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• Get Data from Windows Form into C# program

  - by Jimmy

  I want my C# program to collect data. Then, when the OK button is clicked, I want this data to be loaded into my program -- such as into variables in Main(), or into data members of a class I have constructed, and I want the form to then go away -- not be hidden, but actually closed. Alas, read as I might in the book I have, the data collected by the form stays in the form, execution proceeds within the form, and the same form is used to display the result of the program's computations. Sheesh. All I want is to capture the form's information, close the form and proceed with my program. I would appreciate some tips on geting data from a form into Main() or into a class's data members. Thanks, Lucky

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• C++ associative array with arbitrary types for values

  - by Gerald Kaszuba

  What is the best way to have an associative array with arbitrary value types for each key in C++? Currently my plan is to create a "value" class with member variables of the types I will be expecting. For example: class Value { int iValue; Value(int v) { iValue = v; } std::string sValue; Value(std::string v) { sValue = v; } SomeClass *cValue; Value(SomeClass *v) { cValue = c; } }; std::map<std::string, Value> table; A downside with this is you have to know the type when accessing the "Value". i.e.: table["something"] = Value(5); SomeClass *s = table["something"].cValue; // broken pointer Also the more types that are put in Value, the more bloated the array will be. Any better suggestions?

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• I don't get this C/C++ Joke

  - by Buttercup

  After reading this article on thedailywtf.com, I'm not sure that I really got the joke. It says there that some guy changed the code from int function() { int x; char data_string[15]; ... x = 2; strcpy(data_string,"data data data"); ... } to int function() { int x = 2; char data_string[15] = "data data data"; ... } everywhere in the code and that for some reason did inflate the size of the executable from 1 to 2 CDs (or maybe it didn't do that?). Obviously I'm not familiar enough with C/C++ to get this joke, but what seems strangest is that the 2nd code listing seems "cleaner"—at least from what I've been told in school (that is that initializing variables is a good thing, not a bad one).

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• How to download files directly to disk on the iPhone os?

  - by favo

  Hi, I would like to download files directly from an URL to the disk using objective-c on the iPhone os. Currently I am using NSURLConnection to send a synchronousRequest, writing the returned NSData into a file. How can I change the download handling (still having the request beeing synchronous, it is already in a background thread) to write the data directly to disk, not using memory variables to store the complete content (only small parts)? A sample code would be appreciated. Thank you all in advance for your responses!

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• Is it inefficient to access a python class member container in a loop statement?

  - by Dave

  Hi there. I'm trying to adopt some best practices to keep my python code efficient. I've heard that accessing a member variable inside of a loop can incur a dictionary lookup for every iteration of the loop, so I cache these in local variables to use inside the loop. My question is about the loop statement itself... if I have the following class: class A(object): def init(self) self.myList = [ 'a','b','c', 'd', 'e' ] Does the following code in a member function incur one, or one-per-loop-iteration (5) dictionary lookups? for letter in self.myList: print letter IE, should I adopt the following pattern, if I am concerned about efficiency... localList = self.myList for letter in localList: print letter or is that actually LESS efficient due to the local variable assign? Note, I am aware that early optimization is a dangerous pitfall if I'm concerned about the overall efficiency of code development. Here I am specifically asking about the efficiency of the code, not the coding. Thanks in advance! D

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• Why is volatile not considered useful in multithreaded C or C++ programming?

  - by Michael E

  As demonstrated in this answer I recently posted, I seem to be confused about the utility (or lack thereof) of volatile in multi-threaded programming contexts. My understanding is this: any time a variable may be changed outside the flow of control of a piece of code accessing it, that variable should be declared to be volatile. Signal handlers, I/O registers, and variables modified by another thread all constitute such situations. So, if you have a global int foo, and foo is read by one thread and set atomically by another thread (probably using an appropriate machine instruction), the reading thread sees this situation in the same way it sees a variable tweaked by a signal handler or modified by an external hardware condition and thus foo should be declared volatile (or, for multithreaded situations, accessed with memory-fenced load, which is probably a better a solution). How and where am I wrong?

