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• how to reverse an angle

  - by MissHalberd

  I am no mathematician, but I somehow got into game development as a hobby. Having never studied anything beyond basic math, I have a lot of trouble figuring out how to reverse the angle of something, facing to the opposite direction, among the X axis. One image says more than 1000 words though (specially uneducated words): http://img156.imageshack.us/i/wihwin.png/ I basically want to reverse the direction of cannon objects adhered to a robot. When the robot changes from facing right to facing left, I do (180 - angle) as everyone suggested me, but it reverses the angle...literally, making the cannons aim up when they are aiming down. So, I need to do something else, but it escapes my knowledge. Anyone would be so kind to help me with this? Oh, I use regular C by the way, in case there's something built-in specific to it. To put it in other words, I work in 2D, so I want an angle that is facing right to face left. 0 being "totally to the right", 180 "left", 90 "up" and 270 "down". I want something that is aiming with an angle of 91 to turn into 89 when reversed, literally. There's no Z axis present. EDIT: Thanks for the answers! Trying them out now. I'll post which one worked in a minute!

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• Explaining a Ruby code snippet

  - by Michael Foukarakis

  I'm in that uncomfortable position again, where somebody has left me with a code snippet in a language I don't know and I have to maintain it. While I haven't introduced Ruby to myself some parts of it are quite simple, but I'd like to hear your explanations nonetheless. Here goes: words = File.open("lengths.txt") {|f| f.read }.split # read all lines of a file in 'words'? values = Array.new(0) words.each { |value| values << value.to_i } # looked this one up, it's supposed to convert to an array of integers, right? values.sort! values.uniq! diffs = Array.new(0) # this looks unused, unless I'm missing something obvious sum = 0 s = 0 # another unused variable # this looks like it's computing the sum of differences between successive # elements, but that sum also remains unused, or does it? values.each_index { |index| if index.to_i < values.length-1 then sum += values.at(index.to_i + 1) - values.at(index.to_i) end } # could you also explain the syntax here? puts "delta has the value of\n" # this will eventually print the minimum of the original values divided by 2 puts values.at(0) / 2 The above script was supposed to figure out the average of the differences between every two successive elements (integers, essentially) in a list. Am I right in saying this is nowhere near what it actually does, or am I missing something fundamental, which is likely considering I have no Ruby knowledge?

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• filtering search results with php

  - by fl3x7

  Hello, Cant really find any useful information on this through Google so hope someone here with some knowledge can help. I have a set of results which are pulled from a multi dimensional array. Currently the array key is the price of a product whilst the item contains another array which contains all the product details. key=>Item(name=>test, foo=>bar) So currently when I list the items I just order by the key, smallest first and it lists the products smallest price first. However I want to build on this so that when a user sees the results they can choose other ordering options like list all products by a name, certain manufacturer, colour, x ,y ,z etc etc from a drop down box(or something similar) This is where I need some guidance. Im just not sure how to go about it or best practise or anything. The only way I can think of is to order all the items by the nested array eg by the name, manufacturer etc. but how do I do that in PHP? Hope you understand what im trying to achieve(if not just ask). Any help on this with ideas, approaches or examples would be great. Thanks for reading p.s Im using PHP5

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• MySQL table doesn't update, can't find the error message

  - by mobius1ski

  My knowledge level here is like zilch, but please bear with me. I have a site built in PHP/MySQL that uses the Smarty template engine. There's a registration form that, for some reason, isn't posting the data to the DB. Here's the function: $u = new H_User; $u->setFrom($p); $smarty->assign('user', $u); $val = $u->validate(); if ($val === true) { $temp = new H_User; $temp->orderBy('user_id desc'); $temp->find(true); $next_id = $temp->user_id + 1; $u->user_id = $next_id; $u->user_password = md5($p['user_password']); $u->user_regdate = mktime(); $u->user_active = 0; $u->insert(); $hash = md5($u->user_email . $u->user_regdate); $smarty->assign('hash', $hash); $smarty->assign('user', $u); $smarty->assign('registration_complete', true); $d = new H_Demographic; $d->setFrom($p); $d->insert(); How can I figure out what's wrong here? I don't get any PHP errors and I don't know how to get MySQL to display the errors that might indicate what's wrong with that syntax.

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

  - by aener

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

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• How to ask questions to an obstructionist?

