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  • Determining where in the code an error came from - iPhone

    - by Robert Eisinger
    I'm used to Java programming where an error is thrown and it tells you at what line the error was thrown from which file. But with Objective-C in XCode, I can't ever tell where the error comes from. How can I figure out where the error came from? Here is an example of a crash error: 2011-01-04 10:36:31.645 TestGA[69958:207] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSMutableArray objectAtIndex:]: index 0 beyond bounds for empty array' *** Call stack at first throw: ( 0 CoreFoundation 0x01121be9 __exceptionPreprocess + 185 1 libobjc.A.dylib 0x012765c2 objc_exception_throw + 47 2 CoreFoundation 0x011176e5 -[__NSArrayM objectAtIndex:] + 261 3 TestGA 0x000548d8 -[S7GraphView drawRect:] + 5763 4 UIKit 0x003e16eb -[UIView(CALayerDelegate) drawLayer:inContext:] + 426 5 QuartzCore 0x00ec89e9 -[CALayer drawInContext:] + 143 6 QuartzCore 0x00ec85ef _ZL16backing_callbackP9CGContextPv + 85 7 QuartzCore 0x00ec7dea CABackingStoreUpdate + 2246 8 QuartzCore 0x00ec7134 -[CALayer _display] + 1085 9 QuartzCore 0x00ec6be4 CALayerDisplayIfNeeded + 231 10 QuartzCore 0x00eb938b _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 325 11 QuartzCore 0x00eb90d0 _ZN2CA11Transaction6commitEv + 292 12 QuartzCore 0x00ee97d5 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 99 13 CoreFoundation 0x01102fbb __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 27 14 CoreFoundation 0x010980e7 __CFRunLoopDoObservers + 295 15 CoreFoundation 0x01060bd7 __CFRunLoopRun + 1575 16 CoreFoundation 0x01060240 CFRunLoopRunSpecific + 208 17 CoreFoundation 0x01060161 CFRunLoopRunInMode + 97 18 GraphicsServices 0x01932268 GSEventRunModal + 217 19 GraphicsServices 0x0193232d GSEventRun + 115 20 UIKit 0x003b842e UIApplicationMain + 1160 21 TestGA 0x00001cd8 main + 102 22 TestGA 0x00001c69 start + 53 23 ??? 0x00000001 0x0 + 1 So from looking at this, where is the error coming from and from which class is it coming from?

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  • Simulate stochastic bipartite network based on trait values of species - in R

    - by Scott Chamberlain
    I would like to create bipartite networks in R. For example, if you have a data.frame of two types of species (that can only interact across species, not within species), and each species has a trait value (e.g., size of mouth in the predator allows who gets to eat which prey species), how do we simulate a network based on the traits of the species (that is, two species can only interact if their traits overlap in values for instance)? UPDATE: Here is a minimal example of what I am trying to do. 1) create phylogenetic tree; 2) simulate traits on the phylogeny; 3) create networks based on species trait values. # packages install.packages(c("ape","phytools")) library(ape); library(phytools) # Make phylogenetic trees tree_predator <- rcoal(10) tree_prey <- rcoal(10) # Simulate traits on each tree trait_predator <- fastBM(tree_predator) trait_prey <- fastBM(tree_prey) # Create network of predator and prey ## This is the part I can't do yet. I want to create bipartite networks, where ## predator and prey interact based on certain crriteria. For example, predator ## species A and prey species B only interact if their body size ratio is ## greater than X.

