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  • How to add a checkbox for each row in Rails 3.2 index page?

    - by user938363
    We would like to add a checkbox to each row on Rails index page to flag for the row. This checkbox is not part of the object (no checkbox boolean in database). When the index page shows, a user can check the box to trigger an event for the row in following process: #objects/checkbox_index.html.erb <table> <tr> <th>CheckBox</th> <th>Object Name</th> <th>Object ID</th> </tr> <%= @objects.each do |obj| %> <tr> <td><%= checkbox %></td> <td><%= obj.name %></td> <td><%= obj.id %></td> </tr> <% end %> </table> In controller, the process will be like this: @objects.each do |obj| some_event if obj.checked end There are a couple of questions we don't quite understand: 1. How to declare an array checkbox variable on the form and link it to each row of obj? We have been using `attr_accessor` to declare var for a form. 2. How to retrieve each row on checkbox_index form and pass them back to controller? We are using simple_form for new/edit. Can anyone point me towards any good examples of this sort of behavior, or suggest what we should be thinking about? Many Thanks.

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  • Iterating Through N Level Children

    - by bobber205
    This seems like something neat that might be "built into" jQuery but I think it's still worth asking. I have a problem where that can easily be solved by iterating through all the children of a element. I've recently discovered I need to account for the cases where I would need to do a level or two deeper than the "1 level" (just calling .children() once) I am currently doing. jQuery.each(divToLookAt.children(), function(index, element) { //do stuff } ); This is what I'm current doing. To go a second layer deep, I run another loop after doing stuff code for each element. jQuery.each(divToLookAt.children(), function(index, element) { //do stuff jQuery.each(jQuery(element).children(), function(indexLevelTwo, elementLevelTwo) { //do stuff } ); } ); If I want to go yet another level deep, I have to do this all over again. This is clearly not good. I'd love to declare a "level" variable and then have it all take care of. Anyone have any ideas for a clean efficient jQueryish solution? Thanks!

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  • Second user-defined function returns garbage value?

    - by mintyfresh
    I have been teaching myself C programming, and I've come to a difficult point with using variables across functions. When, I compile this program and run it, the function askBirthYear returns the correct value, but sayAgeInYears returns either 0 or a garbage value. I believe it has something to do with how I used the variable birthYear, but I'm stumped on how to fix the issue. Here is the code: #include <stdio.h> #include <stdlib.h> int askBirthYear(int); void sayAgeInYears(int); int birthYear; int main(void) { askBirthYear(birthYear); sayAgeInYears(birthYear); return EXIT_SUCCESS; } void askBirthYear(int birthYear) { printf("Hello! In what year were you born?\n"); scanf("%d", &birthYear); printf("Your birth year is %d.\n", birthYear); return birthYear; } void sayAgeInYears(int birthYear) { int age; age = 2012 - birthYear; printf("You are %d years old.\n", age); }

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  • find a duplicate series in SQL

    - by SomeMiscGuy
    I have a table with 3 columns containing a variable number of records based off of the first column which is a foreign key. I am trying to determine if I can detect when there is a duplicate across multiple rows for an entire series declare @finddupseries table ( portid int, asset_id int, allocation float ) ; INSERT INTO @finddupseries SELECT 250, 6, 0.05 UNION ALL SELECT 250, 66, 0.8 UNION ALL SELECT 250, 2, 0.105 UNION ALL SELECT 250, 4, 0.0225 UNION ALL SELECT 250, 5, 0.0225 UNION ALL SELECT 251, 13, 0.6 UNION ALL SELECT 251, 2, 0.3 UNION ALL SELECT 251, 5, 0.1 UNION ALL SELECT 252, 13, 0.8 UNION ALL SELECT 252, 2, 0.15 UNION ALL SELECT 252, 5, 0.05 UNION ALL SELECT 253, 13, 0.4 UNION ALL SELECT 253, 2, 0.45 UNION ALL SELECT 253, 5, 0.15 UNION ALL SELECT 254, 6, 0.05 UNION ALL SELECT 254, 66, 0.8 UNION ALL SELECT 254, 2, 0.105 UNION ALL SELECT 254, 4, 0.0225 UNION ALL SELECT 254, 5, 0.0225 select * from @finddupseries The records for portid 250 and 254 match. Is there any way I can write a query to detect this? edit: yes, the entire series must match. Also, if there was a way to determine which one it DID match would be helpful as the actual table has around 10k records. thanks!

