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• ISO/IEC Website and Charging for C and C++ Standards

  - by Michael Aaron Safyan

  The ISO C Standard (ISO/IEC 9899) and the ISO C++ Standard (ISO/IEC 14882) are not published online; instead, one must purchase the PDF for each of those standards. I am wondering what the rationale is behind this... is it not detrimental to both the C and C++ programming languages that the authoritative specification for these languages is not made freely available and searchable online? Doesn't this encourage the use of possibly inaccurate, non-authoritative sources for information regarding these standards? While I understand that much time and effort has gone into developing the C and C++ standards, I am still somewhat puzzled by the choice to charge for the specification. The OpenGroup Base Specification, for example, is available for free online; they make money buy charging for certification. Does anyone know why the ISO standards committees don't make their revenue in certifying standards compliance, instead of charging for these documents? Also, does anyone know if the ISO standards committee's atrociously looking website is intentionally made to look that way? It's as if they don't want people visiting and buying the spec. One last thing... the C and C++ standards are generally described as "open standards"... while I realize that this means that anyone is permitted to implement the standard, should that definition of "open" be revised? Charging for the standard rather than making it openly available seems contrary to the spirit of openness. P.S. I do have a copy of the ISO/IEC 9899:1999 and ISO/IEC 14882:2003, so please no remarks about being cheap or anything... although if you are tempted to say such things, you might want to consider the high school, undergraduate, and graduate students who might not have all that much extra cash. Also, you might want to consider the fact that the ISO website is really sketchy and they don't even tell you the cost until you proceed to the checkout... doesn't really encourage one to go and get a copy, now does it?

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• 500 Worker Threads, what kind of thread pool?

  - by Submerged

  I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing. ExecutorService es = Executors.newFixedThreadPool(list.size()+1); for (int i = 0; i < list.size(); i++) { es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects } The code that is executing is really simple and basically just this class aThread extends Thread { public void run(){ while(true){ Thread.sleep(ONE_MINUTE); //Lots of computation every minute } } } I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful! Well, the design is arguably flawed. The threads implement Genetic-Programming or GP, a type of learning algorithm. Each thread analyzes advanced trends makes predictions. If the thread ever completes, the learning is lost. That said, I was hoping that sleep() would allow me to share some of the resources while one thread isn't "learning"

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• How to link pnglite library in c?

  - by zaplec

  Hi, I installed from kubuntu's package management this handy pnglite library. It contains just one header file "pnglite.h" and one object file "pnglite.o". I have found out where those files are, but I don't know how to link them. I'm using netbeans, but don't know how to link them in there. Also I don't understand how to link them at console. I have a little test program that I would like to test, but I get the error message "undefined reference to function: XXXXXXX". Both netbeans and at console I'm using gcc. That header file is in /usr/include directory, object file is in /usr/lib directory and my test program is under my programming directory at my home directory. Should I put that header and object into the same directory as where my source is? Or is there a way to link them from their current locations? I know that it should be possible to link them from where they are at the moment and I would like to know and understand how to do that. Any help will be appreciated :)

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• Querying a database using Cocoa.

  - by S1syphus

  Hello everybody. Before I start a disclaimer, I should add a little disclaimer, that I am relatively new to Cocoa development and C in general. However I do have a copy of 'Cocoa Programming for Mac OS X 3rd edition' by Aaron Hillegass, which I am working through and using as a base, if anybody has a copy I am using the 'AmaZone' example on page 346 as a template and base. I trying to develop a small client app that takes a search string then displays results from a database accordingly. The database will contain a: list of files, their location, description & creation date, so for the moment the field number and types will remain the same. After looking around on SO, I saw something like: NSURL *myURL = [NSURL URLWithString:@"http://www.myserver.com/results.php"]; NSArray *sqlResults = [[NSArray alloc] initWithContentsOfURL:myURL]; I've worked with php before, so my current thinking after seeing this is create a php script on the server that queries the database, and creates an XML output. And with the XML response, just parse it. Would this be ok? as is there any major pitfalls anybody can see, that I can't. I know there are some database bundles, I've had a look at BaseTen for Postgres, but being relatively new to this, didn't want to get in over my head. Or if anybody else has any other suggestions and ideas, they would be greatly appreciated.