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  • Remove duplication's from my DropDownList

    - by user2976270
    In my controller i am returning list of my object with specific property: public ActionResult Index() { List<MyObject> list = db.MyObjects.Where(x => x.family == "Web").ToList(); ViewBag.Files = new SelectList(list, "Id", "protocol"); return View(); } This is my object: public class MyObject { public int id { get; set; } public string fileName { get; set; } public string browser { get; set; } public string protocol { get; set; } public string family { get; set; } } Index.cshtml: @Html.DropDownList("File", new SelectList(ViewBag.Files, "Id", "protocol_site"), "Select webmail site", new { style = "vertical-align:middle;" }) And i try to made 2 changes with no succeed: Remove all the duplication protocol from my DropDownListfor exapmle if i have 10 objects : 9 is doc protocol and 1 pdf i wand to see in my DropDownList only 2 items: DOC and PDF and not all the 10 items. Sort this DropDownList in alphabet order

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  • Keeping track of dependency revisions

    - by Samaursa
    I have a project with several dependencies that are in various repositories. Each time I commit changes to my project, I make sure I write the revision numbers of all the dependent repositories so that in the event I ever have to come back to this revision (let's call it 5), I can immediately know which revisions of the dependent repositories revision 5 is guaranteed to work with, update the dependencies to the specified revisions, compile and run the project. So for example if I have: Dep1 @ Revisions 10 Dep2 @ Revisions 20 Dep3 @ Revisions 10 Proj @ Revisions 35 And let's say that when Proj was on revision 17, the Dep1 revision was 5, Dep2 revision was 13 and Dep3 revision was 3. So in my SVN logs, I recorded something like this: !! Works with Dep1 Rev 5, Dep2 Rev 13, Dep3 Rev 3 To me this seems primitive and makes me believe that there is a better way to do it. Now in one of my other questions, Ivy Dependency Manager has been recommended. I have not looked at it in detail yet (seems complicated and yet another thing I must learn). To me it seems like the log of SVN (and Mercurial etc.) could have been split into Log and Dependencies (if any) where the latter could be switched off if there were no dependencies (unless of course I am unaware of an easier/better solution). This would allow for a cleaner log that maybe even warned at each new commit to check the previously defined dependencies again and make sure they have not changed. So, I was wondering how everyone manages this situations and if you have any tips, techniques, programs, suggestions that you can offer. Thank you.

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  • Writing a recursive sorting algorithm of an array of integers

    - by 12345
    I am trying to write a recursive sorting algorithm for an array of integers. The following codes prints to the console: 3, 5, 2, 1, 1, 2, 6, 7, 8, 10, 20 The output should be sorted but somehow "it doesn't work". public static void main(String[] args) { int[] unsortedList = {20, 3, 1, 2, 1, 2, 6, 8, 10, 5, 7}; duplexSelectionSort(unsortedList, 0, unsortedList.length-1); for (int i = 0; i < unsortedList.length; i++) { System.out.println(unsortedList[i]); } } public static void duplexSelectionSort( int[] unsortedNumbers, int startIndex, int stopIndex) { int minimumIndex = 0; int maximumIndex = 0; if (startIndex < stopIndex) { int index = 0; while (index <= stopIndex) { if (unsortedNumbers[index] < unsortedNumbers[minimumIndex]) { minimumIndex = index; } if (unsortedNumbers[index] > unsortedNumbers[maximumIndex]) { maximumIndex = index; } index++; } swapEdges(unsortedNumbers, startIndex, stopIndex, minimumIndex, maximumIndex); duplexSelectionSort(unsortedNumbers, startIndex + 1, stopIndex - 1); } } public static void swapEdges( int[] listOfIntegers, int startIndex, int stopIndex, int minimumIndex, int maximumIndex) { if ((minimumIndex == stopIndex) && (maximumIndex == startIndex)) { swap(listOfIntegers, startIndex, stopIndex); } else { if (maximumIndex == startIndex) { swap(listOfIntegers, maximumIndex, stopIndex); swap(listOfIntegers, minimumIndex, startIndex); } else { swap(listOfIntegers, minimumIndex, startIndex); swap(listOfIntegers, maximumIndex, stopIndex); } } } public static void swap(int[] listOfIntegers, int index1, int index2) { int savedElementAtIndex1 = listOfIntegers[index1]; listOfIntegers[index1] = listOfIntegers[index2]; listOfIntegers[index2] = savedElementAtIndex1; }

