWithString:url]; NSXMLParser *home_Parser = [[NSXMLParser alloc] initWithContentsOfURL:loginURL]; [home_Parser setDelegate:self]; dict = [[NSMutableDictionary alloc] init]; [home_Parser parse]; } - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict{ if([elementName isEqualToString:@"Address"]) addressFound = TRUE; if([elementName isEqualToString:@"Name"]) nameFound = TRUE; if([elementName isEqualToString:@"LoyaltyNum"]) loyaltyNumFound = TRUE; if([elementName isEqualToString:@"City"]) cityFound = TRUE; if([elementName isEqualToString:@"Province"]) proFound = TRUE; if([elementName isEqualToString:@"Zip"]) zipFound = TRUE; //NSLog(@"Response %@",responseFound); } - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{ if(addressFound) { [dict setObject:string forKey:@"address"]; addressFound = FALSE; } else if(nameFound) { [dict setObject:string forKey:@"name"]; nameFound = FALSE; } else if(loyaltyNumFound) { [dict setObject:string forKey:@"loyaltyNum"]; loyaltyNumFound = FALSE; } else if(cityFound) { [dict setObject:string forKey:@"city"]; cityFound = FALSE; } else if(proFound) { [dict setObject:string forKey:@"province"]; proFound = FALSE; } else if(zipFound) { [dict setObject:string forKey:@"zip"]; zipFound = FALSE; } } - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName { if([elementName isEqualToString:@"clsUserProfile"]) { [self parsingOver]; } } -(void)parsingOver { NuanceAppDelegate *appDel = (NuanceAppDelegate *)[[UIApplication sharedApplication] delegate]; appDel.dictProfile = dict; }

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  • Validating a value for a DataColumn

    - by Richard Neil Ilagan
    Hello! I'm using a DataGrid with edit functionalities in my project. It's handy, compared to having to edit its source data manually, but sadly, that means that I'll have to deal with validating user input a bit more. And my problem is basically just that. When I set my DataGrid to EDIT mode, modify the values and then set it to UPDATE, what is the best way to check if a value that I've entered is, in fact, compatible with the corresponding column's data type? i.e. (simple example) // assuming DataTable dt = new DataTable(); dt.Columns.Add("aa",typeof(System.Int32)); DataGrid dg = new DataGrid(); dg.DataSource = dt; dg.DataBind(); dg.UpdateCommand += dg_Update; // this is the update handler protected void dg_Update(object src, DataGridCommandEventArgs e) { string newValue = (someValueIEnteredInTextBox); // HOW DO I CHECK IF [newValue] IS COMPATIBLE WITH COLUMN "aa" ABOVE? dt.LoadDataRow(newValue, true); } Thanks guys. Any leads would be so much help.

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  • Calling a WPF Application and modify exposed properties?

    - by Justin
    I have a WPF Keyboard Application, it is developed in such a way that an application could call it and modify its properties to adapt the Keyboard to do what it needs to. Right now I have a file *.Keys.Set which tells the application (on open) to style itself according to that new style. I know this file could be passed as a command line argument into the application. That would not be a problem. My concern is, is there a way via a managed environment to change the properties of the executable as long as they are exposed properly, an example: 'Creates a new instance of the Keyboard Application Dim e_key as new WpfApplication("C:\egt\components\keyboard.exe") 'Sets the style path e_key.SetStylePath("c:\users\joe\apps\me\default.keys.set") e_key.Refresh() 'Applies the style e_key.HideMenu() 'Hides the menu e_key.ShowDeck("PIN") 'Shows the custom "deck" of keyboard keys the developer 'Created in the style application. ''work with events and response 'Clear the instance from memory e_key.close e_key.dispose e_key = nothing This would allow my application to become easily accessible to other Touch Screen Application Developers, allowing them to use my keyboard and keep the functionality they need. It seems like it might be possible because (name of executable).application shows all the exposed functions, properties, and values. I just have never done this before. Any help would be appreciated, thank you in advance.