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• How should I start to play with 3D

  - by MarceloRamires

  I'm a developer for just about 6 months now, and since I enjoy programming I make a couple of little programs. I've startedmaking encripters, calculators, tools, stuff to play with DropBox (hehe), stuff that play with bitmaps, drawing graphics, and even a program to update the MSN display image according to the artwork of the music you're listening yo on iTunes. Now I kind of ran off ideas of programs to deal with information, and I've had an idea: play around with 3d! so I've read a little about it and figured I'd have to have good notions on position and math on point spacial position (which I do, from my 3d modelling experience), but I don't know how to use API's for it, so I've 'simulated' simple 3d with a simple program I've made (it's just a spinning cube, please, first one to open it, comment here stating that it's safe, i've got no reason to harm anyone's pc.) One of my other hobbies is 3d modelling (completly amateur) and I'd like to mix these hobbies together! Here are some questions: 1) What would be a nice 3d development tool for a .NET programmer like me? 2) Is there a way of using 3d models made in 3DS Max ? (I intend on modelling characters) 3) What knowledges should I have in order to render it, and move it areound ? 4) Which API should I use ? NOTE: Not a dupe, I'm asking for directions specific for .NET development possibly using 3ds MAX, and there's no question about it!

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• Does a CS PhD Help for Software Engineering Career?

  - by SiLent SoNG

  I would like to seek advice on whether or not to take a PhD offer from a good university. My only concern is the PhD will take at least 4 year's commitment. During the period I won't have good monetary income. I am also concerned whether the PhD will help my future career development. My career goal is software engineering only. Some of the PhD info: The PhD is CS related. The research area is Information Retrieval, Machine Learning, and Nature Language Processing. More specifically, the research topic is Deep Web search. Some of backgrounds: I worked in Oracle for 3 years in database development after obtained a CS degree from some good university. In last year I received an email telling an interesting project from a professor and thereafter I was lured into his research team. The team consists of 4 PhD students; those students have little or no industry experiences and their coding skills are really really bad. By saying bad I mean they do not know some common patterns and they do not know pitfalls of the programming languages as well as idioms for doing things right. I guess a at least 4 year commitment is worth of serious consideration. I am 27 at this moment. If I take the offer, that implies I will be 31+ upon graduation. Wah... becoming.. what to say, no longer young. Hence, here I am seeking advice on whether it is good or not to take the PhD offer, and whether a CS PhD is good for my future career growth as a software engineer? I do not intent to go for academia.

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• How to pass a function in a function?

  - by SoulBeaver

  That's an odd title. I would greatly appreciate it if somebody could clarify what exactly I'm asking because I'm not so sure myself. I'm watching the Stanford videos on Programming Paradigms(that teacher is awesome) and I'm up to video five when he started doing this: void *lSearch( void* key, void* base, int elemSize, int n, int (*cmpFn)(void*, void*)) Naturally, I thought to myself, "Oi, I didn't know you could declare a function and define it later!". So I created my own C++ test version. int foo(int (*bar)(void*, void*)); int bar(void* a, void* b); int main(int argc, char** argv) { int *func = 0; foo(bar); cin.get(); return 0; } int foo(int (*bar)(void*, void*)) { int c(10), d(15); int *a = &c; int *b = &d; bar(a, b); return 0; } int bar(void* a, void* b) { cout << "Why hello there." << endl; return 0; } The question about the code is this: it fails if I declare function int *bar as a parameter of foo, but not int (*bar). Why!? Also, the video confuses me in the fact that his lSearch definition void* lSearch( /*params*/ , int (*cmpFn)(void*, void*)) is calling cmpFn in the definition, but when calling the lSearch function lSearch( /*params*/, intCmp ); also calls the defined function int intCmp(void* elem1, void* elem2); and I don't get how that works. Why, in lSearch, is the function called cmpFn, but defined as intCmp, which is of type int, not int* and still works? And why does the function in lSearch not have to have defined parameters?

