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  • Help understanding .NET delegates, events, and eventhandlers

    - by Seth Spearman
    Hello, In the last couple of days I asked a couple of questions about delegates HERE and HERE. I confess...I don't really understand delegates. And I REALLY REALLY REALLY want to understand and master them. (I can define them--type safe function pointers--but since I have little experience with C type languages it is not really helpful.) Can anyone recommend some online resource(s) that will explain delegates in a way that presumes nothing? This is one of those moments where I suspect that VB actually handicaps me because it does some wiring for me behind the scenes. The ideal resource would just explain what delegates are, without reference to anything else like (events and eventhandlers), would show me how all everything is wired up, explain (as I just learned) that delegates are types and what makes them unique as a type (perhaps using a little ildasm magic)). That foundation would then expand to explain how delegates are related to events and eventhandlers which would need a pretty good explanation in there own right. Finally this resource could tie it all together using real examples and explain what wiring DOES happen automatically by the compiler, how to use them, etc. And, oh yeah, when you should and should not use delegates, in other words, downsides and alternatives to using delegates. What say ye? Can any of you point me to resource(s) that can help me begin my journey to mastery? EDIT One last thing. The ideal resource will explain how you can and cannot use delegates in an interface declaration. That is something that really tripped me up. Thanks for your help. Seth

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  • PulpCore OGG music playback - can't loop as soon as I animate the musicVolume property

    - by Peter Perhác
    I have been experimenting with PulpCore for about a week or so and I am enjoying it very much but today I ran into a problem that I can't quite figure out. Sound bgMusic = Sound.load("music/music.ogg"); Playback musicPlayback; ... musicVolume = new Fixed(0.75); musicPlayback = bgMusic.loop(musicVolume); //TODO figure out why it's NOT looping when volume is animated // musicVolume.animate(0, musicVolume.get(), FADE_IN_TIME); This code, for as long as the last line is commented out, plays the music.ogg again and again in an endless loop (which I can stop by calling stop on the Playback object returned from loop(). However, I would like the music to fade in smoothly, so following the advice of the PulpCore API docs, I added the last line which will create the fade-in but the music will only play once and then stop. I wonder why is that? Here is a bit of the documentation: Playback pulpcore.sound.Sound.loop(Fixed level) Loops this sound clip with the specified volume level (0.0 to 1.0). The level may have a property animation attached. Parameters: level Returns: a Playback object for this unique sound playback (one Sound can have many simultaneous Playback objects) or null if the sound could not be played. So what could be the problem? I repeat, with the last line, the sound fades in but doesn't loop, without it it loops but starts with the specified 0.75 volume level.

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  • How to estimate tomcat server requirements?

    - by Daniil
    We have a brand new webapp written that runs on Tomcat. So far, only one client is using it through the day. They run about 180 unique logins a day. Not really a lot IMO. Now, we managed to sell it to a brand new client who likes and wants to roll it out to 50,000 clients. How many of them will login at the same time - no idea. But I need to do the whole thing - allocate, create, config and maintain. OK - last is simple(errrr). The application runs off of Tomcat 5.5 on Gentoo (I'm thinking to upgrade to Tomcat 6) with MSSQL & mySQL behind. I do realize that a more enterprise ready application would be a better fit, but that's not an option at the moment. Since I've never done this before, I'm a bit lost. Can someone advice on how to go about estimating the equipment requirements for this client? Tomcat does have clustering, so that I can do. MS SQL - I'm sure they have something too. I'm thinking to stick it behind LVS (which we do use at the moment for something else too). Any help from people who deal with these details is greatly appreciated!

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  • Rails does not display error messages on a form in a custom method

    - by slythic
    Hi all, I've created a custom method called checkout in my app. I create an order (which is done my adding products to my "cart"), assign it to my client, and then I head to my checkout screen where I confirm the items and enter their customer order number and complete the order (submit). Everything works great except that it doesn't display error messages. I'm able to display a flash error notice (seen in complete_order method) when things go wrong but it doesn't specify the details like a normal form would. The error messages should appear if the customer order number is not unique for that client. Below is the custom method (checkout) related code. Order Model: validates_uniqueness_of :customer_order_number, :scope => :client_id Orders_controller: def checkout @order = current_order end def complete_order @order = current_order respond_to do |format| if @order.update_attributes(params[:order]) @order.complete #sets submitted datetime and state to 'complete' flash[:notice] = 'Thank you! Your order is being processed.' format.html { redirect_to( products_path ) } format.xml { head :ok } else flash[:error] = 'Please review your items' #added to confirm an error is present format.html { redirect_to( checkout_path ) } format.xml { render :xml => @order.errors, :status => :unprocessable_entity } end end end And the form in the checkout view: <% form_for @order, :url => { :controller => "orders", :action => "complete_order" } do |f| %> <%= f.error_messages %> <%= f.text_field :customer_order_number, :label => "Purchase Order Number" %> <p> <%= f.submit 'Complete Order', :confirm => 'Are you sure?' %> <small> or <%= link_to 'cancel', current_cart_path %></small> </p> <% end %> Any idea how I can display the specific error messages? Thank you in advance! -Tony

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  • MySQL DDL error creating tables