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  • Calculating a consecutive streak in data

    - by Jura25
    I’m trying to calculate the maximum winning and losing streak in a dataset (i.e. the highest number of consecutive positive or negative values). I’ve found a somewhat related question here on StackOverflow and even though that gave me some good suggestions, the angle of that question is different, and I’m not (yet) experienced enough to translate and apply that information to this problem. So I was hoping you could help me out, even an suggestion would be great. My data set look like this: > subRes Instrument TradeResult.Currency. 1 JPM -3 2 JPM 264 3 JPM 284 4 JPM 69 5 JPM 283 6 JPM -219 7 JPM -91 8 JPM 165 9 JPM -35 10 JPM -294 11 KFT -8 12 KFT -48 13 KFT 125 14 KFT -150 15 KFT -206 16 KFT 107 17 KFT 107 18 KFT 56 19 KFT -26 20 KFT 189 > split(subRes[,2],subRes[,1]) $JPM [1] -3 264 284 69 283 -219 -91 165 -35 -294 $KFT [1] -8 -48 125 -150 -206 107 107 56 -26 189 In this case, the maximum (winning) streak for JPM is four (namely the 264, 284, 69 and 283 consecutive positive results) and for KFT this value is 3 (107, 107, 56). My goal is to create a function which gives the maximum winning streaks per instrument (i.e. JPM: 4, KFT: 3). To achieve that: R needs to compare the current result with the previous result, and if it is higher then there is a streak of at least 2 consecutive positive results. Then R needs to look at the next value, and if this is also higher: add 1 to the already found value of 2. If this value isn’t higher, R needs to move on to the next value, while remembering 2 as the intermediate maximum. I’ve tried cumsum and cummax in accordance with conditional summing (like cumsum(c(TRUE, diff(subRes[,2]) > 0))), which didn’t work out. Also rle in accordance with lapply (like lapply(rle(subRes$TradeResult.Currency.), function(x) diff(x) > 0)) didn’t work. How can I make this work?

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  • Model class for NSDictionary information with Lazy Loading

    - by samfu_1
    My application utilizes approx. 50+ .plists that are used as NSDictionaries. Several of my view controllers need access to the properties of the dictionaries, so instead of writing duplicate code to retrieve the .plist, convert the values to a dictionary, etc, each time I need the info, I thought a model class to hold the data and supply information would be appropriate. The application isn't very large, but it does handle a good deal of data. I'm not as skilled in writing model classes that conform to the MVC paradigm, and I'm looking for some strategies for this implementation that also supports lazy loading.. This model class should serve to supply data to any view controller that needs it and perform operations on the data (such as adding entries to dictionaries) when requested by the controller functions currently planned: returning the count on any dictionary adding one or more dictionaries together Currently, I have this method for supporting the count lookup for any dictionary. Would this be an example of lazy loading? -(NSInteger)countForDictionary: (NSString *)nameOfDictionary { NSBundle *bundle = [NSBundle mainBundle]; NSString *plistPath = [bundle pathForResource: nameOfDictionary ofType: @"plist"]; //load plist into dictionary NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] initWithContentsOfFile: plistPath]; NSInteger count = [dictionary count] [dictionary release]; [return count] }

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  • How can I timeout Client-scoped variables in Coldfusion?

    - by Joshua Carmody
    I apologize if this is a "duh" question. It seems like the answer should be easily googleable, but I haven't found it yet. I am working on a large Coldfusion application that stores a large amount of session/user data in the Client scope (ie <cfset Client.UserName = "JoshuaC"> ). I did not write this application, and I don't have the luxury of significantly refactoring it. I've been given the task of setting the Client variables to time out after 72 hours. I'm not entirely sure how to do this. If I had written the application, I would have stored the variables in the Session scope, and then changed the sessiontimeout attribute of the CFAPPLICATION tag. As it is though, I'm not sure if that timeout affects the Client variables, or what their level of persistence is. The way the application works now, the Client variables never time out, and only clearing the user's cookies, or visiting a logout page which sets all the Client-scoped application variables to "", will clear the values. Of course, I could create some kind of timestamp variable like Client.LastAccessDateTime, and put something in the Application.cfm to clear the client variables if that datetime is more than 72 hours prior to Now(). But there's got to be a better way, right?

