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  • Python-based password tracker (or dictionary)

    - by Arrieta
    Hello: Where we work we need to remember about 10 long passwords which need to change every so often. I would like to create a utility which can potentially save these passwords in an encrypted file so that we can keep track of them. I can think of some sort of dictionary passwd = {'host1':'pass1', 'host2':'pass2'}, etc, but I don't know what to do about encryption (absolutely zero experience in the topic). So, my question is really two questions: Is there a Linux-based utility which lets you do that? If you were to program it in Python, how would you go about it? A perk of approach two, would be for the software to update the ssh public keys after the password has been changed (you know the pain of updating ~15 tokens once you change your password). As it can be expected, I have zero control over the actual network configuration and the management of scp keys. I can only hope to provide a simple utility to me an my very few coworkers so that, if we need to, we can retrieve a password on demand. Cheers.

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  • Chicken and egg problem (restore database) when trying to write unit test against SQl Server 2008.

    - by Hamish Grubijan
    Ok, they are not unit tests but end-to-end tests. The setup is somewhat involved. Unit tests will use C#, ODBC connection. Every unit tests will try to clean up after itself, but every 20 tests or so (once per C# class) we would need to do a full database restore. I do not think I can do it over an ODBC connection, according to this document: http://www.sql-server-performance.com/articles/dba/Obtain_Exclusive_Access_to_Restore_SQL_Server_p1.aspx Msg 6104, Level 16, State 1, Line 1 Cannot use KILL to kill your own process. However, I would like to, so that 199 tests do not go amok because of a bad clean-up. Is there another way? Perhaps I can open a different "connection" such as use COM automation or something of that sort, and then kill all database connections from there? If so, how can I do that? Also, will the clients be able to re-connect automatically after a restore, or would I have to dismantle everything once every 20 tests or so? If you find this question confusing, please let me know what your questions are. Thanks!

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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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  • Visual Studio internal project references not always working

    - by Chris
    I am using Visual Studio and a solution with 10 or so projects in (mostly VB, some C#) which have various dependencies set up. Usually when I compile the solution it works fine. Occasionally when I do it I get a build error saying that one of the projects referenced is the wrong version (I think always the same one, possibly may be two that can cause problems). In this case going to the solution explorer and right clicking on the mentioned project and saying "rebuild" followed by another full build makes it work fine. I assume there is something set up wrong somewhere but I didn't set up the solution myself initially and a quick look through doesn't show anything immediately wrong. It feels like there is some kind of race condition, that VS is internally setting the version number of the project it needs before that project has been rebuilt and thus gets it wrong or something like that but I'm sure VS should handle all this sort of thing properly. Can anybody please suggest places that I could check for whether this has been correctly set up... And I should finally note that since I don't have reliable repro of this I may not be able to respond to questions too quickly. For example the obvious one of "Could you give the exact error message" will have to wait since I didn't think to copy it this morning, it was only after I cleared it up with the above steps that I thought to post here. Similarly any solutions may take a while to confirm.

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  • An array problem in C++

    - by manugupt1
    To access the array indice at the xth position we can use some sort of illustration as shown below #include<iostream> using namespace std; int main(){ float i[20]; for(int j=0;j<=20;j++) i[j]=0; } However the following piece of code does not work #include<iostream> using namespace std; float oldrand[55]; int jrand; void advance_random(){ int j1; float new_random; for(j1=0;j1<=23;j1++){ int temp = j1+30; new_random = (oldrand[j1]) - (oldrand[temp]); if(new_random <0.0) new_random = new_random+1; oldrand[j1] = new_random; } for(j1=24;j1<=54;j1++){ new_random[j1] = oldrand[j1] - oldrand[j1-23]; if(new_random[j1]<0.0) new_random[j1] = new_random + 1; oldrand[j1]=new_random; } } I recieve the following error ga.cpp:20: error: invalid types ‘float[int]’ for array subscript ga.cpp:21: error: invalid types ‘float[int]’ for array subscript ga.cpp:22: error: invalid types ‘float[int]’ for array subscript I am not able to find a mistake in my code please help me

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  • UDP security and identifying incoming data.

