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• Vector deltas and moving in unknown areas

  - by dekz

  Hi All, I was in need of a little math help that I can't seem to find the answer to, any links to documentation would be greatly appreciated. Heres my situation, I have no idea where I am in this maze, but I need to move around and find my way back to the start. I was thinking of implementing a waypoint list of places i've been offset from my start at 0,0. This is a 2D cartesian plane. I've been given 2 properties, my translation speed from 0-1 and my rotation speed from -1 to 1. -1 is very left and +1 is very right. These are speed and not angles so thats where my problem lies. If I'm given 0 as a translation speed and 0.2 I will continually turn to my right at a slow speed. How do I figure out the offsets given these 2 variables? I can store it every time I take a 'step'. I just need to figure out the offsets in x and y terms given the translations and rotation speeds. And the rotation to get to those points. Any help is appreciated.

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• What techniques can I employ to create a series of UI Elements from a collection of objects using WP

  - by elggarc

  I'm new to WPF and before I dive in solving a problem in completely the wrong way I was wondering if WPF is clever enough to handle something for me. Imagine I have a collection containing objects. Each object is of the same known type and has two parameters. Name (a string) and Picked (a boolean). The collection will be populated at run time. I would like to build up a UI element at run time that will represent this collection as a series of checkboxes. I want the Picked parameter of any given object in the collection updated if the user changes the selected state of the checkbox. To me, the answer is simple. I iterate accross the collection and create a new checkbox for each object, dynamically wiring up a ValueChanged event to capture when Picked should be changed. It has occured to me, however, that I may be able to harness some unknown feature of WPF to do this better (or "properly"). For example, could data binding be employed here? I would be very interested in anyone's thoughts. Thanks, E FootNote: The structure of the collection can be changed completely to better fit any chosen solution but ultimately I will always start from, and end with, some list of string and boolean pairs.

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• Return a Const Char* by reading an @property NSString in separate class

  - by Andrew

  I'm probably being an idiot here, but I cannot for the life of me find the answer that I'm looking for. I have an array of CalEvents returned from a CalendarStore query, and for other reasons I am finding the first location of any upcoming event for today that is not an all-day or multi-day event. +(const char*) suggestFirstiCalLocation{ CalCalendarStore *store = [CalCalendarStore defaultCalendarStore]; NSPredicate *allEventsPredicate = [CalCalendarStore eventPredicateWithStartDate:[NSDate date] endDate:[[NSDate date] initWithTimeIntervalSinceNow:3600] calendars:[store calendars]]; NSArray *currentEventCalendarArray = [store eventsWithPredicate:allEventsPredicate]; for (int i = 0; i< [currentEventCalendarArray count]; i++){ if (![[currentEventCalendarArray objectAtIndex:i] isAllDay]){ //Now that other events are cleared, check for multi-day NSDate *startOnDate = [[currentEventCalendarArray objectAtIndex:i] startDate]; NSDate *endOnDate = [[currentEventCalendarArray objectAtIndex:i] endDate]; if ([endOnDate timeIntervalSinceDate:startOnDate ] < 86400.0){ NSString * iCalLocation = [[currentEventCalendarArray objectAtIndex:i] location]; return [iCalLocation UTF8String]; } } } return ""; } For other reasons, I am returning a const char with the value of the location that is found. However, I cannot seem to return "iCalLocation" at all. The compiler fails on the line where I am initializing the "iCalLocation" variable: "Cannot convert to pointer type" Being frank: I am new to Objective-C, and I am still trying to figure points, properties, and such out.