  - by Rob Wells

  This is not related to my other recently posted question about "working with a star developer". In a similar vein, how do you work with someone who will only answer the specific question that you ask. I worked with someone who, when you asked a question on a specific aspect of the system, would give you the answer just related to the specific bit you'd asked about. For example, when processing radar messages I'd ask about an aspect of message number RJ546 and he would answer just about that specific part of RJ546. He wouldn't mention anything about the other freaky parts of the message, or mention any related aspects of the other messages. Then you'd go off and work on the processing and all of a sudden all this other freakiness would pop up. What's a good technique when working with this type of person? BTW I later found out that the person who I'd come in to replace had quit because he got sick and tired of having these surprises pop up due to the lack of information provided by this person. Edit: I forgot to add that the person was deliberately obstructionist and believed that job security came from hoarded knowledge not being disseminated.

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• Most effecient way to create a "slider" timeline in HTML, CSS, and JavaScript?

  - by ZapChance

  Alright, so here's my dilemma. I've got these two "slides" lined up, one ready to be passed into view. I have it working and all, but I can scroll over to the right to see the second slide! How could I have it you can only view the one slide? JavaScript used: function validate(form) { var user = form.username.value; var pass = form.password.value; if(user === "test") { if(pass === "pass") { var hideoptions = {"direction" : "left", "mode" : "hide"}; var showoptions = {"direction" : "left", "mode" : "show"}; /*$("#loginView").toggle("slide", hideoptions, 1000, function() { $("#loginView").css("margin-left", "100%"); }); $("#mainView").toggle("slide", showoptions, 1000, function() { $("#mainView").css("margin-left", 0); });*/ $("#loginView").animate({ marginLeft: "-100%" }, 1000); $("#mainView").animate({ marginLeft: "0" }, 1000); } else { alert("nope"); } } else { alert("nope 2"); } } As you can see here @ http://jsfiddle.net/D7Va3/1/ (JSFiddle), once you enter "test" and "pass", then click enter, the tiles slide. But. If you reload, you can see that you can scroll to the right of the screen and view the second slide prematurely, which is just not going to work for me. I still need to achieve the same seamless transition, but you must only be able to view one slide at a time. Also, I plan to expand with more slides, so if you're feeling lucky today, I'd really love to see an example of how I could support multiple frames. I'm very new to JavaScript (yet I know syntax rules, and general coding knowledge from other languages), so the better you explain, the more knowledgeable I can be, and I'd be very grateful for that. Thanks in advance!

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• Framework or CMS for php web development?

  - by rocknroll

  Hi all, I am a C++,Unix developer who has never dabbled in web development apart from creating simple HTML pages. I am going to change that and develop a website at a personal level soon. I am going to use php,mysql on a linux machine. In this regard I am browsing through relevant literature. The language isn't a problem but reading about CMS's and frameworks is confusing. And since I am new to web development, the number of CMS's and Frameworks are overwhelming. ? My question is do I need to have knowledge of one or more CMS' and/or Frameworks like Drupal,Joomla,Zend,Wordpress etc. If yes which is the best open source CMS' and/or Framework suggested for a newbie. ?? If the answer to the above question is yes, does the choice changes if one delves into the realms of commercial web development? Note:- I will be developing on a Linux machine, using open source tools. Thanks in advance

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• Need help on HttpWebrequest

  - by ASPUSER

  HI Guys I have the same issue and I am looking to solve it. Here is detail I have two web sites WebsiteA and WebSiteB (WebsiteB is not in my control, A type of black box for me.). Both websites have seprate login page I have alist of users,password of websiteB which I stored in database. I want a kind of common login page. If user is login to websiteA and he want to go to websiteB, he dont have to enter the login and password information again. I can not touch the code of websiteB. it's alredy deployed and runing. In websiteB in login form they have a Userid textbox and Password textbox and and a login Button. This butoon is not a submit button. It has a click event which calls a function to validate the user. it's not a simple post. WebsiteB has one webpage which has different frames. After login sucessfull. The pages doesnt go to any other page it remain on the same page but load the different frame. According to my knowledge. I can use httpwebrequest class. But faceing the following problem. Can not click the button. Response.Redirect does not work. It seems that WebsiteB is not storing any thing in cookies as cookies always return me a empty string I really appriciate if anyone can help me on it. How Can I use response.Redirect . As when I redirect it shows me the same login page.

