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  • Arrays not counting correctly

    - by Nick Gibson
    I know I was just asking a question earlier facepalm This is in Java coding by the way. Well after everyones VERY VERY helpful advice (thank you guys alot) I managed to get over half of the program running how I wanted. Everything is pointing in the arrays where I want them to go. Now I just need to access the arrays so that It prints the correct information randomly. This is the current code that im using: http://pastebin.org/301483 The specific code giving me problems is this: long aa; int abc; for (int i = 0; i < x; i++) { aa = Math.round(Math.random()*10); String str = Long.toString(aa); abc = Integer.parseInt(str); String[] userAnswer = new String[x]; if(abc > x) { JOptionPane.showMessageDialog(null,"Number is too high. \nNumber Generator will reset."); break; } userAnswer[i] = JOptionPane.showInputDialog(null,"Question "+quesNum+"\n"+questions[abc]+"\n\nA: "+a[abc]+"\nB: "+b[abc]+"\nC: "+c[abc]+"\nD: "+d[abc]); answer = userAnswer[i].compareTo(answers[i]); if(answer == 0) { JOptionPane.showMessageDialog(null,"Correct. \nThe Correct Answer is "+answers[abc]+""+i); } else { JOptionPane.showMessageDialog(null,"Wrong. \n The Correct Answer is "+answers[abc]+""+i); }//else

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  • Using TXMLDocument to serialize form settings to XML and database.

    - by LukLed
    I have an interface: type IXMLSerializable = interface function SaveToXML : DOMString; function SaveToXMLDocument : IXMLDocument; procedure LoadFromXML(AXML : DOMString); end; It is used to serialize some settings of forms or frames to xml. Simple implementation: SaveToXMLDocument: function TSomething.SaveToXMLDocument: IXMLDocument; begin Result := TXMLDocument.Create(nil); with Result do begin Active := True; with AddChild(Self.Name) do begin AddChild(edSomeTextBox.Name).Attributes['Text'] := edSomeTextBox.Text; end; end; Result := XMLDoc; end; LoadFromXML: procedure TSomething.LoadFromXML(AXML: DOMString); var XMLDoc : IXMLDocument; I : Integer; begin XMLDoc := TXMLDocument.Create(nil); with XMLDoc do begin LoadFromXML(AXML); Active := True; with ChildNodes[0] do begin for I := 0 to ChildNodes.Count-1 do begin If ChildNodes[I].NodeName = 'edSomeTextBox' then edSomeTextBox.Text := ChildNodes[I].Attributes['Text']; end; end; end; end; SaveToXML: function TSomething.SaveToXML: DOMString; begin SaveToXMLDocument.SaveToXML(Result); end; DOMString result of SaveToXML is saved to database to blob field. I had some encoding issues with other implementations and this one works fine (right now). Do you see any dangers in this code? Can I have issues with different settings on various machines and systems?

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  • Algorithm to determine indices i..j of array A containing all the elements of another array B

    - by Skylark
    I came across this question on an interview questions thread. Here is the question: Given two integer arrays A [1..n] and B[1..m], find the smallest window in A that contains all elements of B. In other words, find a pair < i , j such that A[i..j] contains B[1..m]. If A doesn't contain all the elements of B, then i,j can be returned as -1. The integers in A need not be in the same order as they are in B. If there are more than one smallest window (different, but have the same size), then its enough to return one of them. Example: A[1,2,5,11,2,6,8,24,101,17,8] and B[5,2,11,8,17]. The algorithm should return i = 2 (index of 5 in A) and j = 9 (index of 17 in A). Now I can think of two variations. Let's suppose that B has duplicates. This variation doesn't consider the number of times each element occurs in B. It just checks for all the unique elements that occur in B and finds the smallest corresponding window in A that satisfies the above problem. For example, if A[1,2,4,5,7] and B[2,2,5], this variation doesn't bother about there being two 2's in B and just checks A for the unique integers in B namely 2 and 5 and hence returns i=1, j=3. This variation accounts for duplicates in B. If there are two 2's in B, then it expects to see at least two 2's in A as well. If not, it returns -1,-1. When you answer, please do let me know which variation you are answering. Pseudocode should do. Please mention space and time complexity if it is tricky to calculate it. Mention if your solution assumes array indices to start at 1 or 0 too. Thanks in advance.