    - by Alexandstein
    I am attempting to create tables for a MySQL database, but I am having some syntactical issues. It would seem that syntax checking is behaving differently between tables for some reason. While I've gotten all the other tables to go through, the table, 'stock' doesn't seem to be working, despite seeming to use the same syntax patterns. CREATE TABLE users ( user_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, username VARCHAR(30) NOT NULL, password CHAR(41) NOT NULL, date_joined DATETIME NOT NULL, funds DOUBLE UNSIGNED NOT NULL, PRIMARY KEY(user_id), UNIQUE KEY(username) ); CREATE TABLE owned_stocks ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, user_id SMALLINT UNSIGNED NOT NULL, paid_price DOUBLE UNSIGNED NOT NULL, quantity MEDIUMINT UNSIGNED NOT NULL, purchase_date DATETIME NOT NULL, PRIMARY KEY(id) ); CREATE TABLE tracking_stocks ( ticker VARCHAR(5) NOT NULL, user_id SMALLINT UNSIGNED NOT NULL, PRIMARY KEY(ticker) ); CREATE TABLE stocks ( ticker VARCHAR(5) NOT NULL, last DOUBLE UNSIGNED NOT NULL, high DOUBLE UNSIGNED NOT NULL, low DOUBLE UNSIGNED NOT NULL, company_name VARCHAR(30) NOT NULL, last_updated INT UNSIGNED NOT NULL, change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, PRIMARY KEY(ticker) ); Am I just missing a really obvious syntactical issue? ERROR: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, last DOUBLE' at line 4

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  • Data synchronization using XMPP

    - by Jason
    Hi: I'm looking for some insight/advice on synchronizing data over XMPP. I've never developed anything for XMPP before so excuse me if some of my questions seem ridiculous. Basically, what I have is a decentralized social network. Each person has it's own Web site (or server) with a unique URI (one domain could host many servers). Each of these servers can have many clients. E.g., a desktop application, mobile application, etc. What I would like to accomplish is near real-time synchronization/communication between client and server, e.g., I update something on my desktop application, I see it change on my Web site. My server and client code is Python. So, I would like to make use of SleekXMPP if possible (it's license seems to have changed to MIT). I was thinking, and here is where I need advice, that each server would register an account at a dedicated XMPP server, e.g., [email protected]. and then I could use different resources for clients [email protected]/client1, [email protected]/client2, etc. If anyone can register any username, then maybe I also need some intermediate service (since it's decentralized, i'm not sure how to control registrations). Another option, I guess, is that each server runs it's own xmpp server. Assuming, that was all worked out, if I want to broadcast messages to all my resources (except the sending one), how do I do that? Do I have to subscribe to myself? This also seems like a good candidate for publish-subscribe, let me know if you think that could work and what the design/flow of that process would be. thanks :)

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  • how do simple SQLAlchemy relationships work?

    - by Carson Myers
    I'm no database expert -- I just know the basics, really. I've picked up SQLAlchemy for a small project, and I'm using the declarative base configuration rather than the "normal" way. This way seems a lot simpler. However, while setting up my database schema, I realized I don't understand some database relationship concepts. If I had a many-to-one relationship before, for example, articles by authors (where each article could be written by only a single author), I would put an author_id field in my articles column. But SQLAlchemy has this ForeignKey object, and a relationship function with a backref kwarg, and I have no idea what any of it MEANS. I'm scared to find out what a many-to-many relationship with an intermediate table looks like (when I need additional data about each relationship). Can someone demystify this for me? Right now I'm setting up to allow openID auth for my application. So I've got this: from __init__ import Base from sqlalchemy.schema import Column from sqlalchemy.types import Integer, String class Users(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) username = Column(String, unique=True) email = Column(String) password = Column(String) salt = Column(String) class OpenID(Base): __tablename__ = 'openid' url = Column(String, primary_key=True) user_id = #? I think the ? should be replaced by Column(Integer, ForeignKey('users.id')), but I'm not sure -- and do I need to put openids = relationship("OpenID", backref="users") in the Users class? Why? What does it do? What is a backref?

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  • XSD any element

    - by ofer shwartz
    HI! I'm trying to create a list that some of the elements are defined and some are not, without priority to order. I tried it this way, with an any element: <?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:complexType name="object" mixed="true"> <xs:choice> <xs:element name="value" minOccurs="1" maxOccurs="1"> <xs:simpleType> <xs:restriction base="xs:integer"> <xs:enumeration value="1"/> </xs:restriction> </xs:simpleType> </xs:element> <xs:any namespace="##any" processContents="skip"/> </xs:choice> </xs:complexType> <xs:element name="object" type="object"/> </xs:schema> And it tells me this error: :0:0: error: complex type 'object' violates the unique particle attribution rule in its components 'value' and '##any' Can someone help me out solve the problem? Ofer

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  • ASP.NET DropDownList posting ""