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• Formatting Parameters for Ajax POST request to Rails Controller - for jQuery-UI sortable list

  - by Hung Luu

  I'm using the jQuery-UI Sortable Connected Lists. I'm saving the order of the connected lists to a Rails server. My approach is to grab the list ID, column ID and index position of each list item. I want to then wrap this into an object that can be passed as a parameter back to the Rails Controller to be saved into the database. So ideally i'm looking to format the parameter like this: Parameters: {"Activity"=>[{id:1,column:2,position:1},{id:2,column:2,position:2} ,...]} How do I properly format my parameters to be passed in this Ajax POST request? Right now, with the approach below, I'm passing on Parameters: {"undefined"=>""} This is my current jQuery code (Coffeescript) which doesn't work: jQuery -> $('[id*="day"]').sortable( connectWith: ".day" placeholder: "ui-state-highlight" update: (event, ui) -> neworder = new Array() $('[id*="day"] > li').each -> column = $(this).attr("id") index = ui.item.index() + 1 id = $("#" + column + " li:nth-child(" + index + ") ").attr('id') passObject={} passObject.id = id passObject.column = column passObject.index = index neworder.push(passObject) alert neworder $.ajax url: "sort" type: "POST" data: neworder ).disableSelection() My apologies because this seems like a really amateur question but I'm just getting started with programming jQuery and Javascript.

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• how to implement a really efficient bitvector sorting in python

  - by xiao

  Hello guys! Actually this is an interesting topic from programming pearls, sorting 10 digits telephone numbers in a limited memory with an efficient algorithm. You can find the whole story here What I am interested in is just how fast the implementation could be in python. I have done a naive implementation with the module bitvector. The code is as following: from BitVector import BitVector import timeit import random import time import sys def sort(input_li): return sorted(input_li) def vec_sort(input_li): bv = BitVector( size = len(input_li) ) for i in input_li: bv[i] = 1 res_li = [] for i in range(len(bv)): if bv[i]: res_li.append(i) return res_li if __name__ == "__main__": test_data = range(int(sys.argv[1])) print 'test_data size is:', sys.argv[1] random.shuffle(test_data) start = time.time() sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "vec_sort function takes " + str(elapsed) I have tested from array size 100 to 10,000,000 in my macbook(2GHz Intel Core 2 Duo 2GB SDRAM), the result is as following: test_data size is: 1000 sort function takes 0.000274896621704 vec_sort function takes 0.00383687019348 test_data size is: 10000 sort function takes 0.00380706787109 vec_sort function takes 0.0371489524841 test_data size is: 100000 sort function takes 0.0520560741425 vec_sort function takes 0.374383926392 test_data size is: 1000000 sort function takes 0.867373943329 vec_sort function takes 3.80475401878 test_data size is: 10000000 sort function takes 12.9204008579 vec_sort function takes 38.8053860664 What disappoints me is that even when the test_data size is 100,000,000, the sort function is still faster than vec_sort. Is there any way to accelerate the vec_sort function?

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• How to accommodate for the iPhone 4 screen resolution?

  - by dontWatchMyProfile

  This is a programming question! Read on before you vote to close! According to Apple, the iPhone 4 has a new and better screen resolution: 3.5-inch (diagonal) widescreen Multi-Touch display 960-by-640-pixel resolution at 326 ppi This little detail affects our apps in a heavy way. Most of the demo apps on the net have one thing in common: They position views in the believe that the screen has a fixed size of 320 x 480 pixels. So what most -if not all- developers do is: They designed everything in such a way, that a touchable area is -for example- 50 x 50 pixels big. Just enough to tap it. Things have been positioned relative to the upper left, to reach a specific position on screen - let's say the center, or somewhere at the bottom. Edit: It seems Apple has integrated an switch that allows to tell if an app is highRes or not. Nice. When we develop high-resolution apps, they probably won't work on older devices. And if they do, they would suffer a lot from 4-times the size of any image, having to scale them down in memory.

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• Access violations in strange places when using Windows file dialogs

  - by Robert Oschler

  A long time ago I found out that I was getting access violations in my code due to the use of the Delphi Open File and/or Save File dialogs, which encapsulate the Windows dialogs. I asked some questions on a few forums and I was told that it may have been due to the way some programs add hooks to the shell system that result in DLLs getting injected in every process, some of which can cause havoc with a program. For the record, the programming environment I use is Delphi 6 Professional running on Windows XP 32-bit. At the time I got around it by not using Delphi's Dialog components and instead calling straight into comdlg32.dll. This solved the problem wonderfully. Today I was working with memory mapped files for the first time and sure enough, access violations started cropping up in weird parts of the code. I tried my comdlg32.dll direct calls and this time it didn't help. To isolate the problem as a test I created a list box with the exact same files I was using during testing. These are the exact same test files I was selecting from an Open File dialog and then launching my memory mapped file with. I set things up so that by clicking on a file in the list box, I would use that file in my memory mapped file test instead of calling into a comdlg32.dll dialog function to select a test file. Again, the access violatons vanished. To show you how dramatic a fix it was I went from experiencing an access violation within 1 to 3 trials to none at all. Unfortunately, it's going to bite me later on of course when I do need to use file dialogs. Has anyone else dealt with this issue too and found the real culprit? Did any of you find a solution I could use to fix this problem instead of dancing around it like I am now? Thanks in advance.

