Search Results

Search found 8776 results on 352 pages for 'boolean logic'.

Page 297/352 | < Previous Page | 293 294 295 296 297 298 299 300 301 302 303 304  | Next Page >

  • C# Possible to have a generic return type?

    - by JL
    Here is a typical function that returns either true/false; private static bool hasValue() { return true; } Now on an error, I would like to return my own custom error object with definition: public class Failure { public string failureDateTime { get; set; } public string failureReason { get; set; } } I would have expected to be able to throw this custom object for example... private static bool hasValue() { throw new Failure(); } This is not possible, and I don't want to derive Failure from System.IO.Exception because of the inability to serialize an exception in C#. What is the best practice / or ideal solution to this problem. Should I just work with private static object? Or is there a cleaner way to return a custom object or bypass the typical return type on an error (not using System.IO.Exception)? Not entirely wild about object either, because then I need to cast the result and validate it by more boolean logic.

    Read the article

  • Beginner Question ; About Prime Generation in "C" - What is wrong with my code ? -

    - by alorsoncode
    I'm a third year irregular CS student and ,i just realized that i have to start coding. I passed my coding classes with lower bound grades so that i haven't a good background in coding&programming. I'm trying to write a code that generates prime numbers between given upper and lower bounds. Not knowing C well, enforce me to write a rough code then go over it to solve. I can easily set up the logic for intended function but i probably create a wrong algorithm through several different ways. Here I share my last code, i intend to calculate that when a number gives remainder Zero , it should be it self and 1 , so that count==2; What is wrong with my implementation and with my solution generating style? I hope you will warm me up to programming world, i couldn't find enough motivation and courage to get deep into programming. Thanks in Advance :) Stdio and Math.h is Included int primegen(int down,int up) { int divisor,candidate,count=0,k; for(candidate=down;candidate<=up;candidate++) { for(divisor=1;divisor<=candidate;divisor++) { k=(candidate%divisor); } if (k==0) count++; if(count==2) { printf("%d\n", candidate); count=0; } else { continue; } } } int main() { primegen(3,15); return 0; }

    Read the article

  • EF 4 Query - Issue with Multiple Parameters

    - by Brian
    Hello, A trick to avoiding filtering by nullable parameters in SQL was something like the following: select * from customers where (@CustomerName is null or CustomerName = @CustomerName) This worked well for me in LINQ to SQL: string customerName = "XYZ"; var results = (from c in ctx.Customers where (customerName == null || (customerName != null && c.CustomerName == customerName)) select c); But that above query, when in ADO.NET EF, doesn't work for me; it should filter by customer name because it exists, but it doesn't. Instead, it's querying all the customer records. Now, this is a simplified example, because I have many fields that I'm utilizing this kind of logic with. But it never actually filters, queries all the records, and causes a timeout exception. But the wierd thing is another query does something similarly, with no issues. Any ideas why? Seems like a bug to me, or is there a workaround for this? I've since switched to extension methods which works. Thanks.

    Read the article

  • [ask][php] find dynamic filename exist

    - by r4ccoon
    hi. i am writing a cache module in php. it tries to write a cache with a $string+timestamp as a filename. i dont have problem with writing the cache. the problem is i do a foreach loop to get the cache that i want. this is the logic that i use for getting the cache foreach ($filenames as $filename){ if(strstr($filename,$cachename)){//if found if(check_timestamp($filename,time())) display_cace($filename); break; } } but when it tries to get and read the cache, it slows the server down. imagine that i have 10000 cache file in a folder, and i need to check for every file in that cache folder. so how do you think the best way of doing this. here i explain again, because even me still dont understand my written question.. :D i write cache file with this format filename_timestamp.. e.g cache_function_random_news_191982899010 in a folder ./cache/ when i want to get the cache, i only pass "cache_function_random_news_" and check recursively on that folder. if i find something with that needle on a file name, display it, and break. but checking recursively on a 10000 files in a folder is not a good thing yeah? please give me your opinion ok, that would clarify more. thanks.