    - by Daniel
    I am using ASP.NET forms version 3.5 in VB I have a dropdownlist that is filled with data from a DB with a list of countries The code for the dropdown list is <label class="ob_label"> <asp:DropDownList ID="lstCountry" runat="server" CssClass="ob_forminput"> </asp:DropDownList> Country*</label> And the code that the list is Dim selectSQL As String = "exec dbo.*******************" ' Define the ADO.NET objects. Dim con As New SqlConnection(connectionString) Dim cmd As New SqlCommand(selectSQL, con) Dim reader As SqlDataReader ' Try to open database and read information. Try con.Open() reader = cmd.ExecuteReader() ' For each item, add the author name to the displayed ' list box text, and store the unique ID in the Value property. Do While reader.Read() Dim newItem As New ListItem() newItem.Text = reader("AllSites_Countries_Name") newItem.Value = reader("AllSites_Countries_Id") CType(LoginViewCart.FindControl("lstCountry"), DropDownList).Items.Add(newItem) Loop reader.Close() CType(LoginViewCart.FindControl("lstCountry"), DropDownList).SelectedValue = 182 Catch Err As Exception Response.Redirect("~/error-on-page/") MailSender.SendMailMessage("*********************", "", "", OrangeBoxSiteId.SiteName & " Error Catcher", "<p>Error in sub FillCountry</p><p>Error on page:" & HttpContext.Current.Request.Url.AbsoluteUri & "</p><p>Error details: " & Err.Message & "</p>") Response.Redirect("~/error-on-page/") Finally con.Close() End Try When the form is submitted an error occurs which says that the string "" cannot be converted to the datatype integer. For some reason the dropdownlist is posting "" rather than the value for the selected country.

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  • Django db encoding

    - by realshadow
    Hey, I have a little problem with encoding. The data in db is ok, when I select the data in php its ok. Problem comes when I get the data and try to print it in the template, I get - Å port instead of Šport, etc. Everything is set to utf-8 - in settings.py, meta tags in template, db table and I even have unicode method specified for the model, but nothing seems to work. I am getting pretty hopeless here... Here is some code: class Category_info(models.Model): objtree_label_id = models.AutoField(primary_key = True) node_id = models.IntegerField(unique = True) language_id = models.IntegerField() label = models.CharField(max_length = 255) type_id = models.IntegerField() class Meta: db_table = 'objtree_labels' def __unicode__(self): return self.label I have even tried with return u"%s" % self.label. Here is the view: def categories_list(request): categories_list = Category.objects.filter(parent_id = 1, status = 1) paginator = Paginator(categories_list, 10) try: page = int(request.GET.get('page', 1)) except ValueError: page = 1 try: categories = paginator.page(page) except (EmptyPage, InvalidPage): categories = paginator.page(paginator.num_pages) return render_to_response('categories_list.html', {'categories': categories}) Maybe I am just blind and/or stupid, but it just doesnt work. So any help is appreciated, thanks in advance. Regards

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  • Backreferences syntax in replacement strings (why dollar sign?)

    - by polygenelubricants
    In Java, and it seems in a few other languages, backreferences in the pattern is preceded by a slash (e.g. \1, \2, \3, etc), but in a replacement string it's preceded by a dollar sign (e.g. $1, $2, $3, and also $0). Here's a snippet to illustrate: System.out.println( "left-right".replaceAll("(.*)-(.*)", "\\2-\\1") // WRONG!!! ); // prints "2-1" System.out.println( "left-right".replaceAll("(.*)-(.*)", "$2-$1") // CORRECT! ); // prints "right-left" System.out.println( "You want million dollar?!?".replaceAll("(\\w*) dollar", "US\\$ $1") ); // prints "You want US$ million?!?" System.out.println( "You want million dollar?!?".replaceAll("(\\w*) dollar", "US$ \\1") ); // throws IllegalArgumentException: Illegal group reference Questions: Is the use of $ for backreferences in replacement strings unique to Java? If not, what language started it? What flavors use it and what don't? Why is this a good idea? Why not stick to the same pattern syntax? Wouldn't that lead to a more cohesive and an easier to learn language? Wouldn't the syntax be more streamlined if statements 1 and 4 in the above were the "correct" ones instead of 2 and 3?

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  • How to insert records in master/detail relationship

    - by croceldon
    I have two tables: OutputPackages (master) |PackageID| OutputItems (detail) |ItemID|PackageID| OutputItems has an index called 'idxPackage' set on the PackageID column. ItemID is set to auto increment. Here's the code I'm using to insert masters/details into these tables: //fill packages table for i := 1 to 10 do begin Package := TfPackage(dlgSummary.fcPackageForms.Forms[i]); if Package.PackageLoaded then begin with tblOutputPackages do begin Insert; FieldByName('PackageID').AsInteger := Package.ourNum; FieldByName('Description').AsString := Package.Title; FieldByName('Total').AsCurrency := Package.Total; Post; end; //fill items table for ii := 1 to 10 do begin Item := TfPackagedItemEdit(Package.fc.Forms[ii]); if Item.Activated then begin with tblOutputItems do begin Append; FieldByName('PackageID').AsInteger := Package.ourNum; FieldByName('Description').AsString := Item.Description; FieldByName('Comment').AsString := Item.Comment; FieldByName('Price').AsCurrency := Item.Price; Post; //this causes the primary key exception end; end; end; end; This works fine as long as I don't mess with the MasterSource/MasterFields properties in the IDE. But once I set it, and run this code I get an error that says I've got a duplicate primary key 'ItemID'. I'm not sure what's going on - this is my first foray into master/detail, so something may be setup wrong. I'm using ComponentAce's Absolute Database for this project. How can I get this to insert properly? Update Ok, I removed the primary key restraint in my db, and I see that for some reason, the autoincrement feature of the OutputItems table isn't working like I expected. Here's how the OutputItems table looks after running the above code: ItemID|PackageID| 1 |1 | 1 |1 | 2 |2 | 2 |2 | I still don't see why all the ItemID values aren't unique.... Any ideas?

