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• GoTo statements and alternatives in VB.NET

  - by qais

  I've posted a code snippet on another forum asking for help and people pointed out to me that using GoTo statements is very bad programming practice. I'm wondering: why is it bad? What alternatives to GoTo are there to use in VB.NET that would be considered generally more of a better practice? Consider this snippet below where the user has to input their date of birth. If the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if there's a better way to do this, I'd appreciate if you could tell me that also :D) How would I be able to loop back to ask the user again? retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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• Why is Postgres doing a Hash in this query?

  - by Claudiu

  I have two tables: A and P. I want to get information out of all rows in A whose id is in a temporary table I created, tmp_ids. However, there is additional information about A in the P table, foo, and I want to get this info as well. I have the following query: SELECT A.H_id AS hid, A.id AS aid, P.foo, A.pos, A.size FROM tmp_ids, P, A WHERE tmp_ids.id = A.H_id AND P.id = A.P_id I noticed it going slowly, and when I asked Postgres to explain, I noticed that it combines tmp_ids with an index on A I created for H_id with a nested loop. However, it hashes all of P before doing a Hash join with the result of the first merge. P is quite large and I think this is what's taking all the time. Why would it create a hash there? P.id is P's primary key, and A.P_id has an index of its own.

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• Handling of data truncation (short reads/writes) in FUSE

  - by Vi

  I expect any good program should do all their reads and writes in a loop until all data written/read without relying that write will write everything (even with regular files). Am I right? Implemented simple FUSE filesystem which only allows reading and writing with small buffers, very often returning that it is written less bytes that in a buffer (using -o direct_io). Some programs work, some not (notably mountlo). Are them buggy or programs should not expect truncated writes and reads from the regular files? In general, are seekable file descriptors expected to truncate data like sockets and pipes?

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• Reusing a vector in C++

  - by Bobby

  I have a vector declared as a global variable that I need to be able to reuse. For example, I am reading multiple files of data, parsing the data to create objects that are then stored in a vector. vector<Object> objVector(100); void main() { while(THERE_ARE_MORE_FILES_TO_READ) { // Pseudocode ReadFile(); ParseFileIntoVector(); ProcessObjectsInVector(); /* Here I want to 'reset' the vector to 100 empty objects again */ } } Can I reset the vector to be "vector objVector(100)" since it was initially allocated on the stack? If I do "objVector.clear()", it removes all 100 objects and I would have a vector with a size of 0. I need it to be a size of 100 at the start of every loop.

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• check whether fgets would block

  - by lv

  Hi, I was just wondering whether in C is it possible to peek in the input buffer or perform similar trickery to know whether a call to fgets would block at a later time. Java allows to do something like that by calling BufferedReader.ready(), this way I can implement console input something like this: while (on && in.ready()) { line = in.readLine(); /* do something with line */ if (!in.ready()) Thread.sleep(100); } this allows an external thread to gracefully shutdown the input loop by setting on to false; I'd like to perform a similar implementation in C without resorting to non portable tricks, I already know I can make a "timed out fgets" under unix by resorting to signals or (better, even though requering to take care of buffering) reimplement it on top of recv/select, but I'd prefer something that would work on windows too. TIA

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• how to keep the value of a variable in a closure

  - by Florian Fida

  i need to create multiple javascript functions which have a static id inside, so the function itself knows what data to process. Here is some code: (function(){ function log(s){ if(console && console.log) console.log(s); else alert(s); } var i = 10; while (i--){ window.setTimeout(function(){ // i need i to be 10, 9, 8... here not -1 log(i); },500); } })(); The problem ist that i allways gets updated by the loop, and i need to prevent this. Thanks in advance for any help, comments or tips!

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• Basic QT Event handling / Threading questions ?