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  • C# Retrieving Data From XML File

    - by Christopher MacKinnon
    I seem to be having a problem with retrieving XML values with C#, which I know it is due to my very limited knowledge of C# and .XML. I was given the following XML file <PowerBuilderRunTimes> <PowerBuilderRunTime> <Version>12</Version> <Files> <File>EasySoap110.dll</File> <File>exPat110.dll</File> <File>pbacc110.dll</File> </File> </PowerBuilderRunTime> </PowerBuilderRunTimes> I am to process the XML file and make sure that each of the files in the exist in the folder (that's the easy part). It's the processing of the XML file that I have having a hard time with. Here is what I have done thus far: var runtimeXml = File.ReadAllText(string.Format("{0}\\{1}", configPath, Resource.PBRuntimes)); var doc = XDocument.Parse(runtimeXml); var topElement = doc.Element("PowerBuilderRunTimes"); var elements = topElement.Elements("PowerBuilderRunTime"); foreach (XElement section in elements) { //pbVersion is grabbed earlier. It is the version of PowerBuilder if( section.Element("Version").Value.Equals(string.Format("{0}", pbVersion ) ) ) { var files = section.Elements("Files"); var fileList = new List<string>(); foreach (XElement area in files) { fileList.Add(area.Element("File").Value); } } } My issue is that the String List is only ever populated with one value, "EasySoap110.dll", and everything else is ignored. Can someone please help me, as I am at a loss.

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  • How to use two parameters pointing to the same structure in one function ?

    - by ZaZu
    Hey guys, I have my code below that consits of a structure, a main, and a function. The function is supposed to display two parameters that have certain values, both of which point to the same structure. The problem I dont know how to add the SECOND parameter onto the following code : #include<stdio.h> #define first 500 #define sec 500 struct trial{ int f; int r; float what[first][sec]; }; int trialtest(trial *test); main(){ trial test; trialtest(&test); } int trialtest(trial *test){ int z,x,i; for(i=0;i<5;i++){ printf("%f,(*test).what[z][x]); } return 0; } I need to add a new parameter test_2 there (IN THE SAME FUNCTION) using this code : for(i=0;i<5;i++){ printf("%f,(*test_2).what[z][x]); How does int trialtest(trial *test) changes ? and how does it change in main ? I know that I should declare test_2 as well, like this : trial test,test_2; But what about passing the address in the function ? I do not need to edit it right ? trialtest(&test); --- This will remain the same ? So please, tell me how would I use test_2 as a parameter pointing to the same structure as test, both in the same function.. Thank you !! Please tell me if you need more clarification

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  • R: Are there any alternatives to loops for subsetting from an optimization standpoint?

    - by Adam
    A recurring analysis paradigm I encounter in my research is the need to subset based on all different group id values, performing statistical analysis on each group in turn, and putting the results in an output matrix for further processing/summarizing. How I typically do this in R is something like the following: data.mat <- read.csv("...") groupids <- unique(data.mat$ID) #Assume there are then 100 unique groups results <- matrix(rep("NA",300),ncol=3,nrow=100) for(i in 1:100) { tempmat <- subset(data.mat,ID==groupids[i]) #Run various stats on tempmat (correlations, regressions, etc), checking to #make sure this specific group doesn't have NAs in the variables I'm using #and assign results to x, y, and z, for example. results[i,1] <- x results[i,2] <- y results[i,3] <- z } This ends up working for me, but depending on the size of the data and the number of groups I'm working with, this can take up to three days. Besides branching out into parallel processing, is there any "trick" for making something like this run faster? For instance, converting the loops into something else (something like an apply with a function containing the stats I want to run inside the loop), or eliminating the need to actually assign the subset of data to a variable?

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  • Use properties or methods to expose business rules in C#?