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• wxpython: adding panel to wx.Frame disables/conflicts with wx.Frame's OnPaint?!

  - by sdaau

  Hi all, I just encountered this strange situation: I found an example, where wx.Frame's OnPaint is overridden, and a circle is drawn. Funnily, as soon as I add even a single panel to the frame, the circle is not drawn anymore - in fact, OnPaint is not called at all anymore ! Can anyone explain me if this is the expected behavior, and how to correctly handle a wx.Frame's OnPaint, if the wx.Frame has child panels ? Small code example is below.. Thanks in advance for any answers, Cheers! The code: #!/usr/bin/env python # http://www.linuxquestions.org/questions/programming-9/wxwidgets-wxpython-drawing-problems-with-onpaint-event-703946/ import wx class MainWindow(wx.Frame): def __init__(self, parent, title, size=wx.DefaultSize): wx.Frame.__init__(self, parent, wx.ID_ANY, title, wx.DefaultPosition, size) self.circles = list() self.displaceX = 30 self.displaceY = 30 circlePos = (self.displaceX, self.displaceY) self.circles.append(circlePos) ## uncommenting either only first, or both of ## the commands below, causes OnPaint *not* to be called anymore! #~ self.panel = wx.Panel(self, wx.ID_ANY) #~ self.mpanelA = wx.Panel(self.panel, -1, size=(200,50)) self.Bind(wx.EVT_PAINT, self.OnPaint) def OnPaint(self, e): print "OnPaint called" dc = wx.PaintDC(self) dc.SetPen(wx.Pen(wx.BLUE)) dc.SetBrush(wx.Brush(wx.BLUE)) # Go through the list of circles to draw all of them for circle in self.circles: dc.DrawCircle(circle[0], circle[1], 10) def main(): app = wx.App() win = MainWindow(None, "Draw delayed circles", size=(620,460)) win.Show() app.MainLoop() if __name__ == "__main__": main()

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• Android - Temporal & Ancestral Navigation with ViewPager & Fragments

  - by rascuache

  I'm trying to work out the best way to implement the 'ancestral' and 'temporal' navigation (utilising the up button and back buttons), for a music player I'm working on. Currently, the user is presented with a viewpager, and can page between three main fragments (ArtistMain, AlbumMain and SongMain). Upon choosing an item inside that view, a fragment transaction occurs, and the viewpager goes out of view, replaced by a new fragment (AlbumSub, Songsub or player, depending on where the user came from). The user can then navigate deeper, until a song is chosen, and then they are taken to the 'player' screen. I guess the question is: How do I implement all of this conditional navigation? I'm fairly new to android and programming in general, and I just can't seem to come up with an efficient way to achieve this. At the moment, as each fragment is brought into view, the app is checking to see where the user just came from, and then determines where the user should be taken if back or home is called. This means I have a booleans like "fromArtistMain", "fromAlbumSub", and I'm checking for things like "fromSongSub && fromPlayer".. it's all turning into a bit of a mess. I've drawn a diagram (in paint, sorry!!), to depict the navigation I'm trying to achieve. The yellow represents the 'up' button press, the red is the 'back' button press, and blue is just normal navigation. The green arrows are meant to represent the view paging: Any advice is welcome. It might take something really simple that I've just overlooked. Thanks for your time.

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• Cobol web development/hosting resources

  - by felixm

  Hello, I'm employed at a fairly big company here in Germany and got the job to create the main website for it which will feature: Static contents; Information and Presentations An employee area (around 6000 employees) featuring various things from calenders, job descriptions, some sort of groups Too many other dynamic things I can't list here I have decided to use COBOL for the job, it may be very underrated but it is a very powerful language, especially for business apps and, as my co-workers say, web (2.0) development too. I also need to use COBOL because all the backend and transactions system of the company is programmed in it (some small parts were programmed in LISP too, idk exactly why). I also have received an API that makes it possible to use COBOL with MySQL easily. This is a big project and it will probably take more than 2 months programming it. What do I have to expect when building a huge web app in COBOL? Are there web frameworks for COBOL available? Some sort of MVC? Are there any good resources for practical web-development with COBOL? Thanks in advance

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• How to transform vertical table into horizontal table?