    Read the article

  • Objects leaking immediately from allocation using either new or [[Object alloc] init];

    - by Sam
    While running Instruments to find leaks in my code, after I've loaded a file and populate an NSMutableArray with new objects, leaks pop up! I am correctly releasing the objects. Sample code below: //NSMutableArray declared as a retained property in the parent class if(!mutableArray) mutableArray = [[NSMutableArray alloc] initWithCapacity:objectCount]; else [mutableArray removeAllObjects]; //Iterates through the read in data and populate the NSMutableArray for(int i = 0; i < objectCount; i++){ //Initializes a new object with data MyObject *object = [MyObject new]; //Adds the object to the mutableArray [mutableArray addObject:object]; //Releases the object [object release]; } I get a number of leaks from Instruments terminating at the addition of the 'object' into the 'mutableArray', but also including the allocation of the 'object' and the 'mutableArray'. I don't get it. Not to mention, this is happening on the first call of the enclosing method so the allocation of the NSMutableArray is being hit in the logic block, not the 'removeAllObjects' selector. Lastly, does Core Foundation have a major bug in it that randomly creates CFStrings and mismanages their memory? My code does not even use those, nor do the leaks where they occur have anything to do with my code. Almost all of my applications so far deal with OpenGL (in case anyone knows of a threading issue that arises from trying to synch the backend of the program with the front end of displaying the contents of an NSOpenGLView class or whatever it is).

    Read the article

  • Share variable across site ASP.NET

    - by Anders
    I have a class isSearching with a single boolean property in a 'functions' file in my webapp. On my search page, I have a variable oSearchHandler declared as a Public Shared variable. How can I access the contents of oSearchHandler on other pages in my webapp? Code with Session.... 'search.aspx Public Function oSearchString(ByVal oTextBoxName As String) As String For Each oKey As String In Request.Form.AllKeys If oKey.Contains(oTextBoxName) Then Session.Add("searching", True) Session.Add("search-term", Request.Form(oKey)) Return Request.Form(oKey) End If Next Return "" End Function 'theMaster.master <% If Session("searching") Then %><ul style="float: right;"> <li> <div class="gsSearch"> <asp:TextBox ID="searchbox" runat="server"></asp:TextBox> </div> </li> <li> <div class="gsSearch"> <asp:Button ID="searchbutton" runat="server" Text="search" UseSubmitBehavior="true" PostBackUrl="search.aspx" CssClass="searchBtn" /> </div> </li> </ul> <% End If %> I think that the session will work just fine.

    Read the article

  • Checkbox not working properly for IE with jquery

    - by wildanjel
    Hi, I am trying using several asp.net checkboxes on a page, disabling them accordingly. <asp:CheckBox ID='chkMenuItem' runat='server' CssClass='HiddenText' Text='Test' onclick='<%#String.Format("checkChild({0});", Eval("id")) %>' /> on javascript, I am using the following code function checkChild(id) { for (i = 0; i < $("input[id*=hdnParentMenuItemID]").length; i++) { if ($('input[id*=hdnParentMenuItemID]')[i].value.split(':')[0] == id) { var childID = $('input[id*=hdnParentMenuItemID]')[i].value.split(':')[1]; if ($("#" + childID).attr("disabled")) //$("#" + childID).attr('disabled', ''); $("#" + childID).removeAttr("disabled"); else $("#" + childID).attr('disabled', true); } } } Now is the checkboxes are disabled once the page is loaded, the removeAttr section doesn't work. I tried to step through the debugger and the logic works perfectly fine. If the checkboxes aren't disabled on page load, the code works fine. I tried replacing disabled 'attributes' with 'checked' to see if the other attributes work fine and it works perfectly fine. I tried $("#" + childID).attr('disabled', ''); but it didnt work either. Note: It works perfect on FF and Chrome but doesnt work in IE. Thanks,

    Read the article

  • (Java) Get value of string loaded into dynamic-type object?