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• steam condenser java errors

  - by w0rm

  I've been working on a little project involving Steam Condenser, a Steam API written in Java, but I haven't been able to actually do anything with it. I'll explain. This is what the wiki tells me: SteamId id = new SteamId("demomenz"); GameStats stats = id.getGameStats("tf2"); List achievements = stats.getAchievements(); The problem is, eclipse doesn't like it apparently, as it spits out this error: The constructor SteamId(String) is undefined and it gives me the option to change it to: SteamId id = new SteamId("demomenz", false); But at this point a different error comes out: The constructor SteamId(Object, boolean) is not visible So, I'm assuming this function is internal to the API, and should not be called from the outside. If anyone is familiar with this, or has a clue on why I'm getting this error (I'm fairly new to Java development), an answer would be greatly appreciated. UPDATE: The constructor SteamId(String) is undefined This is if I use SteamId.create(ConvertedID); (ConvertedID is a String containing the Steam64 ID). At this point I believe this API is not that well written, at least for java. Any other idea?

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• C#: An object reference is required for the non-static field, method, or Property

  - by Omin

  I feel bad for asking this when there are so many questions that are related but I was not able to find/understand the answer I am looking for. // 2. Develop a program to convert currency X to currency Y and visa versa. using System; class Problem2 { static void Main (string[] args) { while (true) { Console.WriteLine ("1. Currency Conversion from CAD to Won"); Console.WriteLine ("2. Currency Conversion from Won to Cad"); Console.Write ("Choose from the Following: (1 or 2)? "); int option = int.Parse( Console.ReadLine() ); //double x; if (option == 1) { Console.WriteLine ("Type in the amount you would like to Convert CAD to Won: "); //double y =double.Parse( Console.ReadLine()); //Console.WriteLine( cadToWon( y ) ); Console.WriteLine( cadToWon( double.Parse( Console.ReadLine() ) )); } if (option == 2) { Console.WriteLine ("Type in the amount you would like to Convert Won to CAD: "); Console.WriteLine( wonToCad (double.Parse( Console.ReadLine()))); } } } double cadToWon( double x ) { return x * 1113.26; } double wonToCad( double x) { return x / 1113.26; } } This give me the Error messgae "An object reference is required for the non-static field, method, or property 'Problem2..." I know that I'll be able to run the program if I add static infront of the methods but I'm wondering why I need it (I think it's because Main is static?) and what do I need to change in order to use these methods without adding static to them? Thank you

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• How to create custom MouseEvent.CLICK event in AS3 (pass parameters to function)?

  - by fromvega

  Hello, This question doesn't relate only to MouseEvent.CLICK event type but to all event types that already exist in AS3. I read a lot about custom events but until now I couldn't figure it out how to do what I want to do. I'm going to try to explain, I hope you understand: Here is a illustration of my situation: for(var i:Number; i < 10; i++){ var someVar = i; myClips[i].addEventListener(MouseEvent.CLICK, doSomething); } function doSomething(e:MouseEvent){ /* */ } But I want to be able to pass someVar as a parameter to doSomething. So I tried this: for(var i:Number; i < 10; i++){ var someVar = i; myClips[i].addEventListener(MouseEvent.CLICK, function(){ doSomething(someVar); }); } function doSomething(index){ trace(index); } This kind of works but not as I expect. Due to the function closures, when the MouseEvent.CLICK events are actually fired the for loop is already over and someVar is holding the last value, the number 9 in the example. So every click in each movie clip will call doSomething passing 9 as the parameter. And it's not what I want. I thought that creating a custom event should work, but then I couldn't find a way to fire a custom event when the MouseEvent.CLICK event is fired and pass the parameter to it. Now I don't know if it is the right answer. What should I do and how?

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

  - by Skylark

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

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• How to animate a path like it's being drawn, dot by dot? (Raphael.js)

  - by Anton

  How to animate a vector path like it's being drawn by hand? In other words, slowly show the path pixel by pixel. I'm using Raphaël.js, but if your answer is not library specific—like maybe there's some general programming pattern for doing that kind of thing (I'm fairly new to vector animation)—it's welcome! Update I know it's easy to do with straight paths, as easy as an example on that page:: path("M114 253").animate({path: "M114 253 L 234 253"}); But try to change code on that page, say, this way:: path("M114 26").animate({path: "M114 26 C 24 23 234 253 234 253"}); And you'll see what I mean. Path is certainly animated from it initial state (point "M114 26") to the end state (curve "C 24 23 234 253 234 253" starting on point "M114 26"), but not in a way specified in question, not like it's being drawn. (Sorry for not making clear from the start that I don't mean animating straight lines.) I don't see how animateAlong can do that either. It can animate an object along a path, and how can I make this path to gradually show itself while object is being animated along it?