    - by Charles
    I have been creating an application using UDP for transmitting and receiving information. The problem I am running into is security. Right now I am using the IP/socketid in determining what data belongs to whom. However, I have been reading about how people could simply spoof their IP, then just send data as a specific IP. So this seems to be the wrong way to do it (insecure). So how else am I suppose to identify what data belongs to what users? For instance you have 10 users connected, all have specific data. The server would need to match the user data to this data we received. The only way I can see to do this is to use some sort of client/server key system and encrypt the data. I am curious as to how other applications (or games, since that's what this application is) make sure their data is genuine. Also there is the fact that encryption takes much longer to process than unencrypted. Although I am not sure by how much it will affect performance. Any information would be appreciated. Thanks.

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  • Find messages from certain key till certain key while being able to remove stale keys.

    - by Alfred
    My problem Let's say I add messages to some sort of datastructure: 1. "dude" 2. "where" 3. "is" 4. "my" 5. "car" Asking for messages from index[4,5] should return: "my","car". Next let's assume that after a while I would like to purge old messages because they aren't useful anymore and I want to save memory. Let's say at time x messages[1-3] became stale. I assume that it would be most efficient to just do the deletion once every x seconds. Next my datastructure should contain: 4. "my" 5. "car" My solution? I was thinking of using a concurrentskiplistset or concurrentskiplist map. Also I was thinking of deleting the old messages from inside a newSingleThreadScheduledExecutor. I would like to know how you would implement(efficiently/thread-safe) this or maybe use a library?

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  • How do I use the Enum value from a class in another part of code?

    - by ChiggenWingz
    Coming from a C# background from a night course at a local college, I've sort of started my way in C++. Having a lot pain getting use to the syntax. I'm also still very green when it comes to coding techniques. From my WinMain function, I want to be able to access a variable which is using an enum I declared in another class. (inside core.h) class Core { public: enum GAME_MODE { INIT, MENUS, GAMEPLAY }; GAME_MODE gameMode; Core(); ~Core(); ...OtherFunctions(); }; (inside main.cpp) Core core; int WINAPI WinMain(...) { ... startup code here... core.gameMode = Core.GAME_MODE.INIT; ...etc... } Basically I want to set that gameMode to the enum value of Init or something like that from my WinMain function. I want to also be able to read it from other areas. I get the error... expected primary-expression before '.' token If I try to use core.gameMode = Core::GAME_MODE.INIT;, then I get the same error. I'm not fussed about best practices, as I'm just trying to get the basic understanding of passing around variables in C++ between files. I'll be making sure variables are protected and neatly tucked away later on once I am use to the flexibility of the syntax. If I remember correctly, C# allowed me to use Enums from other classes, and all I had to do was something like Core.ENUMNAME.ENUMVALUE. I hope what I'm wanting to do is clear :\ As I have no idea what a lot of the correct terminology is.

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  • PHP hashing function not working properly

    - by Jordan Foreman
    So I read a quick PHP login system securing article, and was trying to sort of duplicate their hashing method, and during testing, am not getting the proper output. Here is my code: function decryptPassword($pw, $salt){ $hash = hash('sha256', $salt . hash('sha256', $pw)); return $hash; } function encryptPassword($pw){ $hash = hash('sha256', $pw); $salt = substr(md5(uniqid(rand(), true)), 0, 3); $hash = hash('sha265', $salt . $hash); return array( 'salt' => $salt, 'hash' => $hash ); } And here is my testing code: $pw = $_GET['pw']; $enc = encryptPassword($pw); $hash = $enc['hash']; $salt = $enc['salt']; echo 'Pass: ' . $pw . '<br />'; echo 'Hash: ' . $hash . '<br />'; echo 'Salt: ' . $salt . '<br />'; echo 'Decrypt: ' . decryptPassword($hash, $salt); Now, the output of this should be pretty obvious, but unfortunately, the $hash variable always comes out empty! I'm trying to figure out what the problem could be, and my only guess would be the second $hash assignment line in the encryptPassword(..) function. After a little testing, I've determined that the first assignment works smoothly, but the second does not. Any suggestions? Thanks SO!

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  • How can I get my business objects layer to use the management layer in their methods?

    - by Tom Pickles
    I have a solution in VS2010 with several projects, each making up a layer within my application. I have business entities which are currently objects with no methods, and I have a management layer which references the business entities layer in it's project. I now think I have designed my application poorly and would like to move methods from helper classes (which are in another layer) into methods I'll create within the business entities themselves. For example I have a VirtualMachine object, which uses a helper class to call a Reboot() method on it which passes the request to the management layer. The static manager class talks to an API that reboots the VM. I want to move the Reboot() method into the VirtualMachine object, but I will need to reference the management layer: public void Reboot() { VMManager.Reboot(this.Name); } So if I add a reference to my management project in my entities project, I get the circular dependency error, which is how it should be. How can I sort this situation out? Do I need to an yet another layer between the entity layer and the management layer? Or, should I just forget it and leave it as it is. The application works ok now, but I am concerned my design isn't particularly OOP centric and I would like to correct this.