    - by Michael
    I'm very new to Java (~10 days), so my code is probably pretty bad, but here's what I've got: ArgsDataHolder argsData = new ArgsDataHolder(); // a class that holds two // ArrayList's where each element // representing key/value args Class thisArgClass; String thisArgString; Object thisArg; for(int i=2; i< argsString.length; i++) { thisToken = argsString[i]; thisArgClassString = getClassStringFromToken(thisToken).toLowerCase(); System.out.println("thisArgClassString: " + thisArgClassString); thisArgClass = getClassFromClassString(thisArgClassString); // find closing tag; concatenate middle Integer j = new Integer(i+1); thisArgString = getArgValue(argsString, j, "</" + thisArgClassString + ">"); thisArg = thisArgClass.newInstance(); thisArg = thisArgClass.valueOf(thisArgString); argsData.append(thisArg, thisArgClass); } The user basically has to input a set of key/value arguments into the command prompt in this format: <class>value</class>, e.g. <int>62</int>. Using this example, thisArgClass would be equal to Integer.class, thisArgString would be a string that read "62", and thisArg would be an instance of Integer that is equal to 62. I tried thisArg.valueOf(thisArgString), but I guess valueOf(<String>) is only a method of certain subclasses of Object. For whatever reason, I can't seem to be able to cast thisArg to thisArgClass (like so: thisArg = (thisArgClass)thisArgClass.newInstance();, at which point valueOf(<String>) should become accessible. There's got to be a nice, clean way of doing this, but it is beyond my abilities at this point. How can I get the value of the string loaded into a dynamically-typed object (Integer, Long, Float, Double, String, Character, Boolean, etc.)? Or am I just overthinking this, and Java will do the conversion for me? :confused:

    Read the article

  • While in a transaction, how can reads to an affected row be prevented until the transaction is done?

    - by Mahn
    I'm fairly sure this has a simple solution, but I haven't been able to find it so far. Provided an InnoDB MySQL database with the isolation level set to SERIALIZABLE, and given the following operation: BEGIN WORK; SELECT * FROM users WHERE userID=1; UPDATE users SET credits=100 WHERE userID=1; COMMIT; I would like to make sure that as soon as the select inside the transaction is issued, the row corresponding to userID=1 is locked for reads until the transaction is done. As it stands now, UPDATEs to this row will wait for the transaction to be finished if it is in process, but SELECTs simply will read the previous value. I understand this is the expected behaviour in this case, but I wonder if there is a way to lock the row in such a way that SELECTs will also wait until the transaction is finished to return the values? The reason I'm looking for that is that at some point, and with enough concurrent users, it could happen that while the previous transaction is in process someone else reads the "credits" to calculate something else. Ideally the code run by that someone else should wait for the transaction to finish to use the new value, because otherwise it could lead to irreversible desync issues. Note that I don't want to lock the entire table for reads, just the specific row. Also, I could add a boolean "locked" field to the tables and set it to 1 every time I'm starting a transaction but I don't really feel this is the most elegant solution here, unless there is absolutely no other way to handle this through mysql directly.

    Read the article

  • Changing PHP variable from an <a href=""> link

    - by aener
    I'm making a site using divs. I have one across the top with a row of links which I want to change what's in the main window. I would prefer to keep strictly to PHP and HTML and use a full page refresh as I am comfortable with them at current, rather than using an Ajax refresh as I don't have any knowledge of Ajax. I don't want to use iframes. I thought the best way to do this would be as follows: <div id="top"> <a href="news.html">News</a> </div> <div id="main"> <?php include($page); ?> </div> What I need is a way of changing the $page variable upon clicking the link. If this means changing the variable and then reloading the page then so be it. A command following the logic of: <a href="news.html" action="<?php $page="news.html"; ?>">News</a> would be ideal! I thought about using a form, but it seems there should be an easier way.

    Read the article

  • Convert one delphi code line to c++

    - by user1332636
    How can I write that line in c++? This is the code in delphi type TSettings = record sFileName: String[50]; siInstallFolder: Byte; bRunFile: Boolean; ... end; .. var i: dword; sZdData: PChar; Settings :Tsettings; begin .... ZeroMemory(@Settings, sizeof(Tsettings)); settings := Tsettings(Pointer(@sZdData[i])^); // this code to c++ c++ code (hope the rest is OK) struct TSettings{ char sFileName[50]; byte siInstallFolder; bool bRunFile; ... } Settings; ... DWORD i; LPBYTE sZdData; ZeroMemory(&Settings, sizeof(TSettings)); Settings = ????? // im failing here i dunno what to do // i need same as in delphi code above