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• If I don't odr-use a variable, can I have multiple definitions of it across translation units?

  - by sftrabbit

  The standard seems to imply that there is no restriction on the number of definitions of a variable if it is not odr-used (§3.2/3): Every program shall contain exactly one definition of every non-inline function or variable that is odr-used in that program; no diagnostic required. It does say that any variable can't be defined multiple times within a translation unit (§3.2/1): No translation unit shall contain more than one definition of any variable, function, class type, enumeration type, or template. But I can't find a restriction for non-odr-used variables across the entire program. So why can't I compile something like the following: // other.cpp int x; // main.cpp int x; int main() {} Compiling and linking these files with g++ 4.6.3, I get a linker error for multiple definition of 'x'. To be honest, I expect this, but since x is not odr-used anywhere (as far as I can tell), I can't see how the standard restricts this. Or is it undefined behaviour?

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• Factory vs instance constructors

  - by Neil N

  I can't think of any reasons why one is better than the other. Compare these two implementations: public class MyClass { public myClass(string fileName) { // some code... } } as opposed to: public class MyClass { private myClass(){} public static Create(string fileName) { // some code... } } There are some places in the .Net framework that use the static method to create instances. At first I was thinking, it registers it's instances to keep track of them, but regular constructors could do the same thing through the use of private static variables. What is the reasoning behind this style?

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• FETCH INTO doesn't raise an exception if the set is empty, does it?

  - by Cade Roux

  Here is some actual code I'm trying to debug: BEGIN OPEN bservice (coservice.prod_id); FETCH bservice INTO v_billing_alias_id, v_billing_service_uom_id, v_summary_remarks; CLOSE bservice; v_service_found := 1; -- An empty fetch is expected for some services. EXCEPTION WHEN OTHERS THEN v_service_found := 0; END; When the parametrized cursor bservice(prod_id) is empty, it fetches NULL into the three variables and does not throw an exception. So whoever wrote this code expecting it to throw an exception was wrong, right? The comment seems to imply that and empty fetch is expected and then it sets a flag for later handling, but I think this code cannot possibly have been tested with empty sets either. Obviously, it should use bservice%NOTFOUND or bservice%FOUND or similar.

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• Rails Variable across all controller actions

  - by bob

  Hello, This should be a very simple rails question. I have a variable like the following. @administration = Administration.first I want this variable to be accessible through every controller action across all my controllers so for example if I have a Product controller and inside of it I have the usual CRUD actions, I want the @administration variable as defined above to be put into all the CRUD actions. (It would not be needed in destroy or create or update). I have many controllers throughout my project and I was wondering if there is an easier way than adding it manually through all of the actions that I want it in. I tried a global variable $administration = Administration.first but I run into an issue where it is not updated when I update the actual content of the Administration.first table. Also, I would like to avoid global variables. Any help would be much appreciated. Thanks! :)

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• Cache images provided through script

  - by Wim Haanstra

  I have a script, which by using several querystring variables provides an image. I am also using URL rewriting within IIS 7.5. So images have an URL like this: http://mydomain/pictures/ajfhajkfhal/44/thumb.jpg or http://mydomain/pictures/ajfhajkfhal/44.jpg This is rewritten to: http://mydomain/Picture.aspx?group=ajfhajkfhal&id=44&thumb=thumb.jpg or http://mydomain/Picture.aspx?group=ajfhajkfhal&id=44 I added caching rules to IIS to cache JPG images when they are requested. This works with my images that are REAL images on the disk. When images are provided through the script, they are somehow always requested through the script, without being cached. The images do not change that often, so if the cache at least is being kept for 30 minutes (or until file change) that would be best. I am using .NET/C# 4.0 for my website. I tried setting several cache options in C#, but I cant seem to find how to cache these images (client-side), while my static images are cached properly.

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• C++ cin returns 0 for integer no matter what the user inputs

  - by kevin dappah

  No matter the cin it continues to to output 0 for score. Why is that? I tried returning the "return 0;" but still no go :/ #include "stdafx.h" #include <iostream> using namespace std; // Variables int enemiesKilled; const int KILLS = 150; int score = enemiesKilled * KILLS; int main() { cout << "How many enemies did you kill?" << endl; cin >> enemiesKilled; cout << "Your score: " << score << endl; return 0; }

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• MySQL thousands of updates, slowing down.