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  • Error when running a basic Hadoop code

    - by Abhishek Shivkumar
    I am running a hadoop code that has a partitioner class inside the job. But, when I run the command hadoop jar Sort.jar SecondarySort inputdir outputdir I am getting a runtime error that says class KeyPartitioner not org.apache.hadoop.mapred.Partitioner. I have ensured that the KeyPartitioner class has extended the Partitioner class, but why am I getting this error? Here is the driver code: JobConf conf = new JobConf(getConf(), SecondarySort.class); conf.setJobName(SecondarySort.class.getName()); conf.setJarByClass(SecondarySort.class); conf.setInputFormat(TextInputFormat.class); conf.setOutputFormat(TextOutputFormat.class); conf.setMapOutputKeyClass(StockKey.class); conf.setMapOutputValueClass(Text.class); conf.setPartitionerClass((Class<? extends Partitioner<StockKey, DoubleWritable>>) KeyPartitioner.class); conf.setMapperClass((Class<? extends Mapper<LongWritable, Text, StockKey, DoubleWritable>>) StockMapper.class); conf.setReducerClass((Class<? extends Reducer<StockKey, DoubleWritable, Text, Text>>) StockReducer.class); and here is the code of the partitioner class: public class KeyPartitioner extends Partitioner<StockKey, Text> { @Override public int getPartition(StockKey arg0, Text arg1, int arg2) { int partition = arg0.name.hashCode() % arg2; return partition; } }

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  • Android: Adding header to dynamic listView

    - by cg5572
    I'm still pretty new to android coding, and trying to figure things out. I'm creating a listview dynamically as shown below (and then disabling items dynamically also) - you'll notice that there's no xml file for the activity itself, just for the listitem. What I'd like to do is add a static header to the page. Could someone explain to me how I can modify the code below to EITHER add this programatically within the java file, before the listView, OR edit the code below so that it targets a listView within an xml file! Help would be much appreciated!!! public class Start extends ListActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); DataBaseHelper myDbHelper = new DataBaseHelper(null); myDbHelper = new DataBaseHelper(this); try { myDbHelper.openDataBase(); }catch(SQLException sqle){ throw sqle; } ArrayList<String> categoryList = new ArrayList<String>(); Cursor cur = myDbHelper.getAllCategories(); cur.moveToFirst(); while (cur.isAfterLast() == false) { if (!categoryList.contains(cur.getString(1))) { categoryList.add(cur.getString(1)); } cur.moveToNext(); } cur.close(); Collections.sort(categoryList); setListAdapter(new ArrayAdapter<String>(this, R.layout.listitem, categoryList) { @Override public View getView(int position, View convertView, ViewGroup parent) { View view = super.getView(position, convertView, parent); if(Arrays.asList(checkArray3).contains(String.valueOf(position))){ view.setEnabled(false); } else { view.setEnabled(true); } return view; } }); } @Override protected void onListItemClick(ListView l, View v, int position, long id) { if(v.isEnabled()) { String clickedCat = l.getItemAtPosition(position).toString(); Toast.makeText(this, clickedCat, Toast.LENGTH_SHORT).show(); finish(); Intent myIntent = new Intent(getApplicationContext(), Questions.class); myIntent.putExtra("passedCategory", clickedCat); myIntent.putExtra("startTrigger", "go"); startActivity(myIntent); } } }

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  • Are there really safe and legal resources for sound effects to use in applications?

    - by mystify
    For those who want to opt for "close" immediately: Great user interfaces need great sound effects, right? User interfaces are programmed by programmers, right? So this is a programming question, ok? I had a very hard time to find good and legal sound resources. I am not looking for free sounds. Proper licensing is absolutely crucial, and I don't want to get sued by multibilliondollar music companies, hollywood sound studios and their highly overpaid lawyers. They cry about people downloading their stuff in file sharing sites but when someone comes and wants to really license stuff, the market is so empty like an open and unwatched gold mine. Trust me, whatever I type into google, I always end up getting sort of opaque and strange music libraries that do charge money, but refuse to provide proper licensing evidence to the licensee. When you pay money and they only count how many files you downloaded, that can never be a valid license, nor any evidence for you that you did license the sounds. Imagine that contributor suing you and you say: "I licensed it at xy", and his lawyer just smiles: "Show me proof, mofo!". So you loose a million dollars, or 1 for every downloaded app. Congrats. But that's the way all those "hey we're the worlds largest sound effect library" libraries are doing it. It's really annoying. And I hope someone here is able to point out a sound effects ressource which is A) big B) used by professinals C) has a reasonable pricing and licensing model D) provides the licensee with proper legal evidence about licensed sounds You know, I'm not from the US and typically you US folks are the ones who invent the cool stuff on the net, and maybe I just missed a new great start up. So?