    Read the article

  • Printing distinct integers in an array

    - by ???
    I'm trying to write a small program that prints out distinct numbers in an array. For example if a user enters 1,1,3,5,7,4,3 the program will only print out 1,3,5,7,4. I'm getting an error on the else if line in the function checkDuplicate. Here's my code so far: import javax.swing.JOptionPane; public static void main(String[] args) { int[] array = new int[10]; for (int i=0; i<array.length;i++) { array[i] = Integer.parseInt(JOptionPane.showInputDialog("Please enter" + "an integer:")); } checkDuplicate (array); } public static int checkDuplicate(int array []) { for (int i = 0; i < array.length; i++) { boolean found = false; for (int j = 0; j < i; j++) if (array[i] == array[j]) { found = true; break; } if (!found) System.out.println(array[i]); } return 1; } }

    Read the article

  • Why won't my UITableViewCell deselect and update its text?

    - by Josh
    I have a UITableView with a list of stories and a cell at the bottom that loads more stories. I am trying to make the "More Stories..." cell deselect and change its text to "Loading..." when clicked. I have searched all over the internet and all over stackoverflow and I cant figure out why my code isnt working right. Right now, when the "More Stories..." cell is clicked, it stays selected and doesnt ever change its text. - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { // Navigation logic int storyIndex = [indexPath indexAtPosition: [indexPath length] - 1]; if (storyIndex == [stories count]) { UITableViewCell *moreCell = [tableView dequeueReusableCellWithIdentifier:@"more"]; if (moreCell == nil) { moreCell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"more"] autorelease]; } // Set up the cell moreCell.textLabel.text = @"Loading..."; [tableView deselectRowAtIndexPath:indexPath animated:YES]; [self moreStories]; } else { NSLog(@"%@",[[stories objectAtIndex: storyIndex] objectForKey: @"link"]); webViewController *webController; webController = [[webViewController alloc] initWithURLPassed:[[stories objectAtIndex: storyIndex] objectForKey: @"link"]]; [self.navigationController pushViewController:webController animated:YES]; [webController release]; webController =nil; self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil]; } }

    Read the article

  • Database Tutorial: The method open() is undefined for the type MainActivity.DBAdapter