  - by noryb009

  I need to run a PHP loop for a total of 100, 000 times (about 10, 000 each script-run), and each loop has about 5 MySQL UPDATES to it. When I run the loop 50 times, it takes 3 sec. When I run the loop 1000 times, it takes about 1300 sec. As you can see, MySQL is slowing down ALOT with more UPDATEs. This is an example update: mysql_query("UPDATE table SET `row1`=`row1` +1 WHERE `UniqueValue`='5'"); This is generated randomly from PHP, but I can store it in a variable and run it every n loops. Is there any way to either make MySQL and PHP run at a consistent speed (is PHP storing hidden variables?), or split up the script so they do? Note: I am running this for a development purposes, not for production, so there will only be 1 computer accessing the data.

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• Should I always release self for failed init methods?

  - by leo

  Should I always release self when there is a failure inside init, or should I only do so if I have initialized instance variables first? To put it another way, is this pattern valid? Is there a time when I shouldn't release self inside an init method, or should I assume that if the control flow enters init, self has at least a retain count of 1? - (id)init { if ((self = [super init]) == nil) { [self release]; return nil; } //do some init stuff if (somethingFailed) { [self release]; return nil; } return self; }

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• Does C++ require a destructor call for each placement new?

  - by Josh Haberman

  I understand that placement new calls are usually matched with explicit calls to the destructor. My question is: if I have no need for a destructor (no code to put there, and no member variables that have destructors) can I safely skip the explicit destructor call? Here is my use case: I want to write C++ bindings for a C API. In the C API many objects are accessible only by pointer. Instead of creating a wrapper object that contains a single pointer (which is wasteful and semantically confusing). I want to use placement new to construct an object at the address of the C object. The C++ object will do nothing in its constructor or destructor, and its methods will do nothing but delegate to the C methods. The C++ object will contain no virtual methods. I have two parts to this question. Is there any reason why this idea will not work in practice on any production compiler? Does this technically violate the C++ language spec?

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• Time difference in seconds (as a floating point)

  - by pocoa

  >>> from datetime import datetime >>> t1 = datetime.now() >>> t2 = datetime.now() >>> delta = t2 - t1 >>> delta.seconds 7 >>> delta.microseconds 631000 Is there any way to get that as 7.631000 ? I can use time module, but I also need that t1 and t2 variables as DateTime objects. So if there is a way to do it with datettime, that would be great.

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• JSP Component Creation

  - by jboyd

  When creating JSP pages one thing that I'd often like is the ability to do something like this: <jsp:include page="fancystoryrenderer.jsp" value="${aStoryObjectInMyModel}/> ... fancystoryrenderer.jsp <div id="fancymainbody"> ... ${theStory.title} ... </div> The main important characteristics of this is that I can reuse the same component on the same JSP page in different places without having to copy paste the component and give the story variables different names, notice that the story is called "theStory" in the JSP and not "aStoryObjectInMyModel", the linkage between our model has been broken by the view, which is a good thing in this case How do you do this?

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• What is the explanation for "warning: assuming that the loop is not infinite"

  - by James Morris

  I had just taken the decision to change as many variables from unsigned to int and upon recompiling the code in question, was greeted by this warning message: freespace_state.c:203: warning: assuming that the loop is not infinite The line in question: for (x = startx; x <= endx; ++x, ++xptr) This loop is 60 lines of code (inc white space/brackets etc), and has a goto within it, and at least one occurrence of continue. In this case, I think I am appreciative that GCC is assuming this loop is not infinite, because, it should never loop indefinitely. What is GCC trying to tell me here?

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• Do I need to install Glassfish?

  - by Ayusman

  Hi, I am new to glassfish server. i have a question on glassfish usage: can I just use glassfish like a tomcat server without needing an installation? where in, I just take a folder containing glassfish folders, jars etc... dump it in a folder location setup a few environment variables and it runs.. just like tomcat? is it possible with glassfish? also does glassfish installation does any other background things like creating registry entries etc other than creating the glassfish folder structure? TIA Ayusman

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• Is this an injection attempt or a normal request?