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• PHP sleep() excution sequence while echoeing.

  - by Babiker

  I have the following: echo time()."<br>"; sleep(1); echo time()."<br>"; sleep(1); echo time()."<br>"; I wrote the preceding code with intention to echo time()."<br>" ln 1,echo time()."<br>" ln 4, wait a final second and then echo the final time()."<br>". Altough the time bieng echoed is correct when it comes to the intervals between time(), all echo functions are echoeing after the total of the waiting period/parameters in each sleep function. This is how the script runs: Excutes. Waits 2 secons. echoes 1275540664 1275540665 1275540666 Notice the correct incrementation in time() being echoed. My question is why is it not behaving like expected to where it echoes, waits a second, echoes again, waits one final second and then echos the last parameter? I know my question is a little confusing due to my wording, but i will try my hardest to answer any comments regarding this, thanks.

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• Project Euler #119 Make Faster

  - by gangqinlaohu

  Trying to solve Project Euler problem 119: The number 512 is interesting because it is equal to the sum of its digits raised to some power: 5 + 1 + 2 = 8, and 8^3 = 512. Another example of a number with this property is 614656 = 28^4. We shall define an to be the nth term of this sequence and insist that a number must contain at least two digits to have a sum. You are given that a2 = 512 and a10 = 614656. Find a30. Question: Is there a more efficient way to find the answer than just checking every number until a30 is found? My Code int currentNum = 0; long value = 0; for (long a = 11; currentNum != 30; a++){ //maybe a++ is inefficient int test = Util.sumDigits(a); if (isPower(a, test)) { currentNum++; value = a; System.out.println(value + ":" + currentNum); } } System.out.println(value); isPower checks if a is a power of test. Util.sumDigits: public static int sumDigits(long n){ int sum = 0; String s = "" + n; while (!s.equals("")){ sum += Integer.parseInt("" + s.charAt(0)); s = s.substring(1); } return sum; } program has been running for about 30 minutes (might be overflow on the long). Output (so far): 81:1 512:2 2401:3 4913:4 5832:5 17576:6 19683:7 234256:8 390625:9 614656:10 1679616:11 17210368:12 34012224:13 52521875:14 60466176:15 205962976:16 612220032:17

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• Passing user_id, site_id, and question_id to same table on create...

  - by bgadoci

  I can't seem to figure out how to do this. I am trying to pass four different variables to a single table. To be more specific I am trying to create a "like" in a likes table that also captures the site_id (like an answer), user_id, and the question_id. Here is the set up. class Like < ActiveRecord::Base belongs_to :site belongs_to :user belongs_to :question end I will spare you the reverse, has_many associations but they are there. Here is the likes controller where I think the problem is. class LikesController < ApplicationController def create @user = current_user @site = Site.find(params[:site_id]) @like = @site.likes.create!(params[:like]) @like.user = current_user @like.save respond_to do |format| format.html { redirect_to @site} format.js end end end This code successfully passes the like and site_id but after many different variations of trying I can't get it to pass the question id. Here is my form: /views/sites/_site.html.erb (though the partial is being displayed in the /views/questions/show.html.erb file). <% remote_form_for [site, Like.new] do |f| %> <%= f.hidden_field :site_name, :value => "#{site.name}" %> <%= f.hidden_field :ip_address, :value => "#{request.remote_ip}" %> <%= f.hidden_field :like, :value => "1" %> <%= submit_tag "^" , :class => 'voteup' %> <% end %>