    - by user2203633
    I am trying to do this database tutorial on SQLite Eclipse: https://www.youtube.com/watch?v=j-IV87qQ00M But I get a few errors at the end.. at db.ppen(); i get error: The method open() is undefined for the type MainActivity.DBAdapter and similar for insert record and close. MainActivity: package com.example.studentdatabase; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import android.app.Activity; import android.app.ListActivity; import android.content.Intent; import android.database.Cursor; import android.os.Bundle; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.Toast; public class MainActivity extends Activity { /** Called when the activity is first created. */ //DBAdapter db = new DBAdapter(this); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button addBtn = (Button)findViewById(R.id.add); addBtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent i = new Intent(MainActivity.this, addassignment.class); startActivity(i); } }); try { String destPath = "/data/data/" + getPackageName() + "/databases/AssignmentDB"; File f = new File(destPath); if (!f.exists()) { CopyDB( getBaseContext().getAssets().open("mydb"), new FileOutputStream(destPath)); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } DBAdapter db = new DBAdapter(); //---add an assignment--- db.open(); long id = db.insertRecord("Hello World", "2/18/2012", "DPR 224", "First Android Project"); id = db.insertRecord("Workbook Exercises", "3/1/2012", "MAT 100", "Do odd numbers"); db.close(); //---get all Records--- /* db.open(); Cursor c = db.getAllRecords(); if (c.moveToFirst()) { do { DisplayRecord(c); } while (c.moveToNext()); } db.close(); */ /* //---get a Record--- db.open(); Cursor c = db.getRecord(2); if (c.moveToFirst()) DisplayRecord(c); else Toast.makeText(this, "No Assignments found", Toast.LENGTH_LONG).show(); db.close(); */ //---update Record--- /* db.open(); if (db.updateRecord(1, "Hello Android", "2/19/2012", "DPR 224", "First Android Project")) Toast.makeText(this, "Update successful.", Toast.LENGTH_LONG).show(); else Toast.makeText(this, "Update failed.", Toast.LENGTH_LONG).show(); db.close(); */ /* //---delete a Record--- db.open(); if (db.deleteRecord(1)) Toast.makeText(this, "Delete successful.", Toast.LENGTH_LONG).show(); else Toast.makeText(this, "Delete failed.", Toast.LENGTH_LONG).show(); db.close(); */ } private class DBAdapter extends BaseAdapter { private LayoutInflater mInflater; //private ArrayList<> @Override public int getCount() { return 0; } @Override public Object getItem(int arg0) { return null; } @Override public long getItemId(int arg0) { return 0; } @Override public View getView(int arg0, View arg1, ViewGroup arg2) { return null; } } public void CopyDB(InputStream inputStream, OutputStream outputStream) throws IOException { //---copy 1K bytes at a time--- byte[] buffer = new byte[1024]; int length; while ((length = inputStream.read(buffer)) > 0) { outputStream.write(buffer, 0, length); } inputStream.close(); outputStream.close(); } public void DisplayRecord(Cursor c) { Toast.makeText(this, "id: " + c.getString(0) + "\n" + "Title: " + c.getString(1) + "\n" + "Due Date: " + c.getString(2), Toast.LENGTH_SHORT).show(); } public void addAssignment(View view) { Intent i = new Intent("com.pinchtapzoom.addassignment"); startActivity(i); Log.d("TAG", "Clicked"); } } DBAdapter code: package com.example.studentdatabase; public class DBAdapter { public static final String KEY_ROWID = "id"; public static final String KEY_TITLE = "title"; public static final String KEY_DUEDATE = "duedate"; public static final String KEY_COURSE = "course"; public static final String KEY_NOTES = "notes"; private static final String TAG = "DBAdapter"; private static final String DATABASE_NAME = "AssignmentsDB"; private static final String DATABASE_TABLE = "assignments"; private static final int DATABASE_VERSION = 2; private static final String DATABASE_CREATE = "create table if not exists assignments (id integer primary key autoincrement, " + "title VARCHAR not null, duedate date, course VARCHAR, notes VARCHAR );"; private final Context context; private DatabaseHelper DBHelper; private SQLiteDatabase db; public DBAdapter(Context ctx) { this.context = ctx; DBHelper = new DatabaseHelper(context); } private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { try { db.execSQL(DATABASE_CREATE); } catch (SQLException e) { e.printStackTrace(); } } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS contacts"); onCreate(db); } } //---opens the database--- public DBAdapter open() throws SQLException { db = DBHelper.getWritableDatabase(); return this; } //---closes the database--- public void close() { DBHelper.close(); } //---insert a record into the database--- public long insertRecord(String title, String duedate, String course, String notes) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_TITLE, title); initialValues.put(KEY_DUEDATE, duedate); initialValues.put(KEY_COURSE, course); initialValues.put(KEY_NOTES, notes); return db.insert(DATABASE_TABLE, null, initialValues); } //---deletes a particular record--- public boolean deleteContact(long rowId) { return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0; } //---retrieves all the records--- public Cursor getAllRecords() { return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE, KEY_DUEDATE, KEY_COURSE, KEY_NOTES}, null, null, null, null, null); } //---retrieves a particular record--- public Cursor getRecord(long rowId) throws SQLException { Cursor mCursor = db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE, KEY_DUEDATE, KEY_COURSE, KEY_NOTES}, KEY_ROWID + "=" + rowId, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } //---updates a record--- public boolean updateRecord(long rowId, String title, String duedate, String course, String notes) { ContentValues args = new ContentValues(); args.put(KEY_TITLE, title); args.put(KEY_DUEDATE, duedate); args.put(KEY_COURSE, course); args.put(KEY_NOTES, notes); return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0; } } addassignment code: package com.example.studentdatabase; public class addassignment extends Activity { DBAdapter db = new DBAdapter(this); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.add); } public void addAssignment(View v) { Log.d("test", "adding"); //get data from form EditText nameTxt = (EditText)findViewById(R.id.editTitle); EditText dateTxt = (EditText)findViewById(R.id.editDuedate); EditText courseTxt = (EditText)findViewById(R.id.editCourse); EditText notesTxt = (EditText)findViewById(R.id.editNotes); db.open(); long id = db.insertRecord(nameTxt.getText().toString(), dateTxt.getText().toString(), courseTxt.getText().toString(), notesTxt.getText().toString()); db.close(); nameTxt.setText(""); dateTxt.setText(""); courseTxt.setText(""); notesTxt.setText(""); Toast.makeText(addassignment.this,"Assignment Added", Toast.LENGTH_LONG).show(); } public void viewAssignments(View v) { Intent i = new Intent(this, MainActivity.class); startActivity(i); } } What is wrong here? Thanks in advance.