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  • What is a faster way of merging the values of this Python structure into a single dictionary?

    - by jcoon
    I've refactored how the merged-dictionary (all_classes) below is created, but I'm wondering if it can be more efficient. I have a dictionary of dictionaries, like this: groups_and_classes = {'group_1': {'class_A': [1, 2, 3], 'class_B': [1, 3, 5, 7], 'class_c': [1, 2], # ...many more items like this }, 'group_2': {'class_A': [11, 12, 13], 'class_C': [5, 6, 7, 8, 9] }, # ...and many more items like this } A function creates a new object from groups_and_classes like this (the function to create this is called often): all_classes = {'class_A': [1, 2, 3, 11, 12, 13], 'class_B': [1, 3, 5, 7, 9], 'class_C': [1, 2, 5, 6, 7, 8, 9] } Right now, there is a loop that does this: all_classes = {} for group in groups_and_classes.values(): for c, vals in group.iteritems(): for v in vals: if all_classes.has_key(c): if v not in all_classes[c]: all_classes[c].append(v) else: all_classes[c] = [v] So far, I changed the code to use a set instead of a list since the order of the list doesn't matter and the values need to be unique: all_classes = {} for group in groups_and_classes.values(): for c, vals in group.iteritems(): try: all_classes[c].update(set(vals)) except KeyError: all_classes[c] = set(vals) This is a little nicer, and I didn't have to convert the sets to lists because of how all_classes is used in the code. Question: Is there a more efficient way of creating all_classes (aside from building it at the same time groups_and_classes is built, and changing everywhere this function is called)?

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  • User preferences using SQL and JavaScript

    - by Shyam
    Hi, I am using Server Side JavaScript - yes, I am actually using Server Side JavaScript. To complexify things even more, I use Oracle as a backend database (10g). With some crazy XSLT and mutant-like HTML generation, I can build really fancy web forms - yes, I am aware of Rails and other likewise frameworks and I choose the path of horror instead. I have no JQuery or other fancy framework at my disposal, just plain ol' JavaScript that should be supported by the underlying engine called Mozilla Rhino. Yes, it is insane and I love it. So, I have a bunch of tables at my disposal and some of them are filled with associative keys that link to values. As I am a people pleaser, I want to add some nifty user-preference driven solutions. My users have all an unique user_id and this user_id is available during the entire session. My initial idea is to have a user preference table, where I have "three" columns: user_id, feature and pref_string. Using a delimiter, such as : or - (haven't thought about a suitable one yet), I could like store a bunch of preferences as a list and store its elements inside an array using the .split-method (similar like the PHP-explode function). The feature column could be like the table name or some identifier for the "feature" i want to link preferences too. I hate hardcoding objects, especially as I want to be able to back these up and reuse this functionality application-wide. Of course I would love better ideas, just keep in mind I cannot just add a library that easily. These preferences could be like "joined" to the table, so I can query it and use its values. I hope it doesn't sounds too complex, because well.. its basically something really simple I need. Thanks!

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  • SQLAlchemy: select over multiple tables

    - by ahojnnes
    Hi, I wanted to optimize my database query: link_list = select( columns=[link_table.c.rating, link_table.c.url, link_table.c.donations_in], whereclause=and_( not_(link_table.c.id.in_( select( columns=[request_table.c.recipient], whereclause=request_table.c.donator==donator.id ).as_scalar() )), link_table.c.id!=donator.id, ), limit=20, ).execute().fetchall() and tried to merge those two selects in one query: link_list = select( columns=[link_table.c.rating, link_table.c.url, link_table.c.donations_in], whereclause=and_( link_table.c.active==True, link_table.c.id!=donator.id, request_table.c.donator==donator.id, link_table.c.id!=request_table.c.recipient, ), limit=20, order_by=[link_table.c.rating.desc()] ).execute().fetchall() the database-schema looks like: link_table = Table('links', metadata, Column('id', Integer, primary_key=True, autoincrement=True), Column('url', Unicode(250), index=True, unique=True), Column('registration_date', DateTime), Column('donations_in', Integer), Column('active', Boolean), ) request_table = Table('requests', metadata, Column('id', Integer, primary_key=True, autoincrement=True), Column('recipient', Integer, ForeignKey('links.id')), Column('donator', Integer, ForeignKey('links.id')), Column('date', DateTime), ) There are several links (donator) in request_table pointing to one link in the link_table. I want to have links from link_table, which are not yet "requested". But this does not work. Is it actually possible, what I'm trying to do? If so, how would you do that? Thank you very much in advance!