  - by umanga

  Greetings , I am new to QT (4.6) and have some basic questions regarding its event mechanism.I come from Swing background so I am trying to compare it with QT. 1) Does Event-processing-loop run in seperate thread? (like EventDispatch thread in Swing) ? 2) If we open several 'QMainWindow' do they run in several threads? 3) Whats the best way to run an intensive process in a seperate thread? (like SwingWorker in Swing ? ) 4) If intesive-process runs in a seperate thread ,is it possible to call UI methods like update(),repaint() from that process? thanks in advance.

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• [C#] How to create a constructor of a class that return a collection of instances of that class?

  - by codemonkie

  My program has the following class definition: public sealed class Subscriber { private subscription; public Subscriber(int id) { using (DataContext dc = new DataContext()) { this.subscription = dc._GetSubscription(id).SingleOrDefault(); } } } ,where _GetSubscription() is a sproc which returns a value of type ISingleResult<_GetSubscriptionResult> Say, I have a list of type List<int> full of 1000 ids and I want to create a collection of subscribers of type List<Subscriber>. How can I do that without calling the constructor in a loop for 1000 times? Since I am trying to avoid switching the DataContext on/off so frequently that may stress the database. TIA.

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• Why use a do-end block in Lua?

  - by Mayron

  I keep trying to find answers for this but fail to do so. I wanted to know, what is the do-end block actually used for? It just says values are used when needed in my book so how could I use this? Do I use it to reduce the scope of local variables by placing a function in a do-end loop and place local variables outside of the function but inside this do-end block and the variables will be seen by the function? But then can the function still be called? Sorry for being very vague. I hope that makes sense. Maybe an illustrated example might be useful ^^

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• simple rank formula

  - by Graham

  I'm looking for a mathmatical ranking formula. Sample is 2008 2009 2010 A 5 6 4 B 6 7 5 C 7 8 2 I want to add a rank column for each period code field rank 2008 2009 2010 2008 2009 2010 B 6 7 5 2 1 1 A 5 6 4 3 2 2 C 7 2 2 1 3 3 please do not reply with methods that loop thru the rows and columns, incrementing the rank value as it goes, that's easy. I'm looking for a formula much like finding the percent total (item / total). I know i've seen this before but an havning a tough time locating it. Thanks in advance!

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• c style thread creation in python

  - by chandank

  Hi I am new to python and want to create multiple threads in a loop something like (in C style) for (;i < 10; i++) thread[i]= pthread_create(&thread[i],&attr,func) I am not sure how to do the same in python? Basically I want have that thread[] variable as global will create all thread at once and then will start then in once. I have written a similar python program that does it but I think having it in above style will be better. def thread_create(thread_number): command_string = "Thread-" + "%d" %thread_number thread = myThread(thread_number, command_string) thread.start() # Start new Threads for i in range(5): thread_create(i)

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• Is there a better way to do SELECT queries in MySQL and sort them in PHP than this way?

  - by Kent

  I am just learning PHP/MySQL, one this I am having to do a lot is displaying data that was previously inserted into the database out to the user's browser. So I am doing this: $select = mysql_query('SELECT * FROM pages'); while ($return = mysql_fetch_assoc($select)) { $title = $return['title']; $author = $return['author']; $content = $return['content']; } then I can use these variables through out the page. Now, doing it the above way isn't an issue when I only have 3 columns in a database but what if I am dealing with a huge database with many more columns. I have a nagging feeling that the pros do it in some more efficient way where they maybe loop through the table they are selecting from to find all columns it has and associate them with variables automatically. Is that the case? or is the above how you guys do it too?