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  • What happens with $q.all() when some calls work and others fail?

    - by Alan
    What happens with $q.all() when some calls work and others fail? I have the following code: var entityIdColumn = $scope.entityType.toLowerCase() + 'Id'; var requests = $scope.grid.data .filter(function (rowData, i) { return !angular.equals(rowData, $scope.grid.backup[i]); }) .map(function (rowData, i) { var entityId = rowData[entityIdColumn]; return $http.put('/api/' + $scope.entityType + '/' + entityId, rowData); }); $q.all(requests).then(function (allResponses) { //if all the requests succeeded, this will be called, and $q.all will get an //array of all their responses. console.log(allResponses[0].data); }, function (error) { //This will be called if $q.all finds any of the requests erroring. var abc = error; var def = 99; }); When all of the $http calls work then the allResponses array is filled with data. When one fails the it's my understanding that the second function will be called and the error variable given details. However can someone help explain to me what happens if some of the responses work and others fail?

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  • What's best performance way to constantly change image on WP7?

    - by AlRodriguez
    I'm trying to make my own type of remote desktop for WP7. I have a WCF service that returns an image on what's on the target machine's screen. Here's the WCF Server Code: // Method to load desktop image Bitmap image = new Bitmap( ViewSize.Width, ViewSize.Height ); Graphics g = Graphics.FromImage( image ); g.CopyFromScreen( Position.X, Position.Y, 0, 0, ViewSize ); g.Dispose( ); return image; // Convert image to byte[] which is returned to client using ( MemoryStream ms = new MemoryStream( ) ) { Bitmap image = screenGrabber.LoadScreenImage( ); image.Save( ms, ImageFormat.Jpeg ); imageArray = ms.ToArray( ); } Here's the code for the WP7 client: MemoryStream stream = new MemoryStream( data ); BitmapImage image = new BitmapImage( ); image.SetSource( stream ); BackgroundImage.Source = image; The BackgroundImage variable is an Image control. I'm noticing this freeze on the emulator after a short while, and will eventually crash from an OutOfMemoryException. This is already pretty slow ( images show up a good half second later than what's on the screen ), and I'm wondering if there's a better/faster way of doing this? Any help would be great. Thanks in advance.

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  • login script in php using session variables

    - by kracekumar
    ? username: '; } else { $user=$_POST['user']; $query="select name from login where name='$user'"; $result=mysql_query($query) or die(mysql_error()); $rows=mysql_num_rows($result)or die(mysql_error()); session_start(); //echo "results"; $username=mysql_fetch_array($result) or die(mysql_error()); $fields=mysql_num_fields($result) or die(mysql_error()); echo "username:$username[0]"; $_SESSION['username']=$username[0]; $sesion_username=$_SESSION['username']; //echo "rows:$rows"." "."fields:$fields"; echo""."username:$sesion_username"; } ? i wanted to create a site where user can login and upload their details depending on their user name have stored their details in a database,the problem i am facing is two people 'a' and 'b' login one after other session_variable $_SESSION['username'] will have 'b's' username ,so i can't display 'a's' details now. . . . what i want to achieve is when a user logins in i want to store his name and other details in session variable and navigate him according and display his details

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  • Using Moq to Validate Separate Invocations with Distinct Arguments

    - by Thermite
    I'm trying to validate the values of arguments passed to subsequent mocked method invocations (of the same method), but cannot figure out a valid approach. A generic example follows: public class Foo { [Dependency] public Bar SomeBar { get; set; } public void SomeMethod() { this.SomeBar.SomeOtherMethod("baz"); this.SomeBar.SomeOtherMethod("bag"); } } public class Bar { public void SomeOtherMethod(string input) { } } public class MoqTest { [TestMethod] public void RunTest() { Mock<Bar> mock = new Mock<Bar>(); Foo f = new Foo(); mock.Setup(m => m.SomeOtherMethod(It.Is<string>("baz"))); mock.Setup(m => m.SomeOtherMethod(It.Is<string>("bag"))); // this of course overrides the first call f.SomeMethod(); mock.VerifyAll(); } } Using a Function in the Setup might be an option, but then it seems I'd be reduced to some sort of global variable to know which argument/iteration I'm verifying. Maybe I'm overlooking the obvious within the Moq framework?