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  • use awk to identify multi-line record and filtering

    - by nanshi
    I need to process a big data file that contains multi-line records, example input: 1 Name Dan 1 Title Professor 1 Address aaa street 1 City xxx city 1 State yyy 1 Phone 123-456-7890 2 Name Luke 2 Title Professor 2 Address bbb street 2 City xxx city 3 Name Tom 3 Title Associate Professor 3 Like Golf 4 Name 4 Title Trainer 4 Likes Running Note that the first integer field is unique and really identifies a whole record. So in the above input I really have 4 records although I dont know how many lines of attributes each records may have. I need to: - identify valid record (must have "Name" and "Title" field) - output the available attributes for each valid record, say "Name", "Title", "Address" are needed fields. Example output: 1 Name Dan 1 Title Professor 1 Address aaa street 2 Name Luke 2 Title Professor 2 Address bbb street 3 Name Tom 3 Title Associate Professor So in the output file, record 4 is removed since it doen't have the "Name" field. Record 3 doesn't have Address field but still being print to the output since it is a valid record that has "Name" and "Title". Can I do this with awk? But how do i identify a whole record using the first "id" field on each line? Thanks a lot to the unix shell script expert for helping me out! :)

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  • Counting total sum of each value in one column w.r.t another in Perl

    - by sfactor
    I have tab delimited data with multiple columns. I have OS names in column 31 and data bytes in columns 6 and 7. What I want to do is count the total volume of each unique OS. So, I did something in Perl like this: #!/usr/bin/perl use warnings; my @hhfilelist = glob "*.txt"; my %count = (); for my $f (@hhfilelist) { open F, $f || die "Cannot open $f: $!"; while (<F>) { chomp; my @line = split /\t/; # counting volumes in col 6 and 7 for 31 $count{$line[30]} = $line[5] + $line[6]; } close (F); } my $w = 0; foreach $w (sort keys %count) { print "$w\t$count{$w}\n"; } So, the result would be something like Windows 100000 Linux 5000 Mac OSX 15000 Android 2000 But there seems to be some error in this code because the resulting values I get aren't as expected. What am I doing wrong?

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  • AVAudioPlayer not unloading cached memory after each new allocation

    - by Rob
    I am seeing in Instruments that when I play a sound via the standard "AddMusic" example method that Apple provides, it allocates 32kb of memory via the prepareToPlay call (which references the AudioToolBox framework's Cache_DataSource::ReadBytes function) each time a new player is allocated (i.e. each time a different sound is played). However, that cached data never gets released. This obviously poses a huge problem if it doesn't get released and you have a lot of sound files to play, since it tends to keep allocating memory and eventually crashes if you have enough unique sound files (which I unfortunately do). Have any of you run across this or what am I doing wrong in my code? I've had this issue for a while now and it's really bugging me since my code is verbatim of what Apple's is (I think). How I call the function: - (void)playOnce:(NSString *)aSound { // Gets the file system path to the sound to play. NSString *soundFilePath = [[NSBundle mainBundle] pathForResource:aSound ofType:@"caf"]; // Converts the sound's file path to an NSURL object NSURL *soundURL = [[NSURL alloc] initFileURLWithPath: soundFilePath]; self.soundFileURL = soundURL; [soundURL release]; AVAudioPlayer * newAudio=[[AVAudioPlayer alloc] initWithContentsOfURL: soundFileURL error:nil]; self.theAudio = newAudio; // automatically retain audio and dealloc old file if new m4a file is loaded [newAudio release]; // release the audio safely // this is where the prior cached data never gets released [theAudio prepareToPlay]; // set it up and play [theAudio setNumberOfLoops:0]; [theAudio setVolume: volumeLevel]; [theAudio setDelegate: self]; [theAudio play]; } and then theAudio gets released in the dealloc method of course.

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  • How do I make the following interaction with mySQL more efficient?

    - by Travis
    I've got an array that contains combinations of unique MySql IDs: For example: [ [1,10,11], [2,10], [3,10,12], [3,12,13,20], [4,12] ] In total there are a couple hundred different combinations of IDs. Some of these combinations are "valid" and some are not. For example, [1,10,11] may be a valid combination, whereas [3,10,12] may be invalid. Combinations are valid or invalid depending on how the data is arranged in the database. Currently I am using a SELECT statement to determine whether or not a specific combination of IDs is valid. It looks something like this: SELECT id1 FROM table WHERE id2 IN ($combination) GROUP BY id1 HAVING COUNT(distinct id2) = $number ...where $combination is one possible combination of IDs (eg 1,10,11) and $number is the number of IDs in that combination (in this case, 3). An invalid combination will return 0 rows. A valid combination will return 1 or more rows. However, to solve the entire set of possible combinations means looping a couple hundred SELECT statements, which I would rather not be doing. I am wondering: Are there any tricks for making this more efficient? Is it possible to submit the entire dataset to mySQL in one go, and have mySQL iterate through it? Any suggestions would be much appreciated. Thanks in advance!

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  • How to pass a Dictionary variable to another procedure

    - by salvationishere
    I am developing a C# VS2008/SQL Server website application. I've never used the Dictionary class before, but I am trying to replace my Hashtable with a Dictionary variable. Here is a portion of my aspx.cs code: ... Dictionary<string, string> openWith = new Dictionary<string, string>(); for (int col = 0; col < headers.Length; col++) { @temp = (col + 1); @tempS = @temp.ToString(); @tempT = "@col" + @temp.ToString(); ... openWith.Add(@tempT, headers[col]); } ... for (int r = 0; r < myInputFile.Rows.Count; r++) { resultLabel.Text = ADONET_methods.AppendDataCT(myInputFile, openWith); } But this is giving me a compiler error on this last line: Argument '2': cannot convert from 'System.Collections.Generic.Dictionary' to 'string' How do I pass the entire openWith variable to AppendDataCT? AppendDataCT is the method that calls my SQL stored proc. I want to pass in the whole row where each row has a unique set of values that I want to add to my database table. For example, if each row requires values for cells A, B, and C, then I want to pass these 3 values to AppendDataCT, where all of these values are strings. How do I do this with Dictionary?