  - by avivo

  Hello, I have one table Person: Id Name 1 Person1 2 Person2 3 Person3 And I have its child table Profile: Id PersonId FieldName Value 1 1 Firstname Alex 2 1 Lastname Balmer 3 1 Email [email protected] 4 1 Phone +1 2 30004000 And I want to get data from these two tables in one row like this: Id Name Firstname Lastname Email Phone 1 Person1 Alex Balmer [email protected] +1 2 30004000 What is the most optimized query to get these vertical (key, value) values in one row like this? Now I have a problem that I done four joins of child table to parent table because I need to get these four fields. Some optimization is for sure possible. I would like to be able to modify this query in easy way when I add new field (key,value). What is the best way to do this? To create some StoreProcedure? I would like to have strongly types in my DB layer (C#) and using LINQ (when programming) so it means when I add some new Key, Value pair in Profile table I would like to do minimal modifications in DB and C# if possible. Actually I am trying to get some best practices in this case.

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• How to access hidden template in unnamed namespace?

  - by Johannes Schaub - litb

  Here is a tricky situation, and i wonder what ways there are to solve it namespace { template <class T> struct Template { /* ... */ }; } typedef Template<int> Template; Sadly, the Template typedef interferes with the Template template in the unnamed namespace. When you try to do Template<float> in the global scope, the compiler raises an ambiguity error between the template name and the typedef name. You don't have control over either the template name or the typedef-name. Now I want to know whether it is possible to: Create an object of the typedefed type Template (i.e Template<int>) in the global namespace. Create an object of the type Template<float> in the global namespace. You are not allowed to add anything to the unnamed namespace. Everything should be done in the global namespace. This is out of curiosity because i was wondering what tricks there are for solving such an ambiguity. It's not a practical problem i hit during daily programming.

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• How can i get rid of 0xFEEFEE in VC

  - by egebilmuh

  Hi guys I m programming C for an assingment in VC++ 2008. I simulate adjList for graph implementation. i can readly add edge between two vertex and print the graph. and i want to remove edge between two vertex and print the graph again. whatever i do,i cant print the graph after deleting the edge. i get 0xfeefee :( what is this? and how can i resolve this program. my delete function and print the graph function are illustrated below. void deleteEdge(Graph G, Vertex V, Vertex W) { Edge list,prev,temp; list=V->list; prev=NULL; // while(list!=NULL && list->to->value!=W->value){ prev=list; list=list->next; } // have found the element. if(list!=NULL){ temp=list; // if first element of list is deleted. if(prev==NULL) list=list->next; else prev->next=list->next; // reallocate. free(temp); } } void GRAPHprint(Graph G) { Vertex tmp; Edge list; for(tmp = G->head;tmp!=NULL;tmp=tmp->next) { fprintf(stdout,"V:%d\t",tmp->value); list=tmp->list; while(list!=NULL) { fprintf(stdout,"%d\t",list->to->value); list=list->next; } fprintf(stdout, "\n"); } system("pause"); }

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• Select all points in a matrix within 30m of another point

  - by pinnacler

  So if you look at my other posts, it's no surprise I'm building a robot that can collect data in a forest, and stick it on a map. We have algorithms that can detect tree centers and trunk diameters and can stick them on a cartesian XY plane. We're planning to use certain 'key' trees as natural landmarks for localizing the robot, using triangulation and trilateration among other methods, but programming this and keeping data straight and efficient is getting difficult using just Matlab. Is there a technique for sub-setting an array or matrix of points? Say I have 1000 trees stored over 1km (1000m), is there a way to say, select only points within 30m radius of my current location and work only with those? I would just use a GIS, but I'm doing this in Matlab and I'm unaware of any GIS plugins for Matlab. I forgot to mention, this code is going online, meaning it's going on a robot for real-time execution. I don't know if, as the map grows to several miles, using a different data structure will help or if calculating every distance to a random point is what a spatial database is going to do anyway. I'm thinking of mirroring two arrays, one sorted by X and the other by Y. Then bubble sorting to determine the 30m range in that. I do the same for both arrays, X and Y, and then have a third cross link table that will select the individual values. But I don't know, what that's called, how to program that and I'm sure someone already has so I don't want to reinvent the wheel. Cartesian Plane GIS

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• OOP - Handling Automated Instances of a Class - PHP