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• PHP download script for "processes running limited" hosting (eg. hostgator)

  - by Joe

  I am currently with HostGator on a shared hosting plan. I have a new website I'm trying to setup with a download.php script. The issue I am having is that, while someone is "downloading" a file through the download.php script, it counts as a "process" and my hosting plan limits the processes that can be running at the same time to 25 at present. My question is, what options do I have? a). Move to new web hosting that doesn't limit processes running. b). Change the way files are downloaded. I would like to choose option b), however it occurs to me that I need to have the file accessed through PHP in order to restrict the number of downloads and to track download statistics, as well as protecting against hotlinking. If there was a way to have the PHP script send them the file so that the process doesn't need to be running the whole time the file is being downloaded, I would eliminate the problem, however to my knowledge that isn't possible. Should I make the move to a new hosting company? I really enjoy HostGator as they have provided the best hosting experience for me thus far, except for this one issue of course, so I don't want to go on the hunt for another decent shared hosting company that doesn't limit processes running, only to find out there is another restriction or "catch" to the shared hosting deal.

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• How do I compare 2 fields and return the lowest value of each record?

  - by BigRob

  I'm slowly learning access to make a database of products and suppliers for my parents' business. What i've got is a table of products indexed by our product reference and 2 more tables for 2 different suppliers that contains the suppliers product reference and price that links with our reference. I've made a query that performs a left outer join such that it returns a table of our products with each supplier's reference and price, i.e: Ref | Product Name | Supplier 1 Ref | Supplier 1 Price | Supplier 2 Ref | Supplier 2 Price Here's the query I used: SELECT Catalog.Ref, Catalog.[Product Name], Catalog.Price, [D Products].[Supplier Ref], [D Products].Cost, [GS Products].[Supplier Ref], [GS Products].Cost FROM ([Catalog] LEFT JOIN [D Products] ON Catalog.Ref = [D Products].Ref) LEFT JOIN [GS Products] ON Catalog.Ref = [GS Products].Ref; Not all products are available from both suppliers, hence the outer join. What I want to do (with a query?) is to take the table produced by the query above and simply show the product reference, cheapest supplier reference and cheapest supplier price, i.e: Ref | Cheapest Suppplier Ref | Cheapest Supplier Price Unfortunately my SQL knowledge isn't quite good enough to figure this out, but if anyone can help i'd really appreciate it. Thanks, Rob

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• Cryptography for P2P card game

  - by zephyr

  I'm considering writing a computer adaptation of a semi-popular card game. I'd like to make it function without a central server, and I'm trying to come up with a scheme that will make cheating impossible without having to trust the client. The basic problem as I see it is that each player has a several piles of cards (draw deck, current hand and discard deck). It must be impossible for either player to alter the composition of these piles except when allowed by the game rules (ie drawing or discarding cards), nor should players be able to know what is in their or their oppponent's piles. I feel like there should be some way to use something like public-key cryptography to accomplish this, but I keep finding holes in my schemes. Can anyone suggest a protocol or point me to some resources on this topic? [Edit] Ok, so I've been thinking about this a bit more, and here's an idea I've come up with. If you can poke any holes in it please let me know. At shuffle time, a player has a stack of cards whose value is known to them. They take these values, concatenate a random salt to each, then hash them. They record the salts, and pass the hashes to their opponent. The opponent concatenates a salt of their own, hashes again, then shuffles the hashes and passes the deck back to the original player. I believe at this point, the deck has been randomized and neither player can have any knowledge of the values. However, when a card is drawn, the opponent can reveal their salt, allowing the first player to determine what the original value is, and when the card is played the player reveals their own salt, allowing the opponent to verify the card value.

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• nothrow or exception ?

  - by Muggen

  I am a student and I have small knowledge on C++, which I try to expand. This is more of a philosophical question.. I am not trying to implement something. Since #include <new> //... T * t = new (std::nothrow) T(); if(t) { //... } //... Will hide the Exception, and since dealing with Exceptions is heavier compared to a simple if(t), why isn't the normal new T() not considered less good practice, considering we will have to use try-catch() to check if a simple allocation succeeded (and if we don't, just watch the program die)?? What are the benefits (if any) of the normal new allocation compared to using a nothrow new? Exception's overhead in that case is insignificant ? Also, Assume that an allocation fails (eg. no memory exists in the system). Is there anything the program can do in that situation, or just fail gracefully. There is no way to find free memory on the heap, when all is reserved, is there? Incase an allocation fails, and an std::bad_alloc is thrown, how can we assume that since there is not enough memory to allocate an object (Eg. a new int), there will be enough memory to store an exception ?? Thanks for your time. I hope the question is in line with the rules.