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  • error in finding out the lexems and no of lines of a text file in C

    - by mekasperasky
    #include<stdio.h> #include<ctype.h> #include<string.h> int main() { int i=0,j,k,lines_count[2]={1,1},operand_count[2]={0},operator_count[2]={0},uoperator_count[2]={0},control_count[2]={0,0},cl[13]={0},variable_dec[2]={0,0},l,p[2]={0},ct,variable_used[2]={0,0},constant_count[2],s[2]={0},t[2]={0}; char a,b[100],c[100]; char d[100]={0}; j=30; FILE *fp1[2],*fp2; fp1[0]=fopen("program1.txt","r"); fp1[1]=fopen("program2.txt","r"); //the source file is opened in read only mode which will passed through the lexer fp2=fopen("ccv1ouput.txt","wb"); //now lets remove all the white spaces and store the rest of the words in a file if(fp1[0]==NULL) { perror("failed to open program1.txt"); //return EXIT_FAILURE; } if(fp1[1]==NULL) { perror("failed to open program2.txt"); //return EXIT_FAILURE; } i=0; k=0; ct=0; while(ct!=2) { while(!feof(fp1[ct])) { a=fgetc(fp1[ct]); if(a!=' '&&a!='\n') { if (!isalpha(a) && !isdigit(a)) { switch(a) { case '+':{ i=0; cl[0]=1; operator_count[ct]=operator_count[ct]+1;break;} case '-':{ cl[1]=1; operator_count[ct]=operator_count[ct]+1;i=0;break;} case '*':{ cl[2]=1; operator_count[ct]=operator_count[ct]+1;i=0;break;} case '/':{ cl[3]=1; operator_count[ct]=operator_count[ct]+1;i=0;break;} case '=':{a=fgetc(fp1[ct]); if (a=='='){cl[4]=1; operator_count[ct]=operator_count[ct]+1; operand_count[ct]=operand_count[ct]+1;} else { cl[5]=1; operator_count[ct]=operator_count[ct]+1; operand_count[ct]=operand_count[ct]+1; ungetc(1,fp1[ct]); } break;} case '%':{ cl[6]=1; operator_count[ct]=operator_count[ct]+1;i=0;break;} case '<':{ a=fgetc(fp1[ct]); if (a=='=') {cl[7]=1; operator_count[ct]=operator_count[ct]+1;} else { cl[8]=1; operator_count[ct]=operator_count[ct]+1; ungetc(1,fp1[ct]); } break; } case '>':{ ; a=fgetc(fp1[ct]); if (a=='='){cl[9]=1; operator_count[ct]=operator_count[ct]+1;} else { cl[10]=1; operator_count[ct]=operator_count[ct]+1; ungetc(1,fp1[ct]); } break;} case '&':{ cl[11]=1; a=fgetc(fp1[ct]); operator_count[ct]=operator_count[ct]+1; operand_count[ct]=operand_count[ct]+1; variable_used[ct]=variable_used[ct]-1; break; } case '|':{ cl[12]=1; a=fgetc(fp1[ct]); operator_count[ct]=operator_count[ct]+1; operand_count[ct]=operand_count[ct]+1; variable_used[ct]=variable_used[ct]-1; break; } case '#':{ while(a!='\n') { a=fgetc(fp1[ct]); } } } } else { d[i]=a; i=i+1; k=k+1; } } else { //printf("%s \n",d); if((strcmp(d,"if")==0)){ memset ( d, 0, 100 ); i=0; control_count[ct]=control_count[ct]+1; } else if(strcmp(d,"then")==0){ i=0;memset ( d, 0, 100 );control_count[ct]=control_count[ct]+1;} else if(strcmp(d,"else")==0){ i=0;memset ( d, 0, 100 );control_count[ct]=control_count[ct]+1;} else if(strcmp(d,"while")==0){ i=0;memset ( d, 0, 100 );control_count[ct]=control_count[ct]+1;} else if(strcmp(d,"int")==0){ while(a != '\n') { a=fgetc(fp1[ct]); if (isalpha(a) ) variable_dec[ct]=variable_dec[ct]+1; } memset ( d, 0, 100 ); lines_count[ct]=lines_count[ct]+1; } else if(strcmp(d,"char")==0){while(a != '\n') { a=fgetc(fp1[ct]); if (isalpha(a) ) variable_dec[ct]=variable_dec[ct]+1; } memset ( d, 0, 100 ); lines_count[ct]=lines_count[ct]+1; } else if(strcmp(d,"float")==0){while(a != '\n') { a=fgetc(fp1[ct]); if (isalpha(a) ) variable_dec[ct]=variable_dec[ct]+1; } memset ( d, 0, 100 ); lines_count[ct]=lines_count[ct]+1; } else if(strcmp(d,"printf")==0){while(a!