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  • How to take a NSString such as, "0+1+2", get the sum of those and create new string. Obj-C

    - by Ace Legend
    Alright. My app has a text field and next to it are two buttons (Plus button and Equals button). When you press the "Plus" button, it takes the text inside of the textField and adds a "+" to it. Code below: - (IBAction)plusButtonPressed:(id)sender { NSString *plusString = @"+"; NSString *inputString = carbsField.text; NSString *outputString = [NSString stringWithFormat:@"%@%@",inputString,plusString]; NSLog(@"%@",outputString); [carbsField setText:outputString]; } I will eventually make that more intelligent so that I can't put two pluses or whatever. Anyway, then I want the equal button to take whatever is in the textField, which should look something like: "23+54+2.2" and get the sum of those values. I believe I know how to take an Integer and make it a String, but I want to verify it: int *value = 56; NSString *string = @"%d",value; Well, if anyone can show me how to do this, I would be very appreciative. Thanks. EDIT At the moment, I have not tried anything. This is because I do not know where to start. I have an idea of what to do, but I do not know how to execute it. I believe I need to get all characters before a "+" convert them into int and then get the sum of some array of those values.

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  • Speed/expensive of SQLite query vs. List.contains() for "in-set" icon on list rows

    - by kpdvx
    An application I'm developing requires that the app main a local list of things, let's say books, in a local "library." Users can access their local library of books and search for books using a remote web service. The app will be aware of other users of the app through this web service, and users can browse other users' lists of books in their library. Each book is identified by a unique bookId (represented as an int). When viewing books returned through a search result or when viewing another user's book library, the individual list row cells need to visually represent if the book is in the user's local library or not. A user can have at most 5,000 books in the library, stored in SQLite on the device (and synchronized with the remote web service). My question is, to determine if the book shown in the list row is in the user's library, would it be better to directly ask SQLite (via SELECT COUNT(*)...) or to maintain, in-memory, a List or int[] array of some sort containing the unique bookIds. So, on each row display do I query SQLite or check if the List or int[] array contains the unique bookId? Because the user can have at most 5,000 books, each bookId occupies 4 bytes so at most this would use ~ 20kB. In thinking about this, and in typing this out, it seems obvious to me that it would be far better for performance if I maintained a list or int[] array of in-library bookIds vs. querying SQLite (the only caveat to maintaining an int[] array is that if books are added or removed I'll need to grow or shrink the array by hand, so with this option I'll most likely use an ArrayList or Vector, though I'm not sure of the additional memory overhead of using Integer objects as opposed to primitives). Opinions, thoughts, suggestions?

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  • Adding a column to a model at runtime (without additional tables) in rails

    - by Marek
    I'm trying to give admins of my web application the ability to add some new fields to a model. The model is called Artwork and i would like to add, for instante, a test_column column at runtime. I'm just teting, so i added a simple link to do it, it will be of course parametric. I managed to do it through migrations: def test_migration_create Artwork.add_column :test_column, :integer flash[:notice] = "Added Column test_column to artworks" redirect_to :action => 'index' end def test_migration_delete Artwork.remove_column :test_column flash[:notice] = "Removed column test_column from artworks" redirect_to :action => 'index' end It works, the column gets added/ removed to/from the databse without issues. I'm using active_scaffold at the moment, so i get the test_column field in the form without adding anything. When i submit a create or an update, however, the test_column does not get updated and stay empty. Inspecting the parameters, i can see: Parameters: {"commit"=>"Update", "authenticity_token"=>"37Bo5pT2jeoXtyY1HgkEdIhglhz8iQL0i3XAx7vu9H4=", "id"=>"62", "record"=>{"number"=>"test_artwork", "author"=>"", "title"=>"Opera di Test", "test_column"=>"TEEST", "year"=>"", "description"=>""}} the test_column parameter is passed correctly. So why active record keeps ignoring it? I tried to restart the server too without success. I'm using ruby 1.8.7, rails 2.3.5, and mongrel with an sqlite3 database. Thanks

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  • ASP ListView - Eval() as formatted number, Bind() as unformatted?