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  • method works fine, until it is called in a function, then UnboundLocalError

    - by user1776100
    I define a method called dist, to calculate the distance between two points which I does it correctly when directly using the method. However, when I get a function to call it to calculate the distance between two points, I get UnboundLocalError: local variable 'minkowski_distance' referenced before assignment edit sorry, I just realised, this function does work. However I have another method calling it that doesn't. I put the last method at the bottom This is the method: class MinkowskiDistance(Distance): def __init__(self, dist_funct_name_str = 'Minkowski distance', p=2): self.p = p def dist(self, obj_a, obj_b): distance_to_power_p=0 p=self.p for i in range(len(obj_a)): distance_to_power_p += abs((obj_a[i]-obj_b[i]))**(p) minkowski_distance = (distance_to_power_p)**(1/p) return minkowski_distance and this is the function: (it basically splits the tuples x and y into their number and string components and calculates the distance between the numeric part of x and y and then the distance between the string parts, then adds them. def total_dist(x, y, p=2, q=2): jacard = QGramDistance(q=q) minkowski = MinkowskiDistance(p=p) x_num = [] x_str = [] y_num = [] y_str = [] #I am spliting each vector into its numerical parts and its string parts so that the distances #of each part can be found, then summed together. for i in range(len(x)): if type(x[i]) == float or type(x[i]) == int: x_num.append(x[i]) y_num.append(y[i]) else: x_str.append(x[i]) y_str.append(y[i]) num_dist = minkowski.dist(x_num,y_num) str_dist = I find using some more steps #I am simply adding the two types of distance to get the total distance: return num_dist + str_dist class NearestNeighbourClustering(Clustering): def __init__(self, data_file, clust_algo_name_str='', strip_header = "no", remove = -1): self.data_file= data_file self.header_strip = strip_header self.remove_column = remove def run_clustering(self, max_dist, p=2, q=2): K = {} #dictionary of clusters data_points = self.read_data_file() K[0]=[data_points[0]] k=0 #I added the first point in the data to the 0th cluster #k = number of clusters minus 1 n = len(data_points) for i in range(1,n): data_point_in_a_cluster = "no" for c in range(k+1): distances_from_i = [total_dist(data_points[i],K[c][j], p=p, q=q) for j in range(len(K[c]))] d = min(distances_from_i) if d <= max_dist: K[c].append(data_points[i]) data_point_in_a_cluster = "yes" if data_point_in_a_cluster == "no": k += 1 K[k]=[data_points[i]] return K

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  • How to use strtok in C properly so there is no memory leak?

    - by user246392
    I am somewhat confused by what happens when you call strtok on a char pointer in C. I know that it modifies the contents of the string, so if I call strtok on a variable named 'line', its content will change. Assume I follow the bellow approach: void function myFunc(char* line) { // get a pointer to the original memory block char* garbageLine = line; // Do some work // Call strtok on 'line' multiple times until it returns NULL // Do more work free(garbageLine); } Further assume that 'line' is malloced before it is passed to myFunc. Am I supposed to free the original string after using strtok or does it do the job for us? Also, what happens if 'line' is not malloced and I attempt to use the function above? Is it safer to do the following instead? (Assume the programmer won't call free if he knows the line is not malloced) Invocation char* garbageLine = line; myFunc(line); free(garbageLine); Function definition void function myFunc(char* line) { // Do some work // Call strtok on 'line' multiple times until it returns NULL // Do more work }

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  • MySQL Table Loop using PHP

    - by JM4
    I have an online form which collects consumer data and stores in a dedicated MySQL database. In some instances, data is passed in the URL under the "RefID" variable which is also stored in the database and attached to each registration. I use the 'mysql_num_rows ($result)' to fetch all agent details on another page but this only returns ALL available details. My goal is as follows: GOAL I want to create an HTML table in which rows are automatically generated based on the list of all registrations on my site. A new row is created IF and ONLY IF a unique RefID is present on that particular record. In the event the field is NULL, it is reported on a single line. In short, the HTML table could look something like this: RefID - Number of Enrollments abc123 - 10 baseball - 11 twonk - 7 NULL - 33 Where abc123 is a particular RefID and 10 is the number of times that RefID appears in the DB. If a new registration comes in with RefID = "horses", a new row is created, showing "horses - 1". The HTML table will be viewable by account administrators needing to see the number of enrollments for a particular RefID (which they won't know ahead of time). Anybody have any suggestions?