='\n') a=fgetc(fp1[ct]); memset(d,0,100); } else if(strcmp(d,"scanf")==0){while(a!='\n') a=fgetc(fp1[ct]); memset(d,0,100);} else if (isdigit(d[i-1])) { memset ( d, 0, 100 ); i=0; constant_count[ct]=constant_count[ct]+1; operand_count[ct]=operand_count[ct]+1; } else if (isalpha(d[i-1]) && strcmp(d,"int")!=0 && strcmp(d,"char")!=0 && strcmp(d,"float")!=0 && (strcmp(d,"if")!=0) && strcmp(d,"then")!=0 && strcmp(d,"else")!=0 && strcmp(d,"while")!=0 && strcmp(d,"printf")!=0 && strcmp(d,"scanf")!=0) { memset ( d, 0, 100 ); i=0; operand_count[ct]=operand_count[ct]+1; } else if(a=='\n') { lines_count[ct]=lines_count[ct]+1; memset ( d, 0, 100 ); } } } fclose(fp1[ct]); operand_count[ct]=operand_count[ct]-5; variable_used[0]=operand_count[0]-constant_count[0]; variable_used[1]=operand_count[1]-constant_count[1]; for(j=0;j<12;j++) uoperator_count[ct]=uoperator_count[ct]+cl[j]; fprintf(fp2,"\n statistics of program %d",ct+1); fprintf(fp2,"\n the no of lines ---> %d",lines_count[ct]); fprintf(fp2,"\n the no of operands --->%d",operand_count[ct]); fprintf(fp2,"\n the no of operator --->%d",operator_count[ct]); fprintf(fp2,"\n the no of control statments --->%d",control_count[ct]); fprintf(fp2,"\n the no of unique operators --->%d",uoperator_count[ct]); fprintf(fp2,"\n the no of variables declared--->%d",variable_dec[ct]); fprintf(fp2,"\n the no of variables used--->%d",variable_used[ct]); fprintf(fp2,"\n ---------------------------------"); fprintf(fp2,"\n \t \t \t"); ct=ct+1; } t[0]=lines_count[0]+control_count[0]+uoperator_count[0]; t[1]=lines_count[1]+control_count[1]+uoperator_count[1]; s[0]=operator_count[0]+operand_count[0]+variable_dec[0]+variable_used[0]; s[1]=operator_count[1]+operand_count[1]+variable_dec[1]+variable_used[1]; fprintf(fp2,"\n the time complexity of program 1 is %d",t[0]); fprintf(fp2,"\n the time complexity of program 2 is %d",t[1]); fprintf(fp2,"\n the space complexity of program 1 is %d",s[0]); fprintf(fp2,"\n the space complexity of program 2 is %d",s[1]); if((t[0]>t[1]) && (s[0] >s[1])) fprintf(fp2,"\n the efficiency of program 2 is greater than program 1"); else if(t[0]<t[1] && s[0] < s[1]) fprintf(fp2,"\n the efficiency of program 1 is greater than program 2 " ); else if (t[0]+s[0] > t[1]+s[1]) fprintf(fp2,"\n the efficiency of program 1 is greater than program 2"); else if (t[0]+s[0] < t[1]+s[1]) fprintf(fp2,"\n the efficiency of program 2 is greater than program 1"); else if (t[0]+s[0] == t[1]+s[1]) fprintf(fp2,"\n the efficiency of program 1 is equal to that of program 2"); fclose(fp2); return 0; } this code basically compares two c codes and finds out the no. of variables declared , used , no. of control statements , no. of lines and no. of unique operators , and operands , so as to find out the time complexity and space complexity of of the two programs given in the text file program1.txt and program2.txt ... Lets say program1.txt is this #include<stdio.h> #include<math.h> int main () { FILE *fp; fp=fopen("output.txt","w"); long double t,y=0,x=0,e=5,f=1,w=1; for (t=0;t<10;t=t+0.01) { //if (isnan(y) || isinf(y)) //break; fprintf(fp,"%ld\t%ld\n",y,x); y = y + ((e*(1 - (x*x))*y) - x + f*cos(w*0.1))*0.1; x = x + y*0.1; } fclose(fp); return (0); } i havent indented it as its just a text file . But my output is totally faulty . Its not able to find the any of the ouput that i need . Where is the bug in this ? I am not able to figure out as the algorithm looks fine .