    - by chucknelson
    I have an ASP ListView, and have a very simple requirement to display numbers as formatted w/ a comma (12,123), while they need to bind to the database without formatting (12123). I am using a standard setup - ListView with a datasource attached, using Bind(). I converted from some older code, so I'm not using ASP.NET controls, just form inputs...but I don't think it matters for this: <asp:SqlDataSource ID="MySqlDataSource" runat="server" ConnectionString='<%$ ConnectionStrings:ConnectionString1 %>' SelectCommand="SELECT NUMSTR FROM MY_TABLE WHERE ID = @ID" UpdateCommand= "UPDATE MY_TABLE SET NUMSTR = @NUMSTR WHERE ID = @ID"> </asp:SqlDataSource> <asp:ListView ID="MyListView" runat="server" DataSourceID="MySqlDataSource"> <LayoutTemplate> <div id="itemplaceholder" runat="server"></div> </LayoutTemplate> <ItemTemplate> <input type="text" name="NUMSTR" ID="NUMSTR" runat="server" value='<%#Bind("NUMSTR")%>' /> <asp:Button ID="UpdateButton" runat="server" Text="Update" Commandname="Update" /> </ItemTemplate> </asp:ListView> In the example above, NUMSTR is a number, but stored as a string in a SqlServer 2008 database. I'm also using the ItemTemplate as read and edit templates, to save on duplicate HTML. In the example, I only get the unformatted number. If I convert the field to an integer (via the SELECT) and use a format string like Bind("NUMSTR", "{0:###,###}"), it writes the formatted number to the database, and then fails when it tries to read it again (can't convert with the comma in there). Is there any elegant/simple solution to this? It's so easy to get the two-way binding going, and I would think there has to be a way to easily format things as well... Oh, and I'm trying to avoid the standard ItemTemplate and EditItemTemplate approach, just for sheer amount of markup required for that. Thanks!

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  • datagridviewcomboboxcolumn with datasource issue?

    - by Sarrrva
    i have some propblem in datagridviewcombobocolumn with custom datasource property in vb.net. when i add datasource it does not populate in datagridview combobox column it giving nothing.. any one please help me out from this problem... code comboboxcell: Public Overrides Sub InitializeEditingControl(ByVal rowIndex As Integer, ByVal initialFormattedValue As Object, ByVal dataGridViewCellStyle As DataGridViewCellStyle) ' Set the value of the editing control to the current cell value. MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle) Dim ctl As ComboEditingControl = CType(DataGridView.EditingControl, ComboEditingControl) ctl.DropDownStyle = ComboBoxStyle.DropDown ctl.AutoCompleteSource = AutoCompleteSource.ListItems ctl.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Suggest If (Me.DataGridView.Rows(rowIndex).Cells(0).Value <> Nothing) Then Dim GetValueFromRowToUseForBuildingCombo As String = Me.DataGridView.Rows(rowIndex).Cells(0).Value.ToString() ctl.Items.Clear() Dim dt As New DataTable() Try dt = TryCast(DirectCast(Me.DataGridView.Columns(ColumnIndex), ComboColumn).DataSource, DataTable) Catch ex As Exception MsgBox("error") End Try If (dt Is Nothing) Then ctl.Items.Add("") Else Dim thing As DataRow For Each thing In dt.Rows ctl.Items.Add(thing(0).ToString) Next End If If Me.Value Is Nothing Then ctl.SelectedIndex = -1 Else ctl.SelectedItem = Me.Value End If ctl.EditingControlDataGridView = Me.DataGridView End If End Sub from code: Dim widgets As New WidgetDataHandler Dim obj = widgets.GetAllWigetTypes() Dim dt As New DataTable Dim ListofmyObjects As New List(Of widget_types)(obj) Dim objList As New cObjectToTable(Of widget_types)(ListofmyObjects) dt = objList.GetTable() Dim obj1 For Each obj1 In obj blPersons.Add(obj1) Next Dim col1 As New DataGridViewTextBoxColumn col1.DisplayIndex = 0 col1.DataPropertyName = "Id" col1.HeaderText = "Id" dgvi00.Columns.Add(col1) Dim col2 As New ComboColumn col2.DisplayIndex = 1 col2.SortMode = DataGridViewColumnSortMode.Automatic col2.HeaderText = "Name" col2.DataPropertyName = "Name" col2.ToolTipText = "Select something from my combo" Dim dst As New DataSet 'Dim dt1 As New DataTable 'dt1.Columns.Add(col2.HeaderText) 'For Each thing In dt.Rows ' MsgBox(thing(1).ToString) ' dt1.Rows.Add(thing(1).ToString) 'Next dst.Tables.Add(dt) col2.DataSource = dst.Tables(0) col2.DisplayMember = "Name" Me.dgvi00.Columns.AddRange(col2) dgvi00.DataSource = blPersons.BindingSource 'setup the bindings for the binding navigator Dim bn As New _365_Media_Library.BindingNavigatorWithFilter bn.Dock = DockStyle.Bottom bn.GripStyle = ToolStripGripStyle.Hidden Me.Controls.Add(bn) bn.BindingSource = blPersons.BindingSource note : its working good in standalone application regards and thanks sarva