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• Python breaks for a certain amount

  - by Brian Cox

  All, I am not very good at explaining so i will let my comments do it! #this script is to calculate some of the times table up to 24X24 and also miss some out #Range of numbers to be calculated numbers=range(1,25) for i in numbers: for w in numbers: print(str(i)+"X"+str(w)+"="+str(i*w)) #here i want to break randomly (skip some out) e.g. i could be doing the 12X1,12X2 and then 12X5 i have no limit of skips. Update Sorry if this is not clear i want it to break from the inner loop for a random amount of times

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• I wired up a z 80 using telephone wire and put a jump to 0000 0000 0000 0000

  - by john

  I put 1100 0011 0000 0000 0000 0000 in the 2764 eprom --- this is supposed to test the z80 -- I have a 555 timer running at 500 khz. Can this small program work with the z80 ? I looked at the address pins on a m465 oscilloscope. The address shows highs up to 0100 0000. I think it should only count to 0000 0000 0000 0011. Can the z80 be tested? The Santa Clara Valley also made the lm1871 radio control chip that could not show a high or a low without completing the entire rc loop.

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• What happens to an instance of ServerSocket blocked inside accept(), when I drop all references to i

  - by Hanno Fietz

  In a multithreaded Java application, I just tracked down a strange-looking bug, realizing that what seemed to be happening was this: one of my objects was storing a reference to an instance of ServerSocket on startup, one thread would, in its main loop in run(), call accept() on the socket while the socket was still waiting for a connection, another thread would try to restart the component under some conditions, the restart process missed the cleanup sequence before it reached the initialization sequence as a result, the reference to the socket was overwritten with a new instance, which then wasn't able to bind() anymore the socket which was blocking inside the accept() wasn't accessible anymore, leaving a complete shutdown and restart of the application as the only way to get rid of it. Which leaves me wondering: with no references left to the ServerSocket instance, what would free the socket for a new connection? At what point would the ServerSocket become garbage collected? In general, what are good practices I can follow to avoid this type of bug?

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• Display PHP Query Array in the table

  - by Jerry

  Hi all I would like to display my Query from Mysql on the table. However, my data is like this: Array([0]=>data1, [1]=>data2, [2]=>data3,[3]=>data4,[4]=>pic1,[5]=>pic2,[6]=>pic3,[7]=>pic4); I want to display my table as |data1 | data2 |data3 |data4 |pic1 | pic2 |pic3 |pic4 I know how to display the data in the single ling like td or tr but not sure how to do tr and td on the same loop. Any helps? Thanks in advance! while($query=mysql_fetch_array($dataQuery)){ //not sure what to do here. }

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• How to retrieve large data from oracle database using vbscript

  - by allenzzzxd

  Hi guys, I'm now working on vbscript to do some test. Actuelly, I want to retrieve a large amount of data from an oracle database, so I write the code like this: sql = "Select * from CORE_DB where MC = '" & mstr & "' " Set myrs = db_execute_query(curConnection, sql) Then I count the rows in myrs,there are 248 rows. So then I do a For loop to retrieve some fields of each row. For k = 0 To db_get_rows_count(myrs) But then I found that the content of the row k when k 133 was always equal to k = 133. So this makes an error. As I think, there may be a limit size of mrys ? Could anyone light me about this? Thanks a lot in advance

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• Nested pound sign problem

  - by Ray Buechler

  I'm having an issue when I try to nest pound signs in my ColdFusion code. I keep getting the following error message: Invalid CFML construct found on line 57 at column 26. ColdFusion was looking at the following text: # Here is the code: <cfloop index="i" from="1" to="12"> <cfset needRecord.setNeed#i#(#form["need#i#"]#) /> </cfloop> If I run the loop outside the cfset tag like this: <cfloop index="i" from="1" to="12"> needRecord.setNeed#i#(#form["need#i#"]#) </cfloop> The code runs and generates what I would like to generate within the cfset tag. Any idea what I'm doing wrong? Any help would be greatly appreciated.