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• Shortest Distance From An Array

  - by notyou61

  I have an ajax function which returns the latitudes and longitudes of locations stored in a database. These are returned and placed in an array. A calculation is performed to return their distance from the users current location based on the latitude/longitude. I would like to return only the record with the shortest calculated distance. My code is as follows: Ajax Success // Success success: function (data) { // Obtain Log/Lat navigator.geolocation.getCurrentPosition(function(position) { // Obtain Current Position Lat/Lon glbVar.latitude = position.coords.latitude; glbVar.longitude = position.coords.longitude; // Console Log //console.log('Lat: ' + glbVar.latitude + ' Lon: ' + glbVar.longitude); // Obtain Location Distances for ( var i = 0; i < data.length; i++ ) { // Location Instances var varLocation = data[i]; // Location Distance varLocation.distance = calculateDistance(glbVar.longitude, glbVar.latitude, varLocation.locationLongitude, varLocation.locationLatitude); } // Sort Locations By Distance var sortedData = data.sort(function(a, b) { // Return Locations return a.distance - b.distance; }); // Output Results $.map(sortedData, function(item) { // Obtain Location Distance varLocationsDistance = calculateDistance(glbVar.longitude, glbVar.latitude, item.locationLongitude, item.locationLatitude); // Obtain Location Radius Assignment if (varLocationsDistance <= varLocationRadius) { // Function Return functionReturn = $({locationID : item.locationID + ', Distance : ' + varLocationsDistance + ' m'}); // Return // Function to get the Min value in Array Array.min = function( sortedData ){ functionReturn = Math.min.apply( Math, sortedData ); // console.log(functionReturn); }; } }); }); } The calculateDistance function returns the distance from the users current location and those from the database. The varLocationsDistance <= varLocationRadius "If" statement returns records within a certain distance radius (100 meters), within that statement I would like to return the shortest distance. I am a self taught amateur web developer and as a result may not have provide enough information for an answer, please let me know. Thanks,

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• dynamic inheritance without touching classes

  - by Jasper

  I feel like the answer to this question is really simple, but I really am having trouble finding it. So here goes: Suppose you have the following classes: class Base; class Child : public Base; class Displayer { public: Displayer(Base* element); Displayer(Child* element); } Additionally, I have a Base* object which might point to either an instance of the class Base or an instance of the class Child. Now I want to create a Displayer based on the element pointed to by object, however, I want to pick the right version of the constructor. As I currently have it, this would accomplish just that (I am being a bit fuzzy with my C++ here, but I think this the clearest way) object->createDisplayer(); virtual void Base::createDisplayer() { new Displayer(this); } virtual void Child::createDisplayer() { new Displayer(this); } This works, however, there is a problem with this: Base and Child are part of the application system, while Displayer is part of the GUI system. I want to build the GUI system independently of the Application system, so that it is easy to replace the GUI. This means that Base and Child should not know about Displayer. However, I do not know how I can achieve this without letting the Application classes know about the GUI. Am I missing something very obvious or am I trying something that is not possible?

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• What database options do I have for the Blackberry?

  - by peeping-jane

  I notice most of the discussions about Blackberry database options are old, and generally not too informative. As of today, March 31st, 2010, what is the best, most universally supported, free database option available for Blackberry developers? I heard SQLite is available for JDE v5, but last I checked, that was still in beta, and I didn't want to commit to developing on a system that is not supported by most of the phones in service. Thing is, I don't see any dates on these claims. For all I know, the announcements I am reading are from 2008. So, I am still on v 4.7. I need to use a relational DB for the app I am developing, but there aren't many resources for DB handling available - or at least resources that are useful to me. I find a lot of "tutorials" that assume you know everything there is to know about Blackberry development, or Java. But no complete classes or anything. Many of these examples don't even work. Eclipse gives warnings and errors from code copied and pasted from other people's examples. I can answer any questions that may assist in this case. Hopefully, this thread will help many BB developers in the future.