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  • Most efficient way to LIMIT results in a JOIN?

    - by johnnietheblack
    I have a fairly simple one-to-many type join in a MySQL query. In this case, I'd like to LIMIT my results by the left table. For example, let's say I have an accounts table and a comments table, and I'd like to pull 100 rows from accounts and all the associated comments rows for each. Thy only way I can think to do this is with a sub-select in in the FROM clause instead of simply selecting FROM accounts. Here is my current idea: SELECT a.*, c.* FROM (SELECT * FROM accounts LIMIT 100) a LEFT JOIN `comments` c on c.account_id = a.id ORDER BY a.id However, whenever I need to do a sub-select of some sort, my intermediate level SQL knowledge feels like it's doing something wrong. Is there a more efficient, or faster, way to do this, or is this pretty good? By the way... This might be the absolute simplest way to do this, which I'm okay with as an answer. I'm simply trying to figure out if there IS another way to do this that could potentially compete with the above statement in terms of speed.

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  • Index question: Select * with WHERE clause. Where and how to create index

    - by Mestika
    Hi, I’m working on optimizing some of my queries and I have a query that states: select * from SC where c_id ="+c_id” The schema of ** SC** looks like this: SC ( c_id int not null, date_start date not null, date_stop date not null, r_t_id int not null, nt int, t_p decimal, PRIMARY KEY (c_id, r_t_id, date_start, date_stop)); My immediate bid on how the index should be created is a covering index in this order: INDEX(c_id, date_start, date_stop, nt, r_t_id, t_p) The reason for this order I base on: The WHERE clause selects from c_id thus making it the first sorting order. Next, the date_start and date_stop to specify a sort of “range” to be defined in these parameters Next, nt because it will select the nt Next the r_t_id because it is a ID for a specific type of my r_t table And last the t_p because it is just a information. I don’t know if it is at all necessary to order it in a specific way when it is a SELECT ALL statement. I should say, that the SC is not the biggest table. I can say how many rows it contains but a estimate could be between <10 and 1000. The next thing to add is, that the SC, in different queries, inserts the data into the SC, and I know that indexes on tables which have insertions can be cost ineffective, but can I somehow create a golden middle way to effective this performance. Don't know if it makes a different but I'm using IBM DB2 version 9.7 database Sincerely Mestika

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  • What are the javascript performance tradeoffs in adding id's to dom elements?

    - by Blinky
    For example, I have a website which has a dynamically-generated segment of its dom which looks roughly like this: <div id="master"> <div class="child"> ... </div> <div class="child"> ... </div> <div class="child"> ... </div> ... <div class="child"> ... </div> </div> There might be hundreds of child elements in this manner, and they, too, might have yet more children. At present, none of them have id's except for the master. Javascript manipulates them via dom-walking. It's a little scary. I'd like to add id's, e.g.: <div id="master"> <div id="child1" class="child"> ... </div> <div id="child2" class="child"> ... </div> <div id="child3" class="child"> ... </div> ... <div id="childN" class="child"> ... </div> </div> What are the tradeoffs in adding id's to these divs? Certainly, jQuery must maintain a hash of id's, so there's going to be some sort of performance hit. Any general guidelines in when adding additional id's is a bad idea? Is jQuery so awesome that, in practice, it doesn't matter?