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• Codeigniter : database configuration

  - by nppCods

  I am beginner for CI so don’t have good knowledge. My problem is: I am not using any database. All the records are fetched from JSON. Therefore I don’t think I need to configure database… As said by CI, it doesn’t necessarily ask for database. So my database.php configuration is : $active_group = ‘default’; $active_record = FALSE; $db[‘default’][‘hostname’] = ‘’; $db[‘default’][‘username’] = ‘’; $db[‘default’][‘password’] = ‘’; $db[‘default’][‘database’] = ‘’; $db[‘default’][‘dbdriver’] = ‘mysql’; $db[‘default’][‘dbprefix’] = ‘’; $db[‘default’][‘pconnect’] = TRUE; $db[‘default’][‘db_debug’] = TRUE; $db[‘default’][‘cache_on’] = FALSE; $db[‘default’][‘cachedir’] = ‘’; $db[‘default’][‘char_set’] = ‘utf8’; $db[‘default’][‘dbcollat’] = ‘utf8_general_ci’; $db[‘default’][‘swap_pre’] = ‘’; $db[‘default’][‘autoinit’] = TRUE; $db[‘default’][‘stricton’] = FALSE; It works in my local system but doesn’t work in live server. I am so surprised. Then I provided hostname, username, password and dbdriver, it works. My question is that, is that necessary to provide all the details if I am not using database? Thank you for your suggestion.

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• MySql: Is it reasonable to use 'view' or I would better denormalize my DB?

  - by Budda

  There is 'team_sector' table with following fields: Id, team_id, sect_id, size, level It contains few records for each 'team' entity (referenced with 'team_id' field). Each record represent sector of team's stadium (totally 8 sectors). Now it is necessary to implement few searches: by overall stadium size (SUM(size)); the best quality (SUM(level)/COUNT(*)). I could create query something like this: SELECT TS.team_id, SUM(TS.size) as OverallSize, SUM(TS.Level)/COUNT(TS.Id) AS QualityLevel FROM team_sector GROUP BY team_id ORDER BY OverallSize DESC / ORDER BY QualityLevel DESC But my concern here is that calculation for each team will be done each time on query performed. It is not too big overhead (at least now), but I would like to avoid performance issues later. I see 2 options here. The 1st one is to create 2 additional fields in 'team' table (for example) and store there OverallSize and QualityLevel fields. If information if 'sector' table is changed - update those table too (probably would be good to do that with triggers, as sector table doesn't change too often). The 2nd option is to create a view that will provide required data. The 2nd option seems much easier for me, but I don't have a lot of experience/knowledge of work with views. Q1: What is the best option from your perspective here and why? Probably you could suggest other options? Q2: Can I create view in such way that it will do calculations rarely (at least once per day)? If yes - how? Q3: Is it reasonable to use triggers for such purpose (1st option). P.S. MySql 5.1 is used, overall number of teams is around 1-2 thousand, overall number of records in sector table - overall 6-8 thousand. I understand, those numbers are pretty small, but I would like to implement the best practice here.

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• How to learn a new programming language? And how to choose the appropriate language?

  - by Sebi

  Unfortunately my last question was closed, so I reformulated the question: I know this question was here a lot of times and can't be answered at all, but im not looking for a single name, but rather for an advice in my situation. I learned programming with Java and now I'm developing in Java for more or less 5 years (at the university) and I thinks my programming skills their are really ok/average. I have also small experience in C/C++ and C#. Now I have some spare time and I'd like to learn a new language or deepen the knowledge of Java/C/C++. But how to choose the right language to learn? I'd like to learn a language which will be usefull in the future concerning working in a software development business? I know there is no single answer, but I'm sure you could mention some languages that are more usefull than others. And what's the best way to learn such a language efficiently (bearing in mind that one has already learned some other languages)? Just doing tutorials? Or trying to implement a project? Trying to move a Java project to the new language?