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  • UserControlArray in Specific ButtonControlArray in C#

    - by Phanindar
    I am new to C#.I have been thinking of adding a ButtonControlArray where i can store each button control.Here is part of my code.I am creating a 6*6 array of button Control. ButtonControl buttonControl; ButtonControl[,] arrayButtons = new ButtonControl[6,6]; public void createGrid() { l = 0; for (int i = 0; i < numberOfButtons; i++) { for (int k = 0; k < numberOfButtons; k++) { buttonControl = new ButtonControl(); buttonControl.Location = new Point(l,j); j += 55; arrayButtons[i, k] = buttonControl; //After the above statement if i print Console.WriteLine(""+arrayButtons[i,k]); i am getting only my projectname.buttoncontrol myGridControl.Controls.Add(buttonControl); } l += 55; j = 10; } } I want to access each variable in arrayButtons[][]..like in a 3*3 matrix..if i want 2nd row 1 column element..then i get something like arrayname[2][1]..same way if i want 2nd button in 2nd row how can i get..i tried doing one way but i couldnt figure it out...Can you help me out with this..

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  • Problems while trying to make a query with variables in the conditions (stored procedure)

    - by pablo89
    Hi!! Im having a problem, Im trying to do a query... I remember that in the past I did something like this but today this query is returning nothing, no error, no data, just nothing... the query is something like this: SELECT field1, @variableX:=field2 FROM table WHERE (SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=0)0 AND (SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=4)=0; I also tried this query but it didnt work (also it gaves no error): SELECT field1, @variableX:=field2, @variableY:=(SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=0), @variableZ:=(SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=4) FROM table WHERE @variableY0 AND @variableZ=0; As you can see, what Im trying to do in the 1st query is use a variable in the conditions; in the 2nd query Im trying to create some variables and evaluate them in the conditions. At the end in the 2nd query the @variableY=1 AND @variableZ=0 but I dont know what the query returns an empty data What could be wrong here??? Any comment or suggest is welcome!!! thanks!!! Bye!!!

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  • getting (this) at different function

    - by twen_ta
    I have couple of input fields with the class "link". All of them should start the jqueryUI dialog so this is why I bind the method to a class and not an single id. The difficulty is now that i can't use the (this) in line 12, because that gives me the identity of the dialog and not the input element. As I am an beginner I don't know how to pass a variable to this event with the element of the input field. What I want to archive is that the dialog should start from the input field and should write the result back to that input field. 1. // this is the click event for the input-field class called "link" 2. $('.link') 3. .button() 4. .click(function() { 5. $('#dialog-form').dialog('open'); 6. 7. }); 8. 9. //this is an excerpt from the opened dialog box and the write back to the input field 10. $("#dialog-form").dialog({ 11. if (bValid) { 12. $('.link').val('' + 14. name.val() + ''); 15. $(this).dialog('close'); 16. } 17. });

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  • multiple touches: touchend event fired only when a touchmove occurs

    - by dridri
    I would like to add some multitouch features to my javascript application when it is accessed from an ios device (and maybe android later). I want to provide a shiftkey-like functionality: the user may hold a button on the screen with one finger, and while this button is pressed, the behavior for a tap action on the rest of the screen is slightly different from the classic tap. The problem i'm running into is that i do not receive any touchend event for the tapping finger unless a touchmove is fired for the first finger holding the shiftkey button. Because the screen is very sensitive, touchmove events gets easily fired and in most cases everything works fine. But when the user's finger is a bit too still, the tapping is not detected until the user moves his finger a bit. This induces a variable 'delay' between the tapping and the action that occurs on the screen (the delay may vary and last a few seconds if the user is very calm). My guess is that this delay will cause the user to tap again and thus fire the action a second time, which is something that i don't want ! You can test it here with your ipad/iphone : http://jsfiddle.net/jdeXH/8/ Try to make the body remain green for a few seconds by holding your finger very still on the cyan div while tapping on the red div. Is this behavior to be expected ? Is there some known workaround for the problem ? I would have expected the touchend event to be fired right away when the finger is removed from the screen. i tested this with iOS 5.1.1 (ipad1 and iphone4s) edit: found a similar question Multitouch touchEvents not triggered as they should on Safari Mobile