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  • Run multiple MySQL queries based on a series of ifs

    - by OldWest
    I am just getting started on this complex query I need to write and was hoping for any suggestions or feedback regarding table structure and the actual query itself.. I've already created my tables and populated test data, and now just trying to sort out how and what is possible within MySQL. Here is an outline of the problem: End result: Listing of rates based on specific queried criteria (see below): Age: [ 27 ] Spouse Age: [ 25 ] Num of Children: [ 3 ] Zip Code: [ 97128 ] The problem I am running into is each company that provides rates has a unique way of dealing with the rate. And I am looking for the best approach for multiple queries based on the company (one query with results for each company more or less all combined into one result set). Here are some facts: - Each company deals with zip code ranges which assist in the query result. - Each company has a different method of calculating the rate based on the Applicant, Spouse, Num of Children: Example, a) Company A determines rate by: Applicant + Spouse + Child(ren) = rate (age is pertinent to the applicant within a range). b) Company B determines the rate by total number of applicants like: 1, 2, 3, 4, 5, 6+ = rate (and age is ignored). First off, what would I call this type of query? Multiple nested query? And should I intertwine php within it to determine the If()s ... I apologize if this thread lacks sufficient data, so please tell me anything you would like to see.

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  • Django templatetag "order of processing"

    - by Jason Persampieri
    I am trying to write a set of template tags that allow you to easily specify js and css files from within the template files themselves. Something along the lines of {% requires global.css %}, and later in the request, {% get_required_css %}. I have this mostly working, but there are a couple of issues. We'll start with the 'timing' issues. Each template tag is made up of two steps, call/init and render. Every call/init happens before any render procedure is called. In order to guarantee that all of the files are queued before the {% get_required_css %} is rendered, I need to build my list of required files in the call/init procedures themselves. So, I need to collect all of the files into one bundle per request. The context dict is obviously the place for this, but unfortunately, the call/init doesn't have access to the context variable. Is this making sense? Anyone see a way around this (without resorting to a hack-y global request object)? Another possibility to store these in a local dict but they would still need to be tied to the request somehow... possibly some sort of {% start_requires %} tag? But I have no clue how to make that work either.

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  • Actionscript - combining AS2 assets into a single SWF

    - by Justin Bachorik
    Hi guys, I have a flash project that I'm trying to export as a single SWF. There's a main SWF file that loads about 6 other SWFs, and both the main and the child SWFs reference other external assets (images, sounds, etc). I'd like to package everything as a single .swf file so I don't have to tote the other assets around with the .swf. All the coding is done in the timeline, but the assets haven't been imported into the Flash Authoring environment and I don't have time to do that right now (there are too many references to them everywhere). I'm hoping that there's just an option I'm missing that allows this sort of packaged export, but I haven't found anything like that. I don't have access to Flex or mxmlc (and as the AS is timeline-based, they wouldn't necessarily help me). Any thoughts? Thanks! PS...if there's no way of doing exactly what I'm saying, I could deal with having all the assets in a "assets" folder or something like that, so I'd just be toting around main.swf and an assets folder. The problem here is that all the references to the assets assume that they're in the same folder as the main.swf file, so everything's assumed to be local...is there a way to change the scope of all external references in Flash (so, for example, all local references in the code are actually searched in /assets)?

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  • Practicing inserting data into an array by using binary search, few problems

    - by HelpNeeder
    I'm trying to create a method which inserts and then sort elements in form of binary form. The problem I am experiencing that my code doesn't insert data correctly which means that output does not appear to be in order at all. The list is not organized, and data is added in order that is being inserted. Now, 2 questions, what am I doing wrong here? And how to fix this? public void insertBinarySearch(long value) // put element into array { int j = 0; int lower = 0; int upper = elems-1; int cur = 0; while (cur < elems) { curIn = (lower + upper ) / 2; if(a[cur] < value) { j = cur + 1; break; } else if(a[cur] > value) { j = cur; break; } else { if(a[cur] < value) lower = cur + 1; else upper = cur - 1; } } for(int k = elems; k > j; k--) a[k] = a[k-1]; a[j] = value; elems++; }

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  • Attempted GCF app for Android

    - by Aaron
    I am new to Android and am trying to create a very basic app that calculates and displays the GCF of two numbers entered by the user. Here is a copy of my GCF.java: package com.example.GCF; import java.util.Arrays; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class GCF extends Activity { private TextView mAnswer; private EditText mA, mB; private Button ok; private String A, B; private int iA, iB; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mA = (EditText) findViewById(R.id.entry); mB = (EditText) findViewById(R.id.entry1); ok = (Button) findViewById(R.id.ok); mAnswer = (TextView) findViewById(R.id.answer1); ok.setOnClickListener(new OnClickListener() { public void onClick(View v) { A = mA.getText().toString(); B = mB.getText().toString(); } }); // the String to int conversion happens here iA = Integer.parseInt(A.trim()); iB = Integer.parseInt(B.trim()); while (iA != iB) { int[] nums={ iA, iB, Math.abs(iA-iB) }; Arrays.sort(nums); iA=nums[0]; iB=nums[1]; } updateDisplay(); } private void updateDisplay() { mAnswer.setText( new StringBuilder().append(iA)); } } Any Suggestions? Thank you!