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• How can pointers to functions point to something that doesn't exist in memory yet? Why do prototypes have different addresses?

  - by Kacy Raye

  To my knowledge, functions do not get added to the stack until run-time after they are called in the main function. So how can a pointer to a function have a function's memory address if it doesn't exist in memory? For example: using namespace std; #include <iostream> void func() { } int main() { void (*ptr)() = func; cout << reinterpret_cast<void*>(ptr) << endl; //prints 0x8048644 even though func never gets added to the stack } Also, this next question is a little less important to me, so if you only know the answer to my first question, then that is fine. But anyway, why does the value of the pointer ( the memory address of the function ) differ when I declare a function prototype and implement the function after main? In the first example, it printed out 0x8048644 no matter how many times I ran the program. In the next example, it printed out 0x8048680 no matter how many times I ran the program. For example: using namespace std; #include <iostream> void func(); int main() { void ( *ptr )() = func; cout << reinterpret_cast<void*>(ptr) << endl; } void func(){ }

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• VB Change Calulator

  - by BlueBeast

  I am creating a VB 2008 change calculator as an assignment. The program is to use the amount paid - the amount due to calculate the total.(this is working fine). After that, it is to break that amount down into dollars, quarters, dimes, nickels, and pennies. The problem I am having is that sometimes the quantity of pennies, nickels or dimes will be a negative number. For example $2.99 = 3 Dollars and -1 Pennies. SOLVED Thanks to the responses, here is what I was able to make work with my limited knowledge. Option Explicit On Option Strict Off Option Infer Off Public Class frmMain Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click 'Clear boxes lblDollarsAmount.Text = String.Empty lblQuartersAmount.Text = String.Empty lblDimesAmount.Text = String.Empty lblNickelsAmount.Text = String.Empty lblPenniesAmount.Text = String.Empty txtOwed.Text = String.Empty txtPaid.Text = String.Empty lblAmountDue.Text = String.Empty txtOwed.Focus() End Sub Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click 'Close application' Me.Close() End Sub Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click ' Find Difference between Total Price and Total Received lblAmountDue.Text = Val(txtPaid.Text) - Val(txtOwed.Text) Dim intChangeAmount As Integer = lblAmountDue.Text * 100 'Declare Integers Dim intDollarsBack As Integer Dim intQuartersBack As Integer Dim intDimesBack As Integer Dim intNickelsBack As Integer Dim intPenniesBack As Integer ' Change Values Const intDollarValue As Integer = 100 Const intQuarterValue As Integer = 25 Const intDimeValue As Integer = 10 Const intNickelValue As Integer = 5 Const intPennyValue As Integer = 1 'Dollars intDollarsBack = CInt(Val(intChangeAmount \ intDollarValue)) intChangeAmount = intChangeAmount - Val(Val(intDollarsBack) * intDollarValue) lblDollarsAmount.Text = intDollarsBack.ToString 'Quarters intQuartersBack = CInt(Val(intChangeAmount \ intQuarterValue)) intChangeAmount = intChangeAmount - Val(Val(intQuartersBack) * intQuarterValue) lblQuartersAmount.Text = intQuartersBack.ToString 'Dimes intDimesBack = CInt(Val(intChangeAmount \ intDimeValue)) intChangeAmount = intChangeAmount - Val(Val(intDimesBack) * intDimeValue) lblDimesAmount.Text = intDimesBack.ToString 'Nickels intNickelsBack = CInt(Val(intChangeAmount \ intNickelValue)) intChangeAmount = intChangeAmount - Val(Val(intNickelsBack) * intNickelValue) lblNickelsAmount.Text = intNickelsBack.ToString 'Pennies intPenniesBack = CInt(Val(intChangeAmount \ intPennyValue)) intChangeAmount = intChangeAmount - Val(Val(intPenniesBack) * intPennyValue) lblPenniesAmount.Text = intPenniesBack.ToString End Sub End Class

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• MS SQL: How to get the newest date in a table with several equal keys