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  • Basic Ajax Cache Issue

    - by michaelespinosa
    I have a single page that I need to on occasion asynchronously check the server to see if the status of the page is current (basically, Live or Offline). You will see I have a function with a var live that is set when the page initially loads. I then do an ajax request to the server to retrieve whether the status of live is true or false. I compare the initial live variable with the newly returned data json object. If they're the same I do nothing, but if there different I apply some css classes. I recursively run it with setTimeout (Is there a better way to recursively do this?). My Problem: data.live doesn't change from it's initial time it runs even when it has changed in the db. I know my mysql is working because it returs the right value on the initial load. It seems like a caching issue. Any help is greatly appreciated. function checkLive() { var live = <?=$result["live"]?>; $.ajax({ type: 'get', url: '/live/live.php', dataType: 'json', success: function(data) { console.log('checking for updates... current:' + data.live); if (data.live == live) { return; } else { var elems = $('div.player_meta, object, h3.offline_message'); if (data.live == '1') { elems.removeClass('offline').addClass('live'); } else { elems.addClass('live').addClass('offline'); } } } }); setTimeout(function() { checkLive() } ,15000); } checkLive();

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  • Problem in thread pool implementation(C#3.0)

    - by Newbie
    Hi Experts, I have done the below thread pool program but the problem is that the WaitCallBackMethod(here ThreadPoolCallback) is getting called 2 times(which ideally should be called 1ce). what is the misktake I am making? public class Calculation { #region Private variable declaration ManualResetEvent[] factorManualResetEvent = null; #endregion public void Compute() { factorManualResetEvent = new ManualResetEvent[2]; for (int i = 0; i < 2; i++){ factorManualResetEvent[i] = new ManualResetEvent(false); ThreadPool.QueueUserWorkItem(ThreadPoolCallback, i);} //Wait for all the threads to complete WaitHandle.WaitAll(factorManualResetEvent); //Proceed with the next task(s) NEXT_TASK_TO_BE_EXECUTED(); } #region Private Methods // Wrapper method for use with thread pool. public void ThreadPoolCallback(Object threadContext) { int threadIndex = (int)threadContext; Method1(); Method2(); factorManualResetEvent[threadIndex].Set(); } private void Method1 () { //Code of method 1} private void Method2 () { //Code of method 2 } #endregion } I am using C#3.0 Thanks

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  • C# Basic Multi-Threading Question: Call Method on Thread A from Thread B (Thread B started from Thre

    - by Nick
    What is the best way to accomplish this: The main thread (Thread A) creates two other threads (Thread B and Thread C). Threads B and C do heavy disk I/O and eventually need to pass in resources they created to Thread A to then call a method in an external DLL file which requires the thread that created it to be called correctly so only Thread A can call it. The only other time I ever used threads was in a Windows Forms application, and the invoke methods were just what I needed. This program does not use Windows Forms, and as such there are no Control.Invoke methods to use. I have noticed in my testing that if a variable is created in Thread A, I have no trouble accessing and modifying it from Thread B/C which seems very wrong to me. With Winforms, I was sure it threw errors for trying to access things created on other threads. I know it is unsafe to change things from multiple threads, but I really hoped .NET would forbid it altogether to ensure safe coding. Does .NET do this, and I am just missing the boat, or does it only do it with WinForm apps? Since it does seemingly allow this, do I do something like an OS would do, create a flag and monitor it from Thread A to see if it changes. If it does, then call the method. Doesnt the event handler essentially do this, so could an event be used somehow called on the main thread?