  - by dscher

  This is a topic that, as a beginner to PHP and programming, sort of perplexes me. I'm building a stockmarket website and want users to add their own stocks. I can clearly see the benefit of having each stock be a class instance with all the methods of a class. What I am stumped on is the best way to give that instance a name when I instantiate it. If I have: class Stock() { ....doing stuff..... } what is the best way to give my instances of it a name. Obviously I can write: $newStock = new Stock(); $newStock.getPrice(); or whatever, but if a user adds a stock via the app, where can the name of that instance come from? I guess that there is little harm in always creating a new child with $newStock = new Stock() and then storing that to the DB which leads me to my next question! What would be the best way to retrieve 20 user stocks(for example) into instances of class Stock()? Do I need to instantiate 20 new instances of class Stock() every time the user logs in or is there something I'm missing? I hope someone answers this and more important hope a bunch of people answer this and it somehow helps someone else who is having a hard time wrapping their head around what probably leads to a really elegant solution. Thanks guys!

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• is there a Universal Model for languages?

  - by Smandoli

  Many programming languages share generic and even fairly universal features. For example, if you compared Java, VB6, .NET, PHP, Python, then you would find common functions such as control structures, numeric and string manipulation, etc. What has been done to define these features at a meta-language (or language-agnostic) level? UML offers a descriptive reference of software in every aspect, but the real-world focus seems to be data processes. Is UML relevant? I'm not asking "Why we don't have a single language that replaces the current plethora." We need many different tools (at least in this eon). I'm not asking that all languages fit a template -- assembly vs. compiled languages are different enough to make that unfeasible (and some folks call HTML a language, though I wouldn't). Any attempt would start with a properly narrow scope. In line with this, I wouldn't expect the model to cover even a small selection with full validity. I would expect however that such a model could be used to transpose from one language to another (with limited goals -- think jist translation).

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• Drag and Drop in Silverlight with F# and Asynchronous Workflows

  - by knotig

  Hello everyone! I'm trying to implement drag and drop in Silverlight using F# and asynchronous workflows. I'm simply trying to drag around a rectangle on the canvas, using two loops for the the two states (waiting and dragging), an idea I got from Tomas Petricek's book "Real-world Functional Programming", but I ran into a problem: Unlike WPF or WinForms, Silverlight's MouseEventArgs do not carry information about the button state, so I can't return from the drag-loop by checking if the left mouse button is no longer pressed. I only managed to solve this by introducing a mutable flag. Would anyone have a solution for this, that does not involve mutable state? Here's the relevant code part (please excuse the sloppy dragging code, which snaps the rectangle to the mouse pointer): type MainPage() as this = inherit UserControl() do Application.LoadComponent(this, new System.Uri("/SilverlightApplication1;component/Page.xaml", System.UriKind.Relative)) let layoutRoot : Canvas = downcast this.FindName("LayoutRoot") let rectangle1 : Rectangle = downcast this.FindName("Rectangle1") let mutable isDragged = false do rectangle1.MouseLeftButtonUp.Add(fun _ -> isDragged <- false) let rec drag() = async { let! args = layoutRoot.MouseMove |> Async.AwaitEvent if (isDragged) then Canvas.SetLeft(rectangle1, args.GetPosition(layoutRoot).X) Canvas.SetTop(rectangle1, args.GetPosition(layoutRoot).Y) return! drag() else return() } let wait() = async { while true do let! args = Async.AwaitEvent rectangle1.MouseLeftButtonDown isDragged <- true do! drag() } Async.StartImmediate(wait()) () Thank you very much for your time!

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• Objective-C and NSURL: where am I supposed to declare receivedData?

  - by jthomas

  I have a two classes, a controller called "AppController" and a class called "URLDelegate" that encapsulates the sample NSURL code from Apple's URL Loading System Programming Guide. The guide repeatedly mentions declaring the receivedData instance variable "elsewhere." I assume this means outside of the URLDelagate class, because if I declare it in the URLDelegate class, my controller class can't "see" the data that has been downloaded. I know that data is received, because in my connectionDidFinishLoading function, I have NSLog display the results: NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]); receivedText=[[NSString alloc] initWithData:receivedData encoding: NSASCIIStringEncoding]; NSLog(@"receivedText=%@",receivedText); So I'm a bit stumped with the following questions: Where should I declare receivedData? My controller class? A third class? Can I just declare it like any normal NSMutableData variable? How do I give my URLDelegate class "access" to this variable? E.g., if I declare receivedData in my AppController class, wouldn't I have to instantiate AppController within URLDelegate? But how would this possible if it's the AppController class which is instantiating the URLDelegate class in the first place? Especially with regard to the last question, I feel like I must be overlooking something blindingly obvious and fundamental. If anyone could point me in the right direction, I would really appreciate it. Thank you!