  - by Qohelet

  Unfortunately my knowledge related to statements like "group by" and "having" is quite limited, so hopefully you can help me: I have a view -here's an excerpt- (if we have some Europeans here - it's v021 of Winline/Mesonic): ID | Artikelbezeichnung1 | Bez2 | mesoyear _____________________________________________________________________ 1401MA70 | Marga ,Saracena grigio,1S,33,3/33,3 | Marazzi | 1344 1401MA70 | Marga ,Saracena grigio,1S,33,3/33,3 | Marazzi | 1356 1401MA70 | Marga ,Saracena grigio,1S,33,3/33,3 | Marazzi | 1356 1401MA71 | Marga ,Saracena beige,1S,33,3/33,3 | Marazzi | 1344 1401MA71 | Marga ,Saracena beige,1S,33,3/33,3 | Marazzi | 1356 1401MA71 | Marga ,Saracena beige,1S,33,3/33,3 | Marazzi | 1356 2401CR13 | Crista,Mahon rojo,1S,33,3/33,3 | Cristacer | 1332 2401CR13 | Crista,Mahon rojo,1S,33,3/33,3 | Cristacer | 1344 So the ID is not unique and I just need the one with the highest val in "mesoyear". My fist solution was: Select c015 as ID, c003 as Artikelbezeichnung1, c074 as Bez2, mesoyear from CWLDATEN_91.dbo.v021 group by c015 having mesoyear = max(mesoyear) But this doesn't work at all... Msg 8121, Level 16, State 1, Line 8 Column 'CWLDATEN_91.dbo.v021.mesoyear' is invalid in the HAVING clause because it is not contained in either an aggregate function or the GROUP BY clause. So I just removed the "having" statement and it went "better": Msg 8120, Level 16, State 1, Line 2 Column 'CWLDATEN_91.dbo.v021.c003' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. So I tried to remove the error just by adding things to the "group by". And it worked. Select c015 as ID, c003 as Artikelbezeichnung1, c074 as Bez2, max(mesoyear) from CWLDATEN_91.dbo.v021 group by c015,c003,c074 gives me exactly what I want. But the correct Select contains about 24 columns and some calculations as well. The problem can't be solved just by adding all the columns to the "group by"...? Can someone please help me to find a proper command? Thank you!

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• Nested/Sub data types in haskell

  - by Tom Carstens

  So what would be nice is if you could do something like the following (not necessarily with this format, just the general idea): data Minor = MinorA | MinorB data Major = Minor | MajorB isMinor :: Major -> Bool isMinor Minor = True isMinor _ = False So isMinor MinorA would report True (instead of an error.) At the moment you might do something like: data Major = MinorA | MinorB | MajorB isMinor :: Major -> Bool isMinor MinorA = True isMinor MinorB = True isMinor _ = False It's not terrible or anything, but it doesn't expand nicely (as in if Minor when up to MinorZ this would be terribly clunky). To avoid that problem you can wrap Minor: data Minor = MinorA | MinorB data Major = MajorA Minor | MajorB isMinor :: Major -> Bool isMinor (MajorA _) = True isMinor _ = False But now you have to make sure to wrap your Minors to use them as a Major... again not terrible; just doesn't really express the semantics I'd like very well (i.e. Major can be any Minor or MajorB). The first (legal) example is "Major can be MinorA..." but doesn't have any knowledge of Minor and the second is "Major can be MajorA that takes a Minor..." p.s. No, this isn't really about anything concrete.

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• Compression Program in C

  - by Delandilon

  I want to compress a series of characters. For example if i type Input : FFFFFBBBBBBBCCBBBAABBGGGGGSSS (27 x 8 bits = 216 bits) Output: F5B7C2B3A2B2G5S3 (14 x 8 bits = 112bits) So far this is what i have, i can count the number of Characters in the Array. But the most important task is to count them in the same sequence. I can't seem to figure that out :( Ive stared doing C just a few weeks back, i have knowledge on Array, pointers, ASCII value but in any case can't seem to count these characters in a sequence. Ive try a bit of everything. This approach is no good but it the closest i came to it. #include <stdio.h> #include <conio.h> int main() { int charcnt=0,dotcnt=0,commacnt=0,blankcnt=0,i, countA, countB; char str[125]; printf("*****String Manipulations*****\n\n"); printf("Enter a string\n\n"); scanf("%[^'\n']s",str); printf("\n\nEntered String is \" %s \" \n",str); for(i=0;str[i]!='\0';i++) { // COUNTING EXCEPTION CHARS if(str[i]==' ') blankcnt++; if(str[i]=='.') dotcnt++; if(str[i]==',') commacnt++; if (str[i]=='A' || str[i]=='a') countA++; if (str[i]=='B' || str[i]=='b') countA++; } //PRINT RESULT OF COUNT charcnt=i; printf("\n\nTotal Characters : %d",charcnt); printf("\nTotal Blanks : %d",blankcnt); printf("\nTotal Full stops : %d",dotcnt); printf("\nTotal Commas : %d\n\n",commacnt); printf("A%d\n", countA); }

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• [PHP] Does unsetting array values during iterating save on memory?