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• get all fields value from mysql using php

  - by zahir hussain

  hi i want to know how to get all fields value search by array. i have array that s my table is id content 1 zahr 2 hai . . . and so on $a = {2,3,4,5,43,32}; i have to take the contents by this id(from array "a"). i know, i can use "for" loop for getting each element from mysql. but i would like to use any filters or any predefined function thanks and advance

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• [java] Threading socket handler for two sided communication in tcp port

  - by raven

  I want to make a chat which will be programed in java. one computer will host the server and the other one will initiate the socket [tcp port]. now from what I read there should be a loop that will constantly read the socket which means it will make the code stuck. I have a button that is 'actionperformed' on mouse release, I want to know if it will work along with the loops that constantly reads the socket so that it will also send the infromation I wrote. If I must thread it, I want to know if the run() method must be void because if I thread it it will mean creating a new class, and the whole GUI is one big class which includes a text area, and it's private. also how can I extract the information from the socket directly to the text area? lets say the textarea variable is called "chatOutput". thx :)

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• Dynamically adding Views in Silverlight & MVVM

  - by dvox

  Hi all, I am starting to re-write my whole silverlight business application in the MVVM pattern; My first stop-point is this: I have a page (View1) with corresponding ViewModel1 (with a property 'IEnumerable AllData'); Now, within this View, I want to have i.e. a tree-view control, in which one node will be populated with another View2; My question is: 1. How to do it? - I can't loop through the AllData property since it is asynchronously loaded... - thus I don't know the number of View2s' to insert - I don't know how to do it from ViewModel1 :( Will I need ViewModel2 with property 'MyDataEntity CurrentData'? or I can bind to AllData property from ViewModel1 Can you help me out? Thanks

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• Highest populated dimension of an array vba

  - by Ommit

  Say i have an single dimension array (to keep it simple). Is there a simple way to tell how many entries are populated, or the highest dimension of populated entries, other than to loop through and count them? I know Ubound finds the highest dimension of the array but that's not what I need. Is there something like Ubound but it only find populated entries, or the highest dimension populated? Also, what if the array is multidimensional. I'm working in excel vba.

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• C++ streams question (explanation of comment in code)

  - by skyeagle

  I am playing around with the fastCGI application found here. The following comment is in the code: if (content) delete []content; // If the output streambufs had non-zero bufsizes and // were constructed outside of the accept loop (i.e. // their destructor won't be called here), they would // have to be flushed here. My knowledge of C++ streams is rather weak. Could someone please explain the following: which streambufs are being referred to in the comment? under what conditions would the streambufs had non-zero bufsizes? last but not the least, can someone point to a resource (pun intended) online that provides a clear but gentle introduction to C++ IO streams?

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• Looking for suggestions about an architecture of a MultiThreaded app.

  - by Dimitri

  Hello everyone. I am looking to develop a multithreaded application that will be running in unconditional loop and processing high volume of data. High volume is 2000+ records per minute. Processing will involve data retrieval, calculations and data updates. I need the application to perform so that there is virtually no back log, meaning i need to be able to finish up all of the 2000 points in one minute or even faster. Our current implementation features a multithreaded application that is spawn multiple times (from 10 to 20) and we are noticing that it's not handling data as expected and i even feel that instances of the application compete with each other for processor time and eventually if not slowing, not benefiting each other for sure. I would like to know what would be the best approach: have a single instance running but maximize threads that can run simultaneously? or is there other ways i don't know? I'm open to suggestions. Thank you in advance

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• How to define a function which repeats itself when passed an argument

  - by ~unutbu

  Is there an easy way to define a function which repeats itself when passed an argument? For example, I've defined the following function (defun swap-sign () (interactive) (search-forward-regexp "[+-]") (if (equal (match-string 0) "-") (replace-match "+") (replace-match "-")) ) I'd like C-u swap-sign to call swap-sign four times. I've tried (defun swap-sign (&optional num) (interactive) (let ((counter 0) (num (if num (string-to-number num) 0))) (while (<= counter num) (search-forward-regexp "[+-]") (if (equal (match-string 0) "-") (replace-match "+") (replace-match "-")) (setq counter (1+ counter))))) but C-u swap-sign still only runs swap-sign (or perhaps more precisely, the body of the while-loop) once. I'm guessing it is because if num is not the right way to test if num is an empty string. Am I on the right track, or is there a better/easier way to extend swap-sign?

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