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  • C# Timer -- measuring time slower

    - by Fassenkugel
    I'm writing a code where: I.) The user adds "events" during run-time. (To a flowlayoutpanel) These events are turning some LEDs on/off, after "x" time has elapsed and the LED-turning functions are written in a Led-function.cs class. i.e: 1) Turn left led on After 3500ms 2) Turn right led on After 4000ms II.) When the user hits start a timer starts. // Create timer. System.Timers.Timer _timer; _timer = new System.Timers.Timer(); _timer.Interval = (1); _timer.Elapsed += (sender, e) => { HandleTimerElapsed(LedObject, device, _timer); }; _timer.Start(); III.) The timer's tick event is raised every millisecond and checks if the user definied time has ellapsed. Im measuring the elapsed time with adding +1 to an integer at every tick event. (NumberOfTicks++;) //Timer Handle private void HandleTimerElapsed(Led_Functions LedObject, string device, System.Timers.Timer _timer) { NumberOfTicks++; if (NumberOfTicks >= Start_time[0]) { LedObject.LeftLED_ONnobutton(device); } } IV.) What I noticed was that when the tick was set to 1. (So the tick event is raised every millisecond) Even if I set 3000ms to the evet the LED actually flashed around 6 seconds. When the tick was set to 100. (So every 0,1s) then the flash was more accurate (3,5sec or so). Any Ideas why im having this delay in time? Or do you have any ideas how could I implement it better? Thank you!

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  • Concept: Information Into Memory Location.

    - by Richeve S. Bebedor
    I am having troubles conceptualizing an algorithm to be used to transform any information or data into a specific appropriate and reasonable memory location in any data structure that I will be devising. To give you an idea, I have a JPanel object instance and I created another Container type object instance of any subtype (note this is in Java because I love this language), then I collected those instances into a data structure not specifically just for those instances but also applicable to any type of object. Now my procedure for fetching those data again is to extract the object specific features similar in category to all object in that data structure and transform it into a integer data memory location (specifically as much as possible) or any type of data that will pertain to this transformation. And I can already access that memory location without further sorting or applications of O(n) time complex algorithms (which I think preferable but I wanted to do my own way XD). The data structure is of any type either binary tree, linked list, arrays or sets (and the like XD). What is important is I don't need to have successive comparing and analysis of data just to locate information in big structures. To give you a technical idea, I have to an array DS that contains JLabel object instance with a specific name "HelloWorld". But array DS contains other types of object (in multitude). Now this JLabel object has a location in the array at index [124324] (which is if you do any type of searching algorithm just to arrive at that location is conceivably slow because added to it the data structure used was an array *note please disregard the efficiency of the data structure to be used I just want to explain to you my concept XD). Now I want to equate "HelloWorld" to 124324 by using a conceptually made function applicable to all data types. So that I can do a direct search by doing this DS[extractLocation("HelloWorld")] just to get that JLabel instance. I know this may sound crazy but I want to test my concept of non-sorting feature extracting search algorithm for any data structure wherein my main problem is how to transform information to be stored into memory location of where it was stored.

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  • C++ and its type system: How to deal with data with multiple types?