    Read the article

  • How do I code a tree of objects in Haskell with pointers to parent and children?

    - by axilmar
    I've got the following problem: I have a tree of objects of different classes where an action in the child class invalidates the parent. In imperative languages, it is trivial to do. For example, in Java: public class A { private List<B> m_children = new LinkedList<B>(); private boolean m_valid = true; public void invalidate() { m_valid = false; } public void addChild(B child) { m_children.add(child); child.m_parent = this; } } public class B { public A m_parent = null; private int m_data = 0; public void setData(int data) { m_data = 0; m_parent.invalidate(); } } public class Main { public static void main(String[] args) { A a = new A(); B b = new B(); b.setData(0); //invalidates A } } How do I do the above in Haskell? I cannot wrap my mind around this, since once I construct an object in Haskell, it cannot be changed. I would be much obliged if the relevant Haskell code is posted.

    Read the article

  • More than one unique key for HashMap problem (Java)

    - by Alex Cheng
    This question is a continuation of this thread: In short: To solve my problem, I want to use Map<Set<String>, String>. However, after I sort my data entries in Excel, remove the unnecessary parameters, and the following came out: flow content ==> content content flow content ==> content depth distance flow content ==> content depth within flow content ==> content depth within distance flow content ==> content within flow content ==> content within distance I have more than one unique key for the hashmap if that is the case. How do I go around this... anyone have any idea? I was thinking of maybe Map<Set <String>, List <String>> so that I can do something like: Set <flow content>, List <'content content','content depth distance','content depth within ', ..., 'content within distance'> But because I am parsing the entries line by line I can't figure out the way how to store values of the same repeated keys (flow content) into the same list and add it to the map. Anyone have a rough logic on how can this be done in Java? Thanks in advance.

    Read the article

  • understanding and implementing Boids

    - by alphablender
    So I'm working on porting Boids to Brightscript, based on the pseudocode here: http://www.kfish.org/boids/pseudocode.html I'm trying to understand the data structures involved, for example is Velocity a single value, or is it a 3D value, ie velocity={x,y,z} It seems as if the pseudocode seems to mix this up where sometimes it has an equation that incudes both vectors and single-value items: v1 = rule1(b) v2 = rule2(b) v3 = rule3(b) b.velocity = b.velocity + v1 + v2 + v3 If Velocity is a tripartite value then this would make sense, but I'm not sure. So my first question here is, is this the correct datastructure for a single boid based on the Pseudocode on that page: boid={position:{px:0,py:0,pz:0},velocity:{x:0,y:0,z:0},vector:{x:0,y:0,z:0},pc:{x:0,y:0,z:0},pv:{x:0,y:0,z:0}) where pc=perceived center, pv= perceived velocity I"ve implemented a vector_add, vector_sub, vector_div, and vector boolean functions. The reason I'm starting from this pseudocode is I've not been able to find anything else that is as readable, but it still leaves me with lots of questions as the data structures are not explicitly defined for each variable. (edit) here's a good example of what i'm talking about: IF |b.position - bJ.position| < 100 THEN if b.position - b[j].position are both 3D coordinates, how can they be considered "less than 100" unless they are < {100,100,100} ? Maybe that is what I need to do here, use a vector comparison function?

    Read the article

  • self-destructing objects in php5?

    - by user151841
    I am working on a class in php that is basically an interface to a database row. I wanted to create a delete() method that would 1. delete the database row and 2. destroy the instance of itself so that further attempts to manipulate the row via the object would throw warnings. Doing some googling, it seems that, in php5, it's not possible for an object to unset itself. http://bugs.php.net/bug.php?id=36971 In fact they discuss the very situation I was wanting to do :( So how should I proceed? I could make boolean flag as a class property, for whether the row still exists, and have each operation check that flag and throw an error if the row has been deleted. This maintains the oo structure of code, so I would have $objDbRow->delete(); But then I have to put checks at the beginning of each method. Or, I could implement a __destruct method that deletes the row. But that would seem counter-intuitive to me; if I saw in code unset($objDbRow); All I would suspect that's happening is that the object is being discarded, not that a row is being deleted. So that to me would seem like bad practice.