    - by Val
    I'm writing a class to encapsulate some business rules, each of which is represented by a boolean value. The class will be used in processing an InfoPath form, so the rules get the current program state by looking up values in a global XML data structure using XPath operations. What's the best (most idiomatic) way to expose these rules to callers -- properties or public methods? Call using properties Rules rules = new Rules(); if ( rules.ProjectRequiresApproval ) { // get approval } else { // skip approval } Call using methods Rules rules = new Rules(); if ( rules.ProjectRequiresApproval() ) { // get approval } else { // skip approval } Rules class exposing rules as properties public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule property public bool ProjectRequiresApproval { get { return _amount < threshold } } } Rules class exposing rules as methods public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule method public bool ProjectRequiresApproval() { return _amount < threshold; } } What are the pros and cons of one over the other?

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  • Why do I get errors when using unsigned integers in an expression with C++?

    - by neuviemeporte
    Given the following piece of (pseudo-C++) code: float x=100, a=0.1; unsigned int height = 63, width = 63; unsigned int hw=31; for (int row=0; row < height; ++row) { for (int col=0; col < width; ++col) { float foo = x + col - hw + a * (col - hw); cout << foo << " "; } cout << endl; } The values of foo are screwed up for half of the array, in places where (col - hw) is negative. I figured because col is int and comes first, that this part of the expression is converted to int and becomes negative. Unfortunately, apparently it doesn't, I get an overflow of an unsigned value and I've no idea why. How should I resolve this problem? Use casts for the whole or part of the expression? What type of casts (C-style or static_cast<...)? Is there any overhead to using casts (I need this to work fast!)? EDIT: I changed all my unsigned ints to regular ones, but I'm still wondering why I got that overflow in this situation.

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  • Converting contents of a byte array to wchar_t*

    - by Christopher MacKinnon
    I seem to be having an issue converting a byte array (containing the text from a word document) to a LPTSTR (wchar_t *) object. Every time the code executes, I am getting a bunch of unwanted Unicode characters returned. I figure it is because I am not making the proper calls somewhere, or not using the variables properly, but not quite sure how to approach this. Hopefully someone here can guide me in the right direction. The first thing that happens in we call into C# code to open up Microsoft Word and convert the text in the document into a byte array. byte document __gc[]; document = word->ConvertToArray(filename); The contents of document are as follows: {84, 101, 115, 116, 32, 68, 111, 99, 117, 109, 101, 110, 116, 13, 10} Which ends up being the following string: "Test Document". Our next step is to allocate the memory to store the byte array into a LPTSTR variable, byte __pin * value; value = &document[0]; LPTSTR image; image = (LPTSTR)malloc( document->Length + 1 ); Once we execute the line where we start allocating the memory, our image variable gets filled with a bunch of unwanted Unicode characters: ????????????????? And then we do a memcpy to transfer over all of the data memcpy(image,value,document->Length); Which just causes more unwanted Unicode characters to appear: ????????????????? I figure the issue that we are having is either related to how we are storing the values in the byte array, or possibly when we are copying the data from the byte array to the LPTSTR variable. Any help with explaining what I'm doing wrong, or anything to point me in the right direction will be greatly appreciated.

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  • Building static (but complicated) lookup table using templates.

    - by MarkD
    I am currently in the process of optimizing a numerical analysis code. Within the code, there is a 200x150 element lookup table (currently a static std::vector < std::vector < double ) that is constructed at the beginning of every run. The construction of the lookup table is actually quite complex- the values in the lookup table are constructed using an iterative secant method on a complicated set of equations. Currently, for a simulation, the construction of the lookup table is 20% of the run time (run times are on the order of 25 second, lookup table construction takes 5 seconds). While 5-seconds might not seem to be a lot, when running our MC simulations, where we are running 50k+ simulations, it suddenly becomes a big chunk of time. Along with some other ideas, one thing that has been floated- can we construct this lookup table using templates at compile time? The table itself never changes. Hard-coding a large array isn't a maintainable solution (the equations that go into generating the table are constantly being tweaked), but it seems that if the table can be generated at compile time, it would give us the best of both worlds (easily maintainable, no overhead during runtime). So, I propose the following (much simplified) scenario. Lets say you wanted to generate a static array (use whatever container suits you best- 2D c array, vector of vectors, etc..) at compile time. You have a function defined- double f(int row, int col); where the return value is the entry in the table, row is the lookup table row, and col is the lookup table column. Is it possible to generate this static array at compile time using templates, and how?

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