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• Are women worse developers than men? [closed]

  - by Ekaterina

  Hi people, I am a software engineer and a woman. I constantly keep hearing all these jokes around me, about women in programming. They (they - stands for male colleagues) keep pointing out the differences in thinking between men and women. The truth is that when I started working as a developer, my colleagues gave a hard time only because I am a woman. They automatically assumed that I want to do only html and styling, and didn't even me giving me the chance to do something different. I am a .NET programmer and I really disliked (and still dislike) front-end developing. I do agree men and women think differently, but I don't agree that necessarily is a bad thing. Different approach of problems/goals brings more ideas and diversity. I really believe that there are good developer and bad developers despite the male/female factor. I am curious to hear overall opinion though. Would you not hire a woman developer only because is a woman? Cheers!

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• Simulated Annealing and Yahtzee!

  - by Jasie

  I've picked up Programming Challenges and found a Yahtzee! problem which I will simplify: There are 13 scoring categories There are 13 rolls by a player (comprising a play) Each roll must fit in a distinct category The goal is to find the maximum score for a play (the optimal placement of rolls in categories); score(play) returns the score for a play Brute-forcing to find the maximum play score requires 13! (= 6,227,020,800) score() calls. I choose simulated annealing to find something close to the highest score, faster. Though not deterministic, it's good enough. I have a list of 13 rolls of 5 die, like: ((1,2,3,4,5) #1 (1,2,6,3,4),#2 ... (1,4,3,2,2) #13 ) And a play (1,5,6,7,2,3,4,8,9,10,13,12,11) passed into score() returns a score for that play's permutation. How do I choose a good "neighboring state"? For random-restart, I can simply choose a random permutation of nos. 1-13, put them in a vector, and score them. In the traveling salesman problem, here's an example of a good neighboring state: "The neighbours of some particular permutation are the permutations that are produced for example by interchanging a pair of adjacent cities." I have a bad feeling about simply swapping two random vector positions, like so: (1,5,6,7, 2 , 3,4,8,9,10, 13, 12,11) # switch 2 and 13 (1,5,6,7, 13, 3,4,8,9,10, 2 , 12,11) # now score this one But I have no evidence and don't know how to select a good neighboring state. Anyone have any ideas on how to pick good neighboring states?

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• Python creating a dictionary and swapping these into another file

  - by satsurae

  Hi all, I have two tab delimited .csv file. From one.csv I have created a dictionary which looks like: 'EB2430': ' "\t"idnD "\t"yjgV "\t"b4267 "\n', 'EB3128': ' "\t"yagE "\t\t"b0268 "\n', 'EB3945': ' "\t"maeB "\t"ypfF "\t"b2463 "\n', 'EB3944': ' "\t"eutS "\t"ypfE "\t"b2462 "\n', I would like to insert the value of the dictionary into the second.csv file which looks like: "EB2430" 36.81 364 222 4 72 430 101 461 1.00E-063 237 "EB3128" 26.04 169 108 6 42 206 17 172 6.00E-006 45.8 "EB3945" 20.6 233 162 6 106 333 33 247 6.00E-005 42.4 "EB3944" 19.07 367 284 6 1 355 1 366 2.00E-023 103 With a resultant output tab delimited: 'EB2430' idnD yjgV b4267 36.81 364 222 4 72 430 101 461 1.00E-063 237 'EB3128' yagE b0268 26.04 169 108 6 42 206 17 172 6.00E-006 45.8 'EB3945' maeB ypfF b2463 20.6 233 162 6 106 333 33 247 6.00E-005 42.4 'EB3944' eutS ypfE b2462 19.07 367 284 6 1 355 1 366 2.00E-023 103 Here is my code for creating the dictionary: f = open ("one.csv", "r") g = open ("second.csv", "r") eb = [] desc = [] di = {} for line in f: for row in f: eb.append(row[1:7]) desc.append(row[7:]) di = dict(zip(eb,desc)) Sorry for it being so long-winded!! I've not been programming for long. Cheers! Sat

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