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  • Prevent duplicate entries in arraylist

    - by timyh
    Say I create some object class like so public class thing { private String name; private Integer num; public oDetails (String a, Integer b) { name = a; num = b; } ...gets/ sets/ etc Now I want to create an arraylist to hold a number of this object class like so. ArrayList<thing> myList = new ArrayList<thing>; thing first = new thing("Star Wars", 3); thing second = new thing("Star Wars", 1); myList.add(first); myList.add(second); I would like to include some sort of logic so that in this case...when we try and add object "second" rather than add a new object to the arrayList, we add second.getNum() to first.getNum(). So if you were to iterate through the ArrayList it would be "Star Wars", 4 I am having trouble coming up with an elegant way of handling this. And as the arraylist grows, searching through it to determine if there are duplicate name items becomes cumbersome. Can anyone provide some guidance on this?

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  • Large Switch statements: Bad OOP?

    - by Mystere Man
    I've always been of the opinion that large switch statements are a symptom of bad OOP design. In the past, I've read articles that discuss this topic and they have provided altnerative OOP based approaches, typically based on polymorphism to instantiate the right object to handle the case. I'm now in a situation that has a monsterous switch statement based on a stream of data from a TCP socket in which the protocol consists of basically newline terminated command, followed by lines of data, followed by an end marker. The command can be one of 100 different commands, so I'd like to find a way to reduce this monster switch statement to something more manageable. I've done some googling to find the solutions I recall, but sadly, Google has become a wasteland of irrelevant results for many kinds of queries these days. Are there any patterns for this sort of problem? Any suggestions on possible implementations? One thought I had was to use a dictionary lookup, matching the command text to the object type to instantiate. This has the nice advantage of merely creating a new object and inserting a new command/type in the table for any new commands. However, this also has the problem of type explosion. I now need 100 new classes, plus I have to find a way to interface them cleanly to the data model. Is the "one true switch statement" really the way to go? I'd appreciate your thoughts, opinions, or comments.

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  • How to implement a grapher in C#

    - by iansinke
    So I'm writing a graphing calculator. So far I have a semi-functional grapher, however, I'm having a hard time getting a good balance between accurate graphs and smooth looking curves. The current implementation (semi-pseudo-code) looks something like this: for (float i = GraphXMin; i <= GraphXMax; i++) { PointF P = new PointF(i, EvaluateFunction(Function, i) ListOfPoints.Add(P) } Graphics.DrawCurve(ListOfPoints) The problem with this is since it only adds a point at every integer value, graphs end up distorted when their turning points don't fall on integers (e.g. sin(x)^2). I tried incrementing i by something smaller (like 0.1), which works, but the graph looks very rough. I am using C# and GDI+. I have SmoothingMethod set to AntiAlias, so that's not the problem, as you can see from the first graph. Is there some sort of issue with drawing curves with a lot of points? Should the points perhaps be positioned exactly on pixels? I'm sure some of you have worked on something very similar before, so any suggestions? While you're at it, do you have any suggestions for graphing functions with asymptotes? e.g. 1/x^2 P.S. I'm not looking for a library that does all this - I want to write it myself.

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  • How to create a desktop shortcut to a website with website logo as icon?

    - by Wbdvlpr
    Hi I need a solution which allows users to create a desktop shortcut to a website, preferably with website logo as shortcut icon. There are ways users can create shortcut such as drag drop favicon or right click create new shortcut etc. This works but also creates the shortcut with default IE icon on windows. I am trying to avoid this method for this icon and some other reasons. I thought of creating a website-title.URL file, and tell users to download and save file to their desktop, again this works but doesn't solve the icon problem as the website logo (.ico) has to be at local disk and at a pre-specified location [IconFile=path]. I was wondering if it is possible to create a some sort of installer or windows application which users can download from the website. Once its executed by user, it creates this .URL file on user desktop which have IconFile path pre-specified, and copy the website-logo.ico at path specified in .URL file etc. So my questions are - Is it possible to create such a solution? What programming languages can be used to achieve this? Can this installer/app be made to work on non-windows machines as well? From developments point of view how big project it is? if I have to hire a programmer to do this. Please let me know if you need more information. Thanks

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