    - by sub
    "Introduction" I'm relatively new to C++. I went through all the basic stuff and managed to build 2-3 simple interpreters for my programming languages. The first thing that gave and still gives me a headache: Implementing the type system of my language in C++ Think of that: Ruby, Python, PHP and Co. have a lot of built-in types which obviously are implemented in C. So what I first tried was to make it possible to give a value in my language three possible types: Int, String and Nil. I came up with this: enum ValueType { Int, String, Nil }; class Value { public: ValueType type; int intVal; string stringVal; }; Yeah, wow, I know. It was extremely slow to pass this class around as the string allocator had to be called all the time. Next time I've tried something similar to this: enum ValueType { Int, String, Nil }; extern string stringTable[255]; class Value { public: ValueType type; int index; }; I would store all strings in stringTable and write their position to index. If the type of Value was Int, I just stored the integer in index, it wouldn't make sense at all using an int index to access another int, or? Anyways, the above gave me a headache too. After some time, accessing the string from the table here, referencing it there and copying it over there grew over my head - I lost control. I had to put the interpreter draft down. Now: Okay, so C and C++ are statically typed. How do the main implementations of the languages mentioned above handle the different types in their programs (fixnums, bignums, nums, strings, arrays, resources,...)? What should I do to get maximum speed with many different available types? How do the solutions compare to my simplified versions above?

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  • Caching vector addition over changing collections

    - by DRMacIver
    I have the following setup: I have a largish number of uuids (currently about 10k but expected to grow unboundedly - they're user IDs) and a function f : id - sparse vector with 32-bit integer values (no need to worry about precision). The function is reasonably expensive (not outrageously so, but probably on the order of a few 100ms for a given id). The dimension of the sparse vectors should be assumed to be infinite, as new dimensions can appear over time, but in practice is unlikely to ever exceed about 20k (and individual results of f are unlikely to have more than a few hundred non-zero values). I want to support the following operations efficiently: add a new ID to the collection invalidate an existing ID retrieve sum f(id) in O(changes since last retrieval) i.e. I want to cache the sum of the vectors in a way that's reasonable to do incrementally. One option would be to support a remove ID operation and treat invalidation as a remove followed by an add. The problem with this is that it requires us to keep track of all the old values of f, which is expensive in space. I potentially need to use many instances of this sort of cached structure, so I would like to avoid that. The likely usage pattern is that new IDs are added at a fairly continuous rate and are frequently invalidated at first. Ids which have been invalidated recently are much more likely to be invalidated again than ones which have remained valid for a long time, but in principle an old Id can still be invalidated. Ideally I don't want to do this in memory (or at least I want a way that lets me save the result to disk efficiently), so an idea which lets me piggyback off an existing DB implementation of some sort would be especially appreciated.

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  • Displaying data from linked tables in netbeans JTable

    - by Darc
    I have been writing in java for a few months now and have just started using netbeans. I have spent all day today trying to work out how to connect to an SQL database and display data from 2 tables (ie display the data from from a select statement with an inner join) in a JTable. I have tried using JPQL with the following statment SELECT j, cust.name FROM Job j JOIN j.jobnumber cust where the job table has a field called customer that references id in the customer table. This throws the exception: Caused by: Exception [TOPLINK-8029] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EJBQLException Exception Description: Error compiling the query [SELECT j, cust.name FROM Job j JOIN j.jobnumber cust], line 1, column 11: invalid navigation expression [cust.name], cannot navigate expression [cust] of type [java.lang.Integer] inside a query. at oracle.toplink.essentials.exceptions.EJBQLException.invalidNavigation(EJBQLException.java:430) What am i doing wrong? Can anyone point me to some examples of how to make a linked table java application? I am still in the very early stages of development so a complete change is not out of the question if using a mysql database isnt the best way to go about things thanks

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  • Java queue and multi-dimension array

    - by javaLearner.java
    First of all, this is my code (just started learning java): Queue<String> qe = new LinkedList<String>(); qe.add("b"); qe.add("a"); qe.add("c"); qe.add("d"); qe.add("e"); My question: Is it possible to add element to the queue with two values, like: qe.add("a","1"); // where 1 is integer So, that I know element "a" have value 1. If I want to add a number let say "2" to element a, I will have like a = 3. If this cant be done, what else in java classes that can handle this? I tried to use multi-dimention array, but its kinda hard to do the queue, like pop, push etc. (Maybe I am wrong) How to call specific element in the queue? Like, call element a, to check its value. [Note] Please don't give me links that ask me to read java docs. I was reading, and I still dont get it. The reason why I ask here is because, I know I can find the answer faster and easier.