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• smart phone UI limitations

  - by Manny

  I would like to know, what limitations there are for how far one can go in terms of replacing UI components of current touch screen smart phones, in particular iPhone, Blackberry and android based phones. What I would like to do is create a custom UI for dialing out and incoming calls. I have some experience with Blackberry development. The theme builder for it, can be used to customize certain items on the incoming call screen, but it doesn't look like that you can increase the size of answer button. I know Blackberry also gives you access to all the phone APIs, but I'm not sure that you can create your own UI that can gain preference over the Blackberry incoming call screen. And if you try to customize the incoming call screen by adding any buttons to it, they would be rendered as pictures. I could possibly design a complete UI for android, since different manufactures have different UI for android based phones. Can I do what I want to do using iPhone, Blackberry or android? Or any other phone for that matter? I am guessing may be for Nokia phones using Qt, but I prefer the 3 platforms I listed. Thanks for all your help.

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• Adding a ActionPerformed Array to a String Array

  - by user267490

  Hey, Before you guys ask, yes I've searched online for the answer, but everything I found just leaves a lil confuse and nothing is recent so asking in those forums won't really help. My problems is this: I have an array that holds my name for a menu. String[] fontColor = new String[] {"Red", "Blue", "Green"}; for (int i = 0; i < fontColors.length; i++) { JMenuItem fontC = new JMenuItem(fontColors[i]); fontC.addActionListener(new fontColorAction()); changeFontColor.add(fontC); } Then I have an array that holds my color change in a class called fontColorAction in that class I have another array that does the same thing as my string array except all thats in the statement is textarea.setForeground(colorArr[i]); that will set the setForeground() in order, but now how do I successfully attact the action listner in my class to my menuItems? my class looks like this private class fontColorAction implements ActionListener { Color[] colorArr - new Color[] {"Color.RED","Color.BLUE","Color.GREEN"}; public void actionPerformed(ActionEvent e){ for(i = 0; i < collorArr.length; i++){ textarea.setForeground(colorArr[i]); } } }

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• Passing.getText() String to another class

  - by DanMc

  I'm currently working on a first year university project and I have a problem, although I doubt it's a very complicated one, but I've been searching and I just can't find a suitable answer to it. The problem concerns two classes. A gui class (class1) and another class (class2). I have a JTextField in class1 and am trying to pass through the .getText() value to class2 and store it in a String type variable. The current code I'm trying to achieve this with is the following: (Class1) private JTextField textField = new JTextField("Something"); ... public String getTextFieldString() { return textField.getText(); } (Class2) private c1 Class1 = new Class1(); private String s = new String(); ... s = c1.getTextFieldString(); I'm pretty new to coding, I've read that maybe I need to pass through an argument somewhere and I assume that's because textField is not static in itself, it changes when somebody enters a new value. (sorry for stating the obvious there.) Anyway, help is appreciated. Thanks a lot!

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• Sys. engineer has decided to dynamically transform all XSLs into DLLs on website build process. DLL

  - by John Sullivan

  Hello, OS: Win XP. Here is my situation. I have a browser based application. It is "wrapped" in a Visual Basic application. Our "Systems Engineer Senior" has decided to spawn DLL files from all of our XSL pages (many of which have duplicate names) upon building a new instance of the website and have the active server pages (ASPX) use the DLL instead. This has created a "known issue" in which ~200 DLL naming conflicts occur and, thus, half of our application is broken. I think a solution to this problem is that, thankfully, we're generating the names of the DLLs and linking them up with our application dynamically. Therefore we can do something kludgy like generate a hash and append it to the end of the DLL file name when we build our website, then always reference the DLL that had some kind of random string / hash appended to its name. Aside from outright renaming the DLLs, is there another way to have multiple DLLs with the same name register for one application? I think the answer is "No, only between different applications using a special technique." Please confirm. Another question I have on my mind is whether this whole idea is a good practice -- converting our XSL pages (which we use in mass -- every time a response from our web app occurs) into DLL functions that call a "function" to do what the XSL page did via an active server page (ASPX), when we were before just sending an XML response to an XSL page via aspx.