  - by saturn_rising

  Hello fellow code warriors, This is a simple programming question, coming from my lack of knowledge of how PHP handles array copying and unsetting during a foreach loop. It's like this, I have an array that comes to me from an outside source formatted in a way I want to change. A simple example would be: $myData = array('Key1' => array('value1', 'value2')); But what I want would be something like: $myData = array([0] => array('MyKey' => array('Key1' => array('value1', 'value2')))); So I take the first $myData and format it like the second $myData. I'm totally fine with my formatting algorithm. My question lies in finding a way to conserve memory since these arrays might get a little unwieldy. So, during my foreach loop I copy the current array value(s) into the new format, then I unset the value I'm working with from the original array. E.g.: $formattedData = array(); foreach ($myData as $key => $val) { // do some formatting here, copy to $reformattedVal $formattedData[] = $reformattedVal; unset($myData[$key]); } Is the call to unset() a good idea here? I.e., does it conserve memory since I have copied the data and no longer need the original value? Or, does PHP automatically garbage collect the data since I don't reference it in any subsequent code? The code runs fine, and so far my datasets have been too negligible in size to test for performance differences. I just don't know if I'm setting myself up for some weird bugs or CPU hits later on. Thanks for any insights. -sR

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• RDS installation failure on 2012 R2 Server Core VM in Hyper-V Server

  - by Giles

  I'm currently installing a test-bed for my firms Infrastructure replacement. 10 or so Windows/Linux servers will be replaced by 2 physical servers running Hyper-V server. All services (DC, RDS, SQL) will be on Windows 2012 R2 Server Core VMs, Exchange on Server 2012 R2 GUI, and the rest are things like Elastix, MailArchiver etc, which aren't part of the equation thus far. I have installed Hyper-V server on a test box, and sucessfully got two virtual DC's running, SQL 2014 running, and 8.1 which I use for the RSAT tools. When trying to install RDS (The old fashioned kind, not the newer VDI(?) style), I get a failed installation due to the server not being able to reboot. A couple of articles have said not to do it locally, so I've moved on. Sitting at the Powershell prompt on the Domain Controller or SQL server (Both Server Core), I run the following commands: Import-Module RemoteDesktop New-SessionDeployment -ConnectionBroker "AlstersTS.Alsters.local" -SessionHost "AlstersTS.Alsters.local" The installation begins, carries on for 2 or 3 minutes, then I receive the following error message: New-SessionDeployment : Validation failed for the "RD Connection Broker" parameter. AlstersTS.Alsters.local Unable to connect to the server by using WindowsPowerShell remoting. Verify that you can connect to the server. At line:1 char:1 + NewSessionDeployment -ConnectionBroker "AlstersTS.Alsters.local" -SessionHost " ... + + CategoryInfo : NotSpecified: (:) [Write-Error], WriteErrorException + FullyQualifiedErrorID : Microsoft.PowerShell.Commands.WriteErrorException,New-SessionDeployment So far, I have: Triple, triple checked syntax. Tried various other commands, and a script to accomplish the same task. Checked DNS is functioning as it should. Checked to the best of my knowledge that AD is working as it should. Checked that the Network Service has the needed permissions. Created another VM and placed the two roles on different servers. Deleted all VMs, started again with a new domain name (Lather, rinse, repeat) Performed the whole installation on a second physical box running Hyper-V Server Pleaded with it Interestingly, if I perform the installation via a GUI installation, the thing just works! Now I know I could convert this to a Server Core role after installation, but this wouldn't teach me what was wrong in the first instance. I've probably got 10 pages through various Google searches, each page getting a little less relevant. The closest matches seem to have good information, but it doesn't seem to be the fix for my set-up. As a side note, I expected to be able to "tee" or "out-file" the error message into a text file, but couldn't get that to work either, so I've typed in the error message manually. Chaps, any suggestions, from the glaringly obvious, to the long-winded and complex? Thanks!