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  • Prolog Beginner: How to unify with arithmentic cmparison operators or how to get a set var to range

    - by sixtyfootersdude
    I am new to prolog. I need to write an integer adder that will add numbers between 0-9 to other numbers 0-9 and produce a solution 0-18. This is what I want to do: add(in1, in2, out) :- in1 < 10, in2 < 10, out < 18. I would like to be able to call it like this: To Check if it is a valid addition: ?- add(1,2,3). true ?- add(1,2,4). false With one missing variable: ?- add(X,2,3). 1 ?- add(1,4,X). 5 With multiple missing variables: ?-add(X,Y,Z). % Some output that would make sense. Some examples could be: X=1, Y=1, Z=2 ; X=2, Y=1, Z=3 ...... I realize that this is probably a pretty simplistic question and it is probably very straightforward. However cording to the prolog tutorial I am using: "Unlike unification Arithmetic Comparison Operators operators cannot be used to give values to a variable. The can only be evaluated when every term on each side have been instantiated."

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  • How to check user input for correct formatting

    - by Arcadian
    This is what i've come up with so far private void CheckFormatting() { StringReader objReaderf = new StringReader(txtInput.Text); List<String> formatTextList = new List<String>(); do { formatTextList.Add(objReaderf.ReadLine()); } while (objReaderf.Peek() != -1); objReaderf.Close(); for (int i = 0; i < formatTextList.Count; i++) { } } What it is designed to do is check that the user has entered their information in this format Gxx:xx:xx:xx JGxx where "x" can be any integer. As you can see the user inputs their data into a multi-line textbox. i then take that data and enter it into a list. the next part is where i'm stuck. i create a for loop to go through the list line by line, but i guess i will also need to go through each line character by character. How do i do this? or is there a faster way of doing it? thanks in advance

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  • How to save enum settings in Visual Studio project properties?

    - by zaidwaqi
    Hi, In the Settings tab in Visual Studio, I can see Name, Type, Scope, Value table. Define settings is intuitive if the data type is already within the Type drop-down list i.e. integer, string, long etc. But I can't find enum anywhere. How do I save enum settings then? For now, I have the following which clutter my code too much. public enum Action { LOCK = 9, FORCED_LOGOFF = 12, SHUTDOWN = 14, REBOOT, LOGOFF = FORCED_LOGOFF }; and I define Action as int in the setting. Then I have to do, switch (Properties.Settings.Default.Action) { case 9: SetAction(Action.LOCK); break; case 12: SetAction(Action.FORCED_LOGOFF); break; case 14: SetAction(Action.SHUTDOWN); break; case 15: SetAction(Action.REBOOT); break; default: SetAction(Action.LOCK); break; } Would be nice if I could simply do something like SetAction(Properties.Settings.Default.Action); to replace all above but I dont know how to save enum in setting. Hope my question is clear. Thanks.

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  • How do I make a lock that allows only ONE thread to read from the resource ?

    - by mare
    I have a file that holds an integer ID value. Currently reading the file is protected with ReaderWriterLockSlim as such: public int GetId() { _fileLock.EnterUpgradeableReadLock(); int id = 0; try { if(!File.Exists(_filePath)) CreateIdentityFile(); FileStream readStream = new FileStream(_filePath, FileMode.Open, FileAccess.Read); StreamReader sr = new StreamReader(readStream); string line = sr.ReadLine(); sr.Close(); readStream.Close(); id = int.Parse(line); return int.Parse(line); } finally { SaveNextId(id); // increment the id _fileLock.ExitUpgradeableReadLock(); } } The problem is that subsequent actions after GetId() might fail. As you can see the GetId() method increments the ID every single time, disregarding what happens after it has issued an ID. The issued ID might be left hanging (as said, exceptions might occur). As the ID is incremented, some IDs might be left unused. So I was thinking of moving the SaveNextId(id) out, remove it (the SaveNextId() actually uses the lock too, except that it's EnterWriteLock). And call it manually from outside after all the required methods have executed. That brings out another problem - multiple threads might enter the GetId() method before the SaveNextId() gets executed and they might all receive the same ID. I don't want any solutions where I have to alter the IDs after the operation, correcting them in any way because that's not nice and might lead to more problems. I need a solution where I can somehow callback into the FileIdentityManager (that's the class that handles these IDs) and let the manager know that it can perform the saving of the next ID and then release the read lock on the file containing the ID. Essentialy I want to replicate the relational databases autoincrement behaviour - if anything goes wrong during row insertion, the ID is not used, it is still available for use but it also never happens that the same ID is issued. Hopefully the question is understandable enough for you to provide some solutions..