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• WIN32 Logon question

  - by Lalit_M

  We have developed a ASP.NET 3.5 web application with Web Server 2008 and has implemented a custom authentication solution using active directory as the credentials store. Our front end application uses a normal login form to capture the user name and password and leverages the Win32 LogonUser method to authenticate the user’s credentials. When we are calling the LogonUser method, we are using the LOGON32_LOGON_NETWORK as the logon type. The issue we have found is that user profile folders are being created under the C:\Users folder of the web server. The folder seems to be created when a new user who has never logged on before is logging in for the first time. As the number of new users logging into the application grows, disk space is shrinking due to the large number of new user folders getting created. I need to get the token back after the authentication (authenticated \ password locked \ wrong password ) its futher use and based on logic showing different web pages Has anyone seen this behavior with the Win32 LogonUser method? Please answer the following issue: Is it possible to disable this behavior to create the folder as taking 2.78 MB of space for every new user and it eating my disck space? I have tried LOGON32_LOGON_BATCH but it was giving an error 1385 in authentication user. For any solution related to LOGON32_LOGON_BATCH, can you please confirm if that will stop creating the folders at location C:\users. Also for any possible solution I need either I am able to disable the folder to be created at C:\user or Any other option to authenticated user which will not creat folders.

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• Getting all the classes in project and their packages from CodeRush extension

  - by drasto

  I've spent some time trying to find a way CodeRush could add using when it finds undeclared element that is in the fact class name with no using added. The solution suggested in this answer to my question (Refactor_resolve) does not work (bugged?). In a process I found out that writing plug-ins for CodeRush is easy, so I decided to code this functionality myself (and share it). I'd only implement a CodeProvider (like in this tutorial). The only thinks I need to do the job are answers to this questions: At the start up of my plugin I need to get a list (set, map, whatever) of all classes and their packages. This means all the classes(interfaces...) and their packages in project, and within all referenced libraries. And I also need to receive updated on this (when user adds reference, creates new class). Can I get this from some CodeRush classes or maybe VS interface available from CodeProvider class? How do I add created CodeProvider to the pop-up that is shown when user hovers over an Issue?

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• Why is Excel's 'Evaluate' method a general expression evaluator?

  - by jtolle

  A few questions have come up recently involving the Application.Evaluate method callable from Excel VBA. The old XLM macro language also exposes an EVALUATE() function. Both can be quite useful. Does anyone know why the evaluator that is exposed can handle general expressions, though? My own hunch is that Excel needed to give people a way to get ranges from string addresses, and to get the value of named formulas, and just opening a portal to the expression evaluator was the easiest way. (The help for the VBA version does say its purpose it to "convert a Microsoft Excel name to an object or a value".) But of course you don't need the ability to evaluate arbitrary expressions just to do that. (That is, Excel could provide a Name.Evaluate method or something instead.) Application.Evaluate seems kind of...unfinished. It's full behavior isn't very well documented, and there are quite a few quirks and limitations (as described by Charles Williams here: http://www.decisionmodels.com/calcsecretsh.htm) with what is exposed. I suppose the answer could be simply "why not expose it?", but I'd be interested to know what design decisions led to this feature taking the form that it does. Failing that, I'd be interested to hear other hunches.