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  • switch statemt functioning improperly and giving error when i put break;

    - by nav
    The following is the code i used in a program - over here the month variable is an integer switch(month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31; break; case 2: return 28; break; case 4: case 6: case 9: case 11: return 30; break; default: System.out.println("Invalid month."); return 0; } surprisingly, when i use the above switch construct.. it gives an error saying.. code unreachable for statements after each break statement Then i removed all the break statements, and the new code looks like this --- switch(month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31; case 2: return 28; case 4: case 6: case 9: case 11: return 30; default: System.out.println("Invalid month."); return 0; } Now.. after removing the break statements .. the code worked perfectly well.. My question is... in the switch construct.. it is mandatory to use break.. or else the control flow continued.. and all the conditions are tested and executed!! right??? So why in the world is the previous ** syntactically Right** version giving an error.. and the modified syntactically incorrect version running perfectly well.. Any explanation.. anyone!!

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  • Strange compilation error on reference passing argument to function

    - by Grewdrewgoo Goobergabbsoen
    Here's the code: #include <iostream> using namespace std; void mysize(int &size, int size2); int main() { int *p; int val; p = &val; cout << p; mysize(&val, 20); // Error is pointed here! } void mysize(int &size, int size2) { cout << sizeof(size); size2 = size2 + 6000; cout << size2; } Here's the error output from GCC: In function 'int main()': Line 10: error: invalid initialization of non-const reference of type 'int&' from a temporary of type 'int*' compilation terminated due to -Wfatal-errors. What does that imply? I do not understand the error message ... invalid initialization of a non-constant? I declared the prototype function above with two parameters to take, one a reference of an integer and one just an integer value itself. I passed the reference of the int (see line 10), yet this error keeps being thrown at me. What is the issue?

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  • Time taken for memcpy decreases after certain point

    - by tss
    I ve a code which increases the size of the memory(identified by a pointer) exponentially. Instead of realloc, I use malloc followed by memcpy.. Something like this.. int size=5,newsize; int *c = malloc(size*sizeof(int)); int *temp; while(1) { newsize=2*size; //begin time temp=malloc(newsize*sizeof(int)); memcpy(temp,c,size*sizeof(int)); //end time //print time in mili seconds c=temp; size=newsize; } Thus the number of bytes getting copied is increasing exponentially. The time required for this task also increases almost linearly with the increase in size. However after certain point, the time taken abruptly reduces to a very small value and then remains constant. I recorded time for similar code, copyin data(Of my own type) 5 -> 10 - 2 ms 10 -> 20 - 2 ms . . 2560 -> 5120 - 5 ms . . 20480 -> 40960 - 30 ms 40960 -> 91920 - 58 ms 367680 -> 735360 - 2 ms 735360 -> 1470720 - 2 ms 1470720 -> 2941440 - 2 ms What is the reason for this drop in time ? Does a more optimal memcpy method get called when the size is large ?

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  • Using deprecated binders and C++0x lambdas

    - by Sumant
    C++0x has deprecated the use of old binders such as bind1st and bind2nd in favor of generic std::bind. C++0x lambdas bind nicely with std::bind but they don't bind with classic bind1st and bind2nd because by default lambdas don't have nested typedefs such as argument_type, first_argument_type, second_argument_type, and result_type. So I thought std::function can serve as a standard way to bind lambdas to the old binders because it exposes the necessary typedefs. However, using std::function is hard to use in this context because it forces you to spell out the function-type while instantiating it. auto bound = std::bind1st(std::function<int (int, int)>([](int i, int j){ return i < j; }), 10); // hard to use auto bound = std::bind1st(std::make_function([](int i, int j){ return i < j; }), 10); // nice to have but does not compile. I could not find a convenient object generator for std::function. Something like std::make_fuction would be nice to have. Does such a thing exist? If not, is there any other better way of binding lamdas to the classic binders?