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  • iPhone: Same Rows Repeated in Each Section of Grouped UITableview

    - by Rank Beginner
    I have an app that is a list of tasks, like a to do list. The user configures the tasks and that goes to the SQLite db. The list is displayed in a tableview. The SQL table in question consists of a taskid int, groupname varchar, taskname varchar, lastcompleted datetime, nextdue datetime, weighting integer. I currently have it working by creating an array from each column in the SQL table. In the tableView:cellForRowAtIndexPath: method, I create the controls for each task by binding their values to the array for each column. I want to add configurable task groups that should display as the section titles. I got the task groups to display as the section headers. My problem is that all the task rows are repeated in each group under each header. How do I get the correct rows to show up only under the correct section? I'm really new to development period and took on a hobby of trying to teach myself how to develop iphone apps. So, pretty please, be a little more detailed than you normally would with a professional developer. :)

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  • Cannot serialize this List<T> extension

    - by Jaxidian
    I'm trying to push a subset of a collection of data through WCF to be consumed by WCF - think paged data. As such, I want this collection to have one page's worth of data as well as a total number of results. I figured this should be trivial by creating a custom object that extends List. However, everything I do results in my TotalNumber property coming across as 0. All of the data gets serialized/deserialized just fine but that single integer won't come across at all. Here's my first attempt that failed: [Serializable] public class PartialList<T> : List<T> { public PartialList() { } public PartialList(IEnumerable<T> collection) : base(collection) { } [DataMember] public int UnpartialTotalCount { get; set; } And here's my second attempt that failed in the exact same way: [Serializable] public class PartialList<T> : List<T>, ISerializable { public PartialList() { } public PartialList(IEnumerable<T> collection) : base(collection) { } [DataMember] public int UnpartialTotalCount { get; set; } protected PartialList(SerializationInfo info, StreamingContext context) { UnpartialTotalCount = info.GetInt32("UnpartialTotalCount"); } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("UnpartialTotalCount", UnpartialTotalCount); } } What's the deal here??

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  • Else statement crashes when i enter a letter for a cin << int value

    - by TimothyTech
    Alright, i have a question, i veered away from using strings for selection so now i use an integer.when the user enters a number then the game progresses. if they enter a wrong character it SHOULD give the else statement, however if i enter a letter or character the system goes into an endless loop effect then crashes. is there a way to give the else statement even if the user defies the variable's type. // action variable; int c_action: if (c_action == 1){ // enemy attack and user attack with added effect buffer. /////////////////////////////////////////////////////// u_attack = userAttack(userAtk, weapons); enemyHP = enemyHP - u_attack; cout << " charging at the enemy you do " << u_attack << "damage" << endl; e_attack = enemyAttack(enemyAtk); userHP = userHP - e_attack; cout << "however he lashes back causing you to have " << userHP << "health left " << endl << endl << endl << endl; //end of ATTACK ACTION }else{ cout << "invalid actions" << endl; goto ACTIONS; }

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  • Optimize INSERT / UPDATE / DELETE operation