  - by CheeseConQueso

  In cPanel's Analog Stats statistics module, I've noticed countless requests to connect to the following example: /?x=19&y=15 The numbers are random, but its always setting x and y variables. Another category of mysterious requests: /?id=http://nic.bupt.edu.cn/media/j1.txt?? There are other attempts at injections in the request log that have straight sql written into them as well. Example: /jobs/jobinfo.php?id=-999.9 UNION ALL SELECT 1,(SELECT concat(0x7e,0x27,count(table_name),0x27,0x7e) FROM information_schema.tables WHERE table_schema=0x73636363726F6F745F7075626C6963),3,4,5,6,7,8,9,10,11,12,13-- It looks like they are all reaching a 404, but I'm still wondering about the intent behind these. I know this is vague, but maybe someone knows that this is normal while using cPanel & phpMyAdmin services. Also, there was a search box installed on the site which could be the reason. Any suggestions as to what all these are?

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• What is good practice for writing web applications that control daemons (and their config files)

  - by Jones R

  Can someone suggest some basic advice on dealing with web applications that interact with configuration files like httpd.conf, bind zone files, etc. I understand that it's bad practice, in fact very dangerous to allow arbitrary execution of code without fully validating it and so on. But say you are tasked to write a small app that allows one to add vhosts to an apache configuration. Do you have your code execute with full privileges, do you write future variables into a database and have a cron job (with full privileges) execute a script that pulls the vars from the database and throws them into a template config file, etc. Some thoughts & contributions on this issue would be appreciated. tl;dr - how can you securely write a web app to update/create entries in a config file like apache's httpd.conf, etc.

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• VBA long overflow

  - by HK_CH

  Hi I am trying to do some maths with my VBA excel (prime factorization) and I am hitting the limit of the long data type (runtime error 6 Overflow). Is there any way to get around this and still stay within VBA? (I am aware that the obvious one would be to use another more appropriate programming language) Thanks for help in advance! Thank you, it works in so far that I am able to get the big numbers into the variables now. However when I try to apply the MOD function (bignumber MOD 2 for example) it still fails with error message runtime error 6 Overflow.

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• PHP split string into integer element and string

  - by David19801

  Hello, I have a string say: Order_num = "0982asdlkj" How can I split that into the 2 variables, with the number element and then another variable with the letter element in php? The number element can be any length from 1 to 4 say and the letter element fills the rest to make every order_num 10 characters long in total. I have found the php explode function...but don't know how to make it in my case because the number of numbers is between 1 and 4 and the letters are random after that, so no way to split at a particular letter. Please help as specifically as possible!

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• Using Components.utils.import in a firefox extension

  - by jamesatha

  I am trying to create some global variables in a firefox extension. In my content folder, I have two javascript files: 1) Main JS file that holds the functions for the different events, etc 2) A file that stores only an object with the pieces of state I want to maintain. Also, I set the array EXPORTED_SYMBOLS. I am having issues with the following line found in my main JS file: Components.utils.import("resource:///globalVariables.js"); When it is at the top of the file, nothing seems to work. If I move it into the function where I need the variable, the rest of my code works, but the function with this line does nothing. Any advice that would help me with this problem would be great. Thanks

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• C string program

  - by mrblippy

  Hi, i have been given a task to do ar school that must read three strings in, store the third string in dynamically allocated memory and print out the last 4 letters of the first word alphabetically. Here is the program i have so far but the strings are all stored in different variables, making them hard to sort. if anyone could give me a hand and help me finish this program i would be very grateful. thanks #include <stdio.h> #include <stdlib.h> #include <string.h> int main() { char word1[101]; char word2[101]; char* word3; char buffer[101]; scanf("%s", word1); scanf("%s", word2); scanf("%s", buffer); word3 = (char *) malloc(strlen(buffer)+1); strcpy(word3, buffer); return 0; }

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