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  • Zimbra Problems

    - by Imax Satria
    I have a problem with my Zimbra Server, yahoo mail can't reply to my Zimbra Server, this the failure notice from yahoo : Sorry, we were unable to deliver your message to the following address. : No MX or A records for imaxsatria.25u.com --- Below this line is a copy of the message. Received: from [106.10.166.123] by nm17.bullet.mail.sg3.yahoo.com with NNFMP; 30 Aug 2012 00:06:07 -0000 Received: from [106.10.151.252] by tm12.bullet.mail.sg3.yahoo.com with NNFMP; 30 Aug 2012 00:06:07 -0000 Received: from [127.0.0.1] by omp1001.mail.sg3.yahoo.com with NNFMP; 30 Aug 2012 00:06:07 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: [email protected] Received: (qmail 46619 invoked by uid 60001); 30 Aug 2012 00:06:07 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1346285167; bh=JOd9hQyuDhBSxyuVvYQwIVOo6Dp7C1wsnvprDYxGUn8=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; ................... Can you help me?

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  • Efficiently select top row for each category in the set

    - by VladV
    I need to select a top row for each category from a known set (somewhat similar to this question). The problem is, how to make this query efficient on the large number of rows. For example, let's create a table that stores temperature recording in several places. CREATE TABLE #t ( placeId int, ts datetime, temp int, PRIMARY KEY (ts, placeId) ) -- insert some sample data SET NOCOUNT ON DECLARE @n int, @ts datetime SELECT @n = 1000, @ts = '2000-01-01' WHILE (@n>0) BEGIN INSERT INTO #t VALUES (@n % 10, @ts, @n % 37) IF (@n % 10 = 0) SET @ts = DATEADD(hour, 1, @ts) SET @n = @n - 1 END Now I need to get the latest recording for each of the places 1, 2, 3. This way is efficient, but doesn't scale well (and looks dirty). SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 1 ORDER BY ts DESC ) t1 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 2 ORDER BY ts DESC ) t2 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 3 ORDER BY ts DESC ) t3 The following looks better but works much less efficiently (30% vs 70% according to the optimizer). SELECT placeId, ts, temp FROM ( SELECT placeId, ts, temp, ROW_NUMBER() OVER (PARTITION BY placeId ORDER BY ts DESC) rownum FROM #t WHERE placeId IN (1, 2, 3) ) t WHERE rownum = 1 The problem is, during the latter query execution plan a clustered index scan is performed on #t and 300 rows are retrieved, sorted, numbered, and then filtered, leaving only 3 rows. For the former query three times one row is fetched. Is there a way to perform the query efficiently without lots of unions?

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  • Calculate distances and sort them

    - by Emir
    Hi guys, I wrote a function that can calculate the distance between two addresses using the Google Maps API. The addresses are obtained from the database. What I want to do is calculate the distance using the function I wrote and sort the places according to the distance. Just like "Locate Store Near You" feature in online stores. I'm going to specify what I want to do with an example: So, lets say we have 10 addresses in database. And we have a variable $currentlocation. And I have a function called calcdist(), so that I can calculate the distances between 10 addresses and $currentlocation, and sort them. Here is how I do it: $query = mysql_query("SELECT name, address FROM table"); while ($write = mysql_fetch_array($query)) { $distance = array(calcdist($currentlocation, $write["address"])); sort($distance); for ($i=0; $i<1; $i++) { echo "<tr><td><strong>".$distance[$i]." kms</strong></td><td>".$write['name']."</td></tr>"; } } But this doesn't work very well. It doesn't sort the numbers. Another challenge: How can I do this in an efficient way? Imagine there are infinite numbers of addresses; how can I sort these addresses and page them?