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• Cannot login to SQL Server 2008 R2 with Windows authentication

  - by Ian Boyd

  When i try to connect to SQL Server (2008 R2) using Windows authentication: i cannot: Checking the Windows Application event log, i find the error: Login failed for user 'AVATOPIA\ian'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT: ] Log Name: Application Source: MSSQLSERVER Event ID: 18456 Level: Information User: AVATOPIA\ian OpCode: Task Category: Logon i can login to the computer itself using Windows authentication. i can log into SQL Server using the local Windows Administrator account. We can connect to 8 other SQL Servers on the domain using Windows Authentication. Just this one, whitch is the only one that is 2008 R2 is failing. So i assume it's a bug with *2008 R2. Note: i cannot logon locally, or remotely, using Windows authentication. i can login locally and remotely using SQL Server Authentication. Update Note: It's not limited to SQL Server Management Studio, standalone applications that connect using Windows authentication: fail: Note: It's not a client problem, as we can connect fine to other (non-SQL Server 2008 R2 machines): i'm sure there's a technote or knowledge base article describing why SQL Server 2008 R2 is broken by default, but i can't find it. Update 2 Matt figure out the change that Microsoft made so that SQL Server 2008 R2 is broken by default: Administrators are no longer administrators All that remains is to figure out how to make Administrators administrators. One of these days i'm going to start a list of changes around Microsoft's "broken by default" initiative. Steps to reproduce the problem How do i add a group to the sysadmin fixed server role? Here's the steps i try, that don't work: Click Add: Click Object Types: Ensure that you have no ability to add groups: and click OK. Under Enter the object names to select, enter Administrators: Click Check Names, and ensure that you are not allowed to add groups: and click Cancel. Click Browse..., and ensure that you have no ability to add groups: You should now still not have added any group to the sysadmin role. Additional information SQL Server Management Studio is being run as an administrator: SQL Server is set to use Windows Authentication: tried while logged into SQL with both sa and the only other sysadmin domain account (screenshot can be supplied for those who don't believe)

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• How do I protect a low budget network from rogue DHCP servers?

  - by Kenned

  I am helping a friend manage a shared internet connection in an apartment buildling with 80 apartments - 8 stairways with 10 apartments in each. The network is laid out with the internet router at one end of the building, connected to a cheap non-managed 16 port switch in the first stairway where the first 10 apartments are also connected. One port is connected to another 16 port cheapo switch in the next stairway, where those 10 apartments are connected, and so forth. Sort of a daisy chain of switches, with 10 apartments as spokes on each "daisy". The building is a U-shape, approximately 50 x 50 meters, 20 meters high - so from the router to the farthest apartment it’s probably around 200 meters including up-and-down stairways. We have a fair bit of problems with people hooking up wifi-routers the wrong way, creating rogue DHCP servers which interrupt large groups of the users and we wish to solve this problem by making the network smarter (instead of doing a physical unplugging binary search). With my limited networking skills, I see two ways - DHCP-snooping or splitting the entire network into separate VLANS for each apartment. Separate VLANS gives each apartment their own private connection to the router, while DHCP snooping will still allow LAN gaming and file sharing. Will DHCP snooping work with this kind of network topology, or does that rely on the network being in a proper hub-and-spoke-configuration? I am not sure if there are different levels of DHCP snooping - say like expensive Cisco switches will do anything, but inexpensive ones like TP-Link, D-Link or Netgear will only do it in certain topologies? And will basic VLAN support be good enough for this topology? I guess even cheap managed switches can tag traffic from each port with it’s own VLAN tag, but when the next switch in the daisy chain receives the packet on it’s “downlink” port, wouldn’t it strip or replace the VLAN tag with it’s own trunk-tag (or whatever the name is for the backbone traffic). Money is tight, and I don’t think we can afford professional grade Cisco (I have been campaigning for this for years), so I’d love some advice on which solution has the best support on low-end network equipment and if there are some specific models that are recommended? For instance low-end HP switches or even budget brands like TP-Link, D-Link etc. If I have overlooked another way to solve this problem it is due to my lack of knowledge. :)

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