    Read the article

  • Flash Builder 4 "includeIn" property causing design view error

    - by Chris
    I am creating a custom TextInput component that will define an "error" state. I have extended the TextInput class to change the state to "error" if the errorString property's length is greater than 0. In the skin class, I have defined an "error" state, and added some logic to detect the size and position of the error icon. However, if I have this code at the same time I use the "includeIn" property in the bitmap image tag, I get a design view error. If I either A) Only include that code with no "includeIn" property set, it works or B) dont include the code to set the icon size and position and only use the "includeIn" property, it works. Any ideas what could be causing the design view problem when I use both the "includeIn" property and the icon size/position code at the same time? TextInput Class: package classes { import spark.components.TextInput; public class TextInput extends spark.components.TextInput { [SkinState("error")]; public function TextInput() { super(); } override public function set errorString( value:String ):void { super.errorString = value; invalidateSkinState(); } override protected function getCurrentSkinState():String { if (errorString.length>0) { return "error"; } return super.getCurrentSkinState(); } } } TextInput Skin File: override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void { //THIS IS THE CODE THAT SEEMS TO BE CAUSING THE PROBLEM if(getStyle("iconSize") == "large") { errorIcon.right = -12; errorIcon.source = new errorIconLg(); } else { errorIcon.right = -5; errorIcon.source = new errorIconSm(); } super.updateDisplayList(unscaledWidth, unscaledHeight); } </fx:Script> <s:states> <s:State name="normal"/> <s:State name="disabled"/> <s:State name="error"/> </s:states> //If I remove the problem code above or if I take out the includeIn //property here, it works <s:BitmapImage id="errorIcon" verticalCenter="0" includeIn="error" /> </s:SparkSkin>

    Read the article

  • ASP.NET MVC Search

    - by Cameron
    Hi I'm building a very simple search system using ASP.NET MVC. I had it originally work by doing all the logic inside the controller but I am now moving the code piece by piece into a repository. Can anyone help me do this. Thanks. Here is the original Action Result that was in the controller. public ActionResult Index(String query) { var ArticleQuery = from m in _db.ArticleSet select m; if (!string.IsNullOrEmpty(query)) { ArticleQuery = ArticleQuery.Where(m => m.headline.Contains(query) orderby m.posted descending); } return View(ArticleQuery.ToList()); } As you can see, the Index method is used for both the initial list of articles and also for the search results (they use the same view). In the new system the code in the controller is as follows: public ActionResult Index() { return View(_repository.ListAll()); } The Repository has the following code: public IList<Article> ListAll() { var ArticleQuery = (from m in _db.ArticleSet orderby m.posted descending select m); return ArticleQuery.ToList(); } and the Interface has the following code: public interface INewsRepository { IList<Article> ListAll(); } So what I need to do is now add in the search query stuff into the repository/controller methods using this new way. Can anyone help? Thanks.

    Read the article

  • .Net forms - intercepting the Close X event.

    - by Hamish Grubijan
    Hi, this must be a dumb question, but I cannot figure it out. I also cannot use the designer because coders before me managed to throw GUI and logic all in one, so now it is confused. I've got to do it the old school way. I have a Form which can be closed in 3 ways: Close button, File / Close menu, and the X icon. I want them all to do the same thing. Intercepting the button and the menu events is easy. In fact, both are hooked up to an onCloseConfig method. Btw, is there a better name for this method? private void onCloseConfig(object sender, System.EventArgs e) { if (! m_configControl.Modified) { Application.Exit(); // Or should it be this.Close(); } .... // Else present a dialog, ask if they want to save. } So, to intercept the X I tried: this.FormClosing +=new FormClosingEventHandler(this.onCloseConfig); I believe this is what causes an infinite loop. I do not want that :) FormClosed is another option, but it seems too late. I just want to intercept the fact that the X was clicked, not the fact that the form is closing. Please help. Thanks!

    Read the article

  • How to stop calling the Activity again when device orientation is changed??