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  • Query returning related assets

    - by GMo
    I have 2 tables, one is an assets table which holds digital assets (e.g. article, images etc), the 2nd table is an asset_links table which maps 1-1 relationships between assets contained within the assets table. Here are the table definitions: Asset +---------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | source | varchar(255) | YES | | NULL | | | title | varchar(255) | YES | | NULL | | | date_created | datetime | YES | | NULL | | | date_embargo | datetime | YES | | NULL | | | date_expires | datetime | YES | | NULL | | | date_updated | datetime | YES | | NULL | | | keywords | varchar(255) | YES | | NULL | | | status | int(11) | YES | | NULL | | | priority | int(11) | YES | | NULL | | | fk_site | int(11) | YES | MUL | NULL | | | resource_type | varchar(255) | YES | | NULL | | | resource_id | int(11) | YES | | NULL | | | fk_user | int(11) | YES | MUL | NULL | | +---------------+--------------+------+-----+---------+----------------+ Asset_links +-----------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------+---------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | asset_id1 | int(11) | YES | | NULL | | | asset_id2 | int(11) | YES | | NULL | | +-----------+---------+------+-----+---------+----------------+ In the asset_links table there are the following rows: 1 - 3, 1 - 4, 2 - 10, 2 - 56 I am looking to write one query which will return all assets which satisfy any asset search criteria and within the same query return all of the linked asset data for linked assets for that asset. e.g. The query returning assets 1 and 2 would return : Asset 1 attributes - Asset 3 attributes - Asset 4 attributes Asset 2 attributes - Asset 10 attributes - Asset 56 attributes What is the best way to write the query?

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  • Move and rename file in android

    - by Andre Fróes
    I am trying to copy a file to another folder in the android, but so far, i got no success. I manage to do so with a selected image and when taking a photo, but not with files. I've read and tried several solutions passed by the community (searched over the forum and the internet), but none of it was able to solve my problem when copying. First things first. I added the permissions to my manifest: <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> after that, before copying a file, i print its filepath and the directory file path: 06-10 11:11:11.700: I/System.out(1442): /mimetype/storage/sdcard/Misc/Javascript erros for Submit and Plan buttons in IE.doc 06-10 11:11:11.710: I/System.out(1442): /storage/sdcard/mywfm/checklist-files both exists: to copy the file to the expected folder I used the FileUtils: try { FileUtils.copyFile(selectedFile, dir); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } The problem is: I get no exception and the file isn't there. I tried this solution either: How to move/rename file from internal app storage to external storage on Android? same thing, no exception, but no file either.

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  • Getting the value of an input inside a td for each row with jQuery

    - by Anne
    I am still having so many problems with this: function padTitles() { $('tr').each(function () { var tds = $(this).find('input'), text = tds.filter('[id^="TempRowKey_"]').val(), tdToPad = tds.filter('[id^="title_"]'), pad; if (/0\.0$/.test(text)) pad = 10; else if (/\.0$/.test(text)) pad = 35; else pad = 60; tdToPad.css('paddingLeft', pad); }); } Note: here is what I was using before. This worked when the value was not inside an input: var tds = $(this).find('td'), text = tds.filter('[id^="refKey_"]').text(), It is supposed to get the Value of the Inputs with id's that start with TempRowKey_ and then use these for padding. But the code does nothing. Here is my HTML: <tr id="row_1"> <td id="tempRowKey_1" > <input type="text" size="10" value="1.0.0" class="updatable" id="TempRowKey_1"> </td> <td id="title_1"> <input id="Title_1" class="updatable" type="text" value="zxxx" size="100" name="item.Title"> </td>. <td ... </tr> Is there some way I can test this. I can't get access to anything inside the jQuery block?