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  • Manipulating gl_LightSource[gl_MaxLights]

    - by pion
    The The OpenGL ® Shading Language Spec version 1.20 http://www.opengl.org/registry/doc/GLSLangSpec.Full.1.20.8.pdf shows the following: struct gl_LightSourceParameters { vec4 ambient; // Acli vec4 diffuse; // Dcli vec4 specular; // Scli vec4 position; // Ppli vec4 halfVector; // Derived: Hi vec3 spotDirection; // Sdli float spotExponent; // Srli float spotCutoff; // Crli // (range: [0.0,90.0], 180.0) float spotCosCutoff; // Derived: cos(Crli) // (range: [1.0,0.0],-1.0) float constantAttenuation; // K0 float linearAttenuation; // K1 float quadraticAttenuation;// K2 }; uniform gl_LightSourceParameters gl_LightSource[gl_MaxLights]; Also, http://www.lighthouse3d.com/opengl/glsl/index.php?ogldir1 shows the following code snippets: lightDir = normalize(vec3(gl_LightSource[0].position)); https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html#5.10 shows many uniform* functions but nothing seems to deal with an array of uniform variable like gl_LightSource[0]. How do we set the gl_LightSource[0] fields in WebGL using JavaScript? For example, gl_LightSource[0].position Thanks in advance for your help. Note: Cross post on http://www.khronos.org/message_boards/viewtopic.php?f=43&t=3373

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  • php validate integer [updated]

    - by George Garchagudashvili
    Read B A: I'll give quick example: $a = "\n \t 34 3"; // string(9) $aint = intval($a); // int(34) var_dump($a == $aint); result: bool(true) call me noob but can you tell me why/how does these variables do pass equalization test? What I want to achieve is to check if '1989' equals 1989 would be true, but not any other case. ex: '1989 ' should not pass the test. Also I don't want to use regex. B: I need to validate if variable is integer, I've tried all the available built-in functions or helpful tips, but the only best solution would be regex which I don't want to use this time. also filter_var is not best because it also filters data, but I want to only validate it. 123 -123 '123' '-123' these inputs to be only true, false otherwise I've tried many different options: ctype_digit("-123"); // false - doesn't work is_int('123'); // false filter_var(' 123 ', FILTER_VALIDATE_INT) !== false; // true - doesn't work

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  • Are Interfaces "Object"?

    - by PrashantGupta
    package inheritance; class A{ public String display(){ return "This is A!"; } } interface Workable{ public String work(); } class B extends A implements Workable{ public String work(){ return "B is working!"; } } public class TestInterfaceObject{ public static void main(String... args){ B obj=new B(); Workable w=obj; //System.out.println(w.work()); //invoking work method on Workable type reference System.out.println(w.display()); //invoking display method on Workable type reference //System.out.println(w.hashCode()); // invoking Object's hashCode method on Workable type reference } } As we know that methods which can be invoked depend upon the type of the reference variable on which we are going to invoke. Here, in the code, work() method was invoked on "w" reference (which is Workable type) so method invoking will compile successfully. Then, display() method is invoked on "w" which yields a compilation error which says display method was not found, quite obvious as Workable doesn't know about it. Then we try to invoke the Object class's method i.e. hashCode() which yields a successful compilation and execution. How is it possible? Any logical explanation?

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  • Insertion into BST without header Node JAVA

    - by Petiatil
    I am working on a recursive insertion method for a BST. This function is suppose to be a recursive helper method and is in a private class called Node. The Node class is in a class called BinarySearchTree which contains an instance variable for the root. When I am trying to insert an element, I get a NullPointerException at : this.left = insert(((Node)left).element); I am unsure about why this occurs. If I understand correctly, in a BST, I am suppose to insert the item at the last spot on the path transversed. Any help is appreciated! private class Node implements BinaryNode<E> { E item; BinaryNode<E> left, right; public BinaryNode<E> insert(E item) { int compare = item.compareTo(((Node)root).item); if(root == null) { root = new Node(); ((Node)root).item = item; } else if(compare < 0) { this.left = insert(((Node)left).item); } else if(compare > 0) { this.right = insert(((Node)right).item); } return root; } }

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  • List of values as keys for a Map