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• Java queue and multi-dimension array

  - by javaLearner.java

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

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• MySQL Join/Comparison on a DATETIME column (<5.6.4 and > 5.6.4)

  - by Simon

  Suppose i have two tables like so: Events ID (PK int autoInc), Time (datetime), Caption (varchar) Position ID (PK int autoinc), Time (datetime), Easting (float), Northing (float) Is it safe to, for example, list all the events and their position if I am using the Time field as my joining criteria? I.e.: SELECT E.*,P.* FROM Events E JOIN Position P ON E.Time = P.Time OR, even just simply comparing a datetime value (taking into consideration that the parameterized value may contain the fractional seconds part - which MySQL has always accepted) e.g. SELECT E.* FROM Events E WHERE E.Time = @Time I understand MySQL (before version 5.6.4) only stores datetime fields WITHOUT milliseconds. So I would assume this query would function OK. However as of version 5.6.4, I have read MySQL can now store milliseconds with the datetime field. Assuming datetime values are inserted using functions such as NOW(), the milliseconds are truncated (<5.6.4) which I would assume allow the above query to work. However, with version 5.6.4 and later, this could potentially NOT work. I am, and only ever will be interested in second accuracy. If anyone could answer the following questions would be greatly appreciated: In General, how does MySQL compare datetime fields against one another (consider the above query). Is the above query fine, and does it make use of indexes on the time fields? (MySQL < 5.6.4) Is there any way to exclude milliseconds? I.e. when inserting and in conditional joins/selects etc? (MySQL 5.6.4) Will the join query above work? (MySQL 5.6.4) EDIT I know i can cast the datetimes, thanks for those that answered, but i'm trying to tackle the root of the problem here (the fact that the storage type/definition has been changed) and i DO NOT want to use functions in my queries. This negates all my work of optimizing queries applying indexes etc, not to mention having to rewrite all my queries. EDIT2 Can anyone out there suggest a reason NOT to join on a DATETIME field using second accuracy?

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• Are Thread.stop and friends ever safe in Java?

  - by Stephen C

  The stop(), suspend(), and resume() in java.lang.Thread are deprecated because they are unsafe. The Sun recommended work around is to use Thread.interrupt(), but that approach doesn't work in all cases. For example, if you are call a library method that doesn't explicitly or implicitly check the interrupted flag, you have no choice but to wait for the call to finish. So, I'm wondering if it is possible to characterize situations where it is (provably) safe to call stop() on a Thread. For example, would it be safe to stop() a thread that did nothing but call find(...) or match(...) on a java.util.regex.Matcher? (If there are any Sun engineers reading this ... a definitive answer would be really appreciated.) EDIT: Answers that simply restate the mantra that you should not call stop() because it is deprecated, unsafe, whatever are missing the point of this question. I know that that it is genuinely unsafe in the majority of cases, and that if there is a viable alternative you should always use that instead. This question is about the subset cases where it is safe. Specifically, what is that subset?

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• How do I ignore an "invalid" SSL certificate in Objective-C?

  - by ipwnstuff

  Currently I have: NSArray* array = [NSArray arrayWithObjects:@"auth.login",@"username",@"password", nil]; NSData* packed_array = [array messagePack]; NSURL* url = [NSURL URLWithString:@"https://192.168.1.149:3790/api/1.0"]; NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:url]; [request setHTTPMethod:@"POST"]; [request setValue:@"RPC Server" forHTTPHeaderField:@"Host"]; [request setValue:@"binary/message-pack" forHTTPHeaderField:@"Content-Type"]; [request setValue:[NSString stringWithFormat:@"%d",[packed_array length]] forHTTPHeaderField:@"Content-Length"]; [request setHTTPBody:packed_array]; NSURLResponse *response; NSError *error; responseData = [NSMutableData dataWithData:[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]]; NSLog(@"response data: %@",[responseData messagePackParse]); NSLog(@"error: %@",error); - (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace { NSLog(@"called canAuthenticateAgainstProtectionSpace"); return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]; } - (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge { NSLog(@"called didReceiveAuthenticationChallenge"); [challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge]; } Which returns "Error Domain=NSURLErrorDomain Code=-1202 "The certificate for this server is invalid"…" How should I be implementing the answer from this question?

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