    - by user1460323
    My app uses Barcode Scanner. I want to launch the scanner when I open the app so I have it in the onCreate method. The problem is that if I have it like that, when I turn the device it calls again onCreate and calls another scanner. Also I have the first activity that calls the scanner. it has a menu so if he user presses back, it goes to that menu. If I turn the screen on that menu, it goes to barcode scanner again. To solve it I have a flag that indicates if it is the first time I call the scanner, if it's not I don't call it again. Now the problem is that if I go out of the app and go in again it doesn't go to the scanner, it goes to the menu, becasuse is not the first time I call it. Any ideas?? Is there a way to change the flag when I go out of my main activity or any other solution?? My code. private static boolean first = true; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); integrator = new IntentIntegrator(this); if (first) { first = false; integrator.initiateScan(); } }

    Read the article

  • Rails from with better url

    - by Sam
    wow, switching to rest is a different paradigm for sure and is mainly a headache right now. view <% form_tag (businesses_path, :method => "get") do %> <%= select_tag :business_category_id, options_for_select(@business_categories.collect {|bc| [bc.name, bc.id ]}.insert(0, ["All Containers", 0]), which_business_category(@business_category) ), { :onchange => "this.form.submit();"} %> <% end %> controller def index @business_categories = BusinessCategory.find(:all) if params[:business_category_id].to_i != 0 @business_category = BusinessCategory.find(params[:business_category_id]) @businesses = @business_category.businesses else @businesses = Business.all end respond_to do |format| format.html # index.html.erb format.xml { render :xml => @businesses } end end routes map.resources What I want to to is get a better url than what this form is presenting which is the following: http://localhost:3000/businesses?business_category_id=1 Without rest I would have do something like http://localhost:3000/business/view/bbq bbq as permalink or I would have done http://localhost:300/business_categories/view/bbq and get the business that are associated with the category but I don't really know the best way of doing this. So the two questions are what is the best logic of finding a business by its categories using the latter form and number two how to get that in a pretty url all through restful routes in rails.

    Read the article

  • Java Socket Closes After Connection?

    - by Matthew
    Why does this port/socket close once a connection has been made by a client? package app; import java.io.*; import java.net.*; public class socketServer { public static void main(String[] args) { int port = 3333; boolean socketBindedToPort = false; try { ServerSocket ServerSocketPort = new ServerSocket(port); System.out.println("SocketServer Set Up on Port: " + port); socketBindedToPort = true; if(socketBindedToPort == true) { Socket clientSocket = null; try { clientSocket = ServerSocketPort.accept();//This method blocks until a socket connection has been made to this port. System.out.println("Waiting for client connection on port:" + port); /** THE CLIENT HAS MADE A CONNECTION **/ System.out.println("CLIENT IS CONENCTED"); } catch (IOException e) { System.out.println("Accept failed: " + port); System.exit(-1); } } else { System.out.println("Socket did not bind to the port:" + port); } } catch(IOException e) { System.out.println("Could not listen on port: " + port); System.exit(-1); } } }

    Read the article

  • webview in tabhost

    - by user1905845
    I am new to android. I am using webview inside tabview. In my app in first activity facebook button available.when click facebook button connect to facebook in second activity inside tabs fine.In second activity i am using webview. this is the code. public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.facebook); wvFacebook=(WebView)findViewById(R.id.webview); btnBack=(Button)findViewById(R.id.back); txtBarname=(TextView)findViewById(R.id.barnameheader); if(check==1){ strFacebook=MyBarsActivity.strFacebook; Log.e("Facebook url",strFacebook); strBarName=MyBarsActivity.strBarName; } wvFacebook.setWebViewClient(new MyWebViewClient()); wvFacebook.loadUrl(strFacebook); } private class MyWebViewClient extends WebViewClient { public boolean shouldOverrideUrlLoading(WebView view, String url) { view.getSettings().setJavaScriptEnabled(true); view.loadUrl(url); return true; } @Override public void onPageStarted(WebView view, String url, Bitmap favicon) { super.onPageStarted(view, url, favicon); // progressDialog.show(getParent(), "In progress", "Loading, please wait..."); } public void onPageFinished(WebView view, String url) { super.onPageFinished(view, url); } But my problem is when i click connect button facebook page will be displayed well inside tabs.But when i click emial or username and password button it is not responding.Why it is not responding please help me regarding this.thanks in advance.

    Read the article

< Previous Page | 293 294 295 296 297 298 299 300 301 302 303 304  | Next Page >