    - by thr
    I have lists of variable length where each item can be one of four unique, that I need to use as keys for another object in a map. Assume that each value can be either 0, 1, 2 or 3 (it's not integer in my real code, but a lot easier to explain this way) so a few examples of key lists could be: [1, 0, 2, 3] [3, 2, 1] [1, 0, 0, 1, 1, 3] [2, 3, 1, 1, 2] [1, 2] So, to re-iterate: each item in the list can be either 0, 1, 2 or 3 and there can be any number of items in a list. My first approach was to try to hash the contents of the array, using the built in GetHashCode() in .NET to combine the hash of each element. But since this would return an int I would have to deal with collisions manually (two equal int values are identical to a Dictionary). So my second approach was to use a quad tree, breaking down each item in the list into a Node that has four pointers (one for each possible value) to the next four possible values (with the root node representing [], an empty list), inserting [1, 0, 2] => Foo, [1, 3] => Bar and [1, 0] => Baz into this tree would look like this: Grey nodes nodes being unused pointers/nodes. Though I worry about the performance of this setup, but there will be no need to deal with hash collisions and the tree won't become to deep (there will mostly be lists with 2-6 items stored, rarely over 6). Is there some other magic way to store items with lists of values as keys that I have missed?

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  • Returning a dynamically created array from function

    - by informer2000
    I'm trying to create a function that would dynamically allocate an array, sets the values of the elements, and returns the size of the array. The array variable is a pointer that is declared outside the function and passed as a parameter. Here is the code: #include <cstdlib> #include <iostream> using namespace std; int doArray(int *arr) { int sz = 10; arr = (int*) malloc(sizeof(int) * sz); for (int i=0; i<sz; i++) { arr[i] = i * 5; } return sz; } int main(int argc, char *argv[]) { int *arr = NULL; int size = doArray(arr); for (int i=0; i<size; i++) { cout << arr[i] << endl; } return 0; } For some reason, the program terminates on the first iteration of the for loop in main()! Am I doing something wrong?

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  • Help optimizing a query with 16 subqueries

    - by Webnet
    I have indexes/primaries on all appropriate ID fields for each type. I'm wondering though how I could make this more efficient. It takes a while to load the page with only 15,000 rows and that'll quickly grow to 500k. The $whereSql variable simply has a few more parameters for the main ebay_archive_listing table. NOTE: This is all done in a single query because I have ASC/DESC sorting for each subquery value. NOTE: I've converted some of the sub queries to INNER JOIN's SELECT product_master.product_id, ( SELECT COUNT(listing_id) FROM ebay_archive_product_listing_assoc '.$listingCountJoin.' WHERE ebay_archive_product_listing_assoc.product_id = product_master.product_id) as listing_count, sku, type_id, ( SELECT AVG(ebay_archive_listing.current_price) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.current_price > 0 ) as average_bid_price, ( SELECT AVG(ebay_archive_listing.buy_it_now_price) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.buy_it_now_price > 0 ) as average_buyout_price, ( SELECT MIN(ebay_archive_listing.current_price) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.current_price > 0 ) as lowest_bid_price, ( SELECT MAX(ebay_archive_listing.current_price) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.current_price > 0 ) as highest_bid_price, ( SELECT MIN(ebay_archive_listing.buy_it_now_price) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.current_price > 0 ) as lowest_buyout_price, ( SELECT MAX(ebay_archive_listing.buy_it_now_price) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.current_price > 0 ) as highest_buyout_price, round((( SELECT COUNT(ebay_archive_listing.id) FROM ebay_archive_listing INNER JOIN ebay_archive_product_listing_assoc ON ( ebay_archive_product_listing_assoc.listing_id = ebay_archive_listing.id AND ebay_archive_product_listing_assoc.product_id = product_master.product_id ) WHERE '.$whereSql.' AND ebay_archive_listing.status_id = 2 ) / ( SELECT COUNT(listing_id) FROM ebay_archive_product_listing_assoc '.$listingCountJoin.' WHERE ebay_archive_product_listing_assoc.product_id = product_master.product_id ) * 100), 1) as sold_percent FROM product_master '.$joinSql.' WHERE product_master.product_id IN ( SELECT product_id FROM ebay_archive_product_listing_assoc INNER JOIN ebay_archive_listing ON ( ebay_archive_listing.id = ebay_archive_product_listing_assoc.listing_id AND '.$whereSql.' ) )

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