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  • Cannot get MEDIA_URL from Django widget's template

    - by Eric
    Hi folks, I am a new Djangoer, and figuring out how to build custom widget, my problem is cannot get the MEDIA_URL in my widget's template, while the form use MySelectWidget able to get the MEDIA_URL itself. # #plus_sign.html # <a href="" class="" id="id_{{ field }}"> <img src="{{ MEDIA_URL }}images/plus_sign.gif" width="10" height="10" alt="Add"/> </a> *^ cannot load the {{ MEDIA_URL}} to this widget's template, and therefore I can't load the .gif image properly. :(* # #custom_widgets.py # from django import forms class MySelectMultiple(forms.SelectMultiple): def render(self, name, *args, **kwargs): html = super(MySelectMultiple, self).render(name, *args, **kwargs) plus = render_to_string("plus_sign.html", {'field': name}) return html+plus # #forms.py # from django import forms from myapp.custom_widgets.py import MySelectMultiple class MyForm(forms.ModelForm): contacts = forms.ModelMultipleChoiceField(Contact.objects, required=False, widget=MySelectMultiple) # #views.py # def AddContacts(request): if request.method == 'POST': form = MyForm(request.POST) if form.is_valid(): cd = form.cleaned_data new = form.save() return HttpResponseRedirect('/addedContact/') else: form = MyForm() return render_to_response('shop/my_form.html', {'form': form}, context_instance=RequestContext(request)) # #my_form.html # {% extends "base.html" %} {% block content %} {{ form.contacts }} {% endblock %} Please let me know how can I load the widget's image properly. Thank you so much for all responses.

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  • Waiting for data via select not working

    - by BSchlinker
    I'm currently working on a project which involves multiple clients connected to a server and waiting for data. I'm using select and monitoring the connection for incoming data. However, the client just continues to print nothing, acting as if select has discovered incoming data. Perhaps I'm attacking this wrong? For the first piece of data the server does send, it is displayed correctly. However, the server then disconnects and the client continues to spew blank lines. FD_ZERO(&readnet); FD_SET(sockfd, &readnet); while(1){ rv = select(socketdescrip, &readnet, NULL, NULL, &timeout); if (rv == -1) { perror("select"); // error occurred in select() } else if (rv == 0) { printf("Connection timeout! No data after 10 seconds.\n"); } else { // one or both of the descriptors have data if (FD_ISSET(sockfd, &readnet)) { numbytes = recv(sockfd, buf, sizeof buf, 0); printf("Data Received\n"); buf[numbytes] = '\0'; printf("client: received '%s'\n",buf); sleep(10); } } }

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  • How do I redirect standard output to a file in Perl? [closed]

    - by rockyurock
    I want to send standard output to the file "my_output.txt" but failed. Here's the output: inside value loop ------------------------------------------------------------ Server listening on UDP port 5001 Receiving 1470 byte datagrams UDP buffer size: 108 KByte (default) ------------------------------------------------------------ [ 3] local 192.168.16.2 port 5001 connected with 192.168.16.1 port 3189 [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 3] 0.0- 5.0 sec 2.14 MBytes 3.61 Mbits/sec 0.369 ms 0/ 1528 (0%) inside value loop3 clue1 clue2 inside value loop4 one iperf completed *************************************** When I enable the local *STDOUT; in below code then I could see the above output on command prompt display (ofcourse server is sending some data): my $file = 'my_output.txt'; use Win32::Process; print"inside value loop\n"; # redirect stdout to a file #local *STDOUT; open STDOUT, '>', $file or die "can't redirect STDOUT to <$file> $!"; Win32::Process::Create(my $ProcessObj, "D:\\IOT_AUTOMATION_UTILITY\\_SATURDAY_09-04-10\\adb_cmd.bat", "adb shell /data/app/iperf -u -s -p 5001", 0, NORMAL_PRIORITY_CLASS, ".") || die ErrorReport(); #$alarm_time = $IPERF_RUN_TIME+10; #20sec #$ProcessObj->Wait(40); #print"inside value loop2\n"; #sleep $alarm_time; sleep 40; $ProcessObj->Kill(