    - by clime
    I wonder if the following script can be optimized somehow. It does write a lot to disk because it deletes possibly up-to-date rows and reinserts them. I was thinking about applying something like "insert ... on duplicate key update" and found some possibilities for single-row updates but I don't know how to apply it in the context of INSERT INTO ... SELECT query. CREATE OR REPLACE FUNCTION update_member_search_index() RETURNS VOID AS $$ DECLARE member_content_type_id INTEGER; BEGIN member_content_type_id := (SELECT id FROM django_content_type WHERE app_label='web' AND model='member'); DELETE FROM watson_searchentry WHERE content_type_id = member_content_type_id; INSERT INTO watson_searchentry (engine_slug, content_type_id, object_id, object_id_int, title, description, content, url, meta_encoded) SELECT 'default', member_content_type_id, web_member.id, web_member.id, web_member.name, '', web_user.email||' '||web_member.normalized_name||' '||web_country.name, '', '{}' FROM web_member INNER JOIN web_user ON (web_member.user_id = web_user.id) INNER JOIN web_country ON (web_member.country_id = web_country.id) WHERE web_user.is_active=TRUE; END; $$ LANGUAGE plpgsql; EDIT: Schemas of web_member, watson_searchentry, web_user, web_country: http://pastebin.com/3tRVPPVi. (content_type_id, object_id_int) in watson_searchentry is unique pair in the table but atm the index is not present (there is no use for it). This script should be run at most once a day for full rebuilds of search index.

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  • C vs C++ function questions

    - by james
    I am learning C, and after starting out learning C++ as my first compiled language, I decided to "go back to basics" and learn C. There are two questions that I have concerning the ways each language deals with functions. Firstly, why does C "not care" about the scope that functions are defined in, whereas C++ does? For example, int main() { donothing(); return 0; } void donothing() { } the above will not compile in a C++ compiler, whereas it will compile in a C compiler. Why is this? Isn't C++ mostly just an extension on C, and should be mostly "backward compatible"? Secondly, the book that I found (Link to pdf) does not seem to state a return type for the main function. I check around and found other books and websites and these also commonly do not specify return types for the main function. If I try to compile a program that does not specify a return type for main, it compiles fine (although with some warnings) in a C compiler, but it doesn't compile in a C++ compiler. Again, why is that? Is it better style to always specify the return type as an integer rather than leaving it out? Thanks for any help, and just as a side note, if anyone can suggest a better book that I should buy that would be great!

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  • Complexity of subset product

    - by threenplusone
    I have a set of numbers produced using the following formula with integers 0 < x < a. f(x) = f(x-1)^2 % a For example starting at 2 with a = 649. {2, 4, 16, 256, 636, 169, 5, 25, 649, 576, 137, ...} I am after a subset of these numbers that when multiplied together equals 1 mod N. I believe this problem by itself to be NP-complete (based on similaries to Subset-Sum problem). However starting with any integer (x) gives the same solution pattern. Eg. a = 649 {2, 4, 16, 256, 636, 169, 5, 25, 649, 576, 137, ...} = 16 * 5 * 576 = 1 % 649 {3, 9, 81, 71, 498, 86, 257, 500, 135, 53, 213, ...} = 81 * 257 * 53 = 1 % 649 {4, 16, 256, 636, 169, 5, 25, 649, 576, 137, 597, ...} = 256 * 25 * 137 = 1 % 649 I am wondering if this additional fact makes this problem solvable faster? Or if anyone has run into this problem previously or has any advice?

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  • Properly obsoleting old members in an XML Serializable class in C# VB .NET

    - by George
    Hi! Some time ago I defined a class that was serialized using XML. That class contained a serializable propertyA of integer type. Now I have extended and updated this class, whereby a new propertyB was added, whose type is another class that also has several serializable properties. The new propertyB is now supposed to play the role of propertyA, that is since type of propertyB is another class, one of its members would contain the value that previously propertyA contained, thus making peroptyA obsolete. What I am trying to figure out is how do I make sure that when I desireliaze the OLD version of this class (without propertyB in it), I make sure that the desreializer would take the value of propertyA from the old calss and set it as a value of one of the members of propertyB in a new class? Private WithEvents _Position As Position = New Position(Alignment.MiddleMiddle, 0, True, 0, True) Public Property Position() As Position 'NEW composite property that holds the value of the obsolted property, i.e. Alignment Get Return _Position End Get Set(ByVal value As Position) _Position = value End Set End Property Private _Alignment As Alignment = Alignment.MiddleMiddle <Xml.Serialization.XmlIgnore(), Obsolete("Use Position property instead.")> _ Public Property Alignment() As Alignment'The old, obsoleted property that I guess must be left for compliance with deserializing the old version of this class Get Return _Alignment End Get Set(ByVal value As Alignment) _Alignment = value End Set End Property Can you help me, please?

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