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  • Simple encryption - Sum of Hashes in C

    - by Dogbert
    I am attempting to demonstrate a simple proof of concept with respect to a vulnerability in a piece of code in a game written in C. Let's say that we want to validate a character login. The login is handled by the user choosing n items, (let's just assume n=5 for now) from a graphical menu. The items are all medieval themed: eg: _______________________________ | | | | | Bow | Sword | Staff | |-----------|-----------|-------| | Shield | Potion | Gold | |___________|___________|_______| The user must click on each item, then choose a number for each item. The validation algorithm then does the following: Determines which items were selected Drops each string to lowercase (ie: Bow becomes bow, etc) Calculates a simple string hash for each string (ie: `bow = b=2, o=15, w=23, sum = (2+15+23=40) Multiplies the hash by the value the user selected for the corresponding item; This new value is called the key Sums together the keys for each of the selected items; this is the final validation hash IMPORTANT: The validator will accept this hash, along with non-zero multiples of it (ie: if the final hash equals 1111, then 2222, 3333, 8888, etc are also valid). So, for example, let's say I select: Bow (1) Sword (2) Staff (10) Shield (1) Potion (6) The algorithm drops each of these strings to lowercase, calculates their string hashes, multiplies that hash by the number selected for each string, then sums these keys together. eg: Final_Validation_Hash = 1*HASH(Bow) + 2*HASH(Sword) + 10*HASH(Staff) + 1*HASH(Shield) + 6*HASH(Potion) By application of Euler's Method, I plan to demonstrate that these hashes are not unique, and want to devise a simple application to prove it. in my case, for 5 items, I would essentially be trying to calculate: (B)(y) = (A_1)(x_1) + (A_2)(x_2) + (A_3)(x_3) + (A_4)(x_4) + (A_5)(x_5) Where: B is arbitrary A_j are the selected coefficients/values for each string/category x_j are the hash values for each string/category y is the final validation hash (eg: 1111 above) B,y,A_j,x_j are all discrete-valued, positive, and non-zero (ie: natural numbers) Can someone either assist me in solving this problem or point me to a similar example (ie: code, worked out equations, etc)? I just need to solve the final step (ie: (B)(Y) = ...). Thank you all in advance.

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  • OO vs Simplicity when it comes to user interaction

    - by Oetzi
    Firstly, sorry if this question is rather vague but it's something I'd really like an answer to. As a project over summer while I have some downtime from Uni I am going to build a monopoly game. This question is more about the general idea of the problem however, rather than the specific task I'm trying to carry out. I decided to build this with a bottom up approach, creating just movement around a forty space board and then moving on to interaction with spaces. I realised that I was quite unsure of the best way of proceeding with this and I am torn between two design ideas: Giving every space its own object, all sub-classes of a Space object so the interaction can be defined by the space object itself. I could do this by implementing different land() methods for each type of space. Only giving the Properties and Utilities (as each property has unique features) objects and creating methods for dealing with the buying/renting etc in the main class of the program (or Board as I'm calling it). Spaces like go and super tax could be implemented by a small set of conditionals checking to see if player is on a special space. Option 1 is obviously the OO (and I feel the correct) way of doing things but I'd like to only have to handle user interaction from the programs main class. In other words, I don't want the space objects to be interacting with the player. Why? Errr. A lot of the coding I've done thus far has had this simplicity but I'm not sure if this is a pipe dream or not for larger projects. Should I really be handling user interaction in an entirely separate class? As you can see I am quite confused about this situation. Is there some way round this? And, does anyone have any advice on practical OO design that could help in general?

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  • Best way to get a single value from a DataTable?

    - by PiersMyers
    I have a number of static classes that contain tables like this: using System; using System.Data; using System.Globalization; public static class TableFoo { private static readonly DataTable ItemTable; static TableFoo() { ItemTable = new DataTable("TableFoo") { Locale = CultureInfo.InvariantCulture }; ItemTable.Columns.Add("Id", typeof(int)); ItemTable.Columns["Id"].Unique = true; ItemTable.Columns.Add("Description", typeof(string)); ItemTable.Columns.Add("Data1", typeof(int)); ItemTable.Columns.Add("Data2", typeof(double)); ItemTable.Rows.Add(0, "Item 1", 1, 1.0); ItemTable.Rows.Add(1, "Item 2", 1, 1.0); ItemTable.Rows.Add(2, "Item 3", 2, 0.75); ItemTable.Rows.Add(3, "Item 4", 4, 0.25); ItemTable.Rows.Add(4, "Item 5", 1, 1.0); } public static DataTable GetItemTable() { return ItemTable; } public static int Data1(int id) { DataRow[] dr = ItemTable.Select("Id = " + id); if (dr.Length == 0) { throw new ArgumentOutOfRangeException("id", "Out of range."); } return (int)dr[0]["Data1"]; } public static double Data2(int id) { DataRow[] dr = ItemTable.Select("Id = " + id); if (dr.Length == 0) { throw new ArgumentOutOfRangeException("id", "Out of range."); } return (double)dr[0]["Data2"]; } } Is there a better way of writing the Data1 or Data2 methods that return a single value from a single row that matches the given id?

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  • Generating easy-to-remember random identifiers

    - by Carl Seleborg
    Hi all, As all developers do, we constantly deal with some kind of identifiers as part of our daily work. Most of the time, it's about bugs or support tickets. Our software, upon detecting a bug, creates a package that has a name formatted from a timestamp and a version number, which is a cheap way of creating reasonably unique identifiers to avoid mixing packages up. Example: "Bug Report 20101214 174856 6.4b2". My brain just isn't that good at remembering numbers. What I would love to have is a simple way of generating alpha-numeric identifiers that are easy to remember. Examples would be "azil3", "ulmops", "fel2way", etc. I just made these up, but they are much easier to recognize when you see many of them at once. I know of algorithms that perform trigram analysis on text (say you feed them a whole book in German) and that can generate strings that look and feel like German words. This requires lots of data, though, and makes it slightly less suitable for embedding in an application just for this purpose. Do you know of anything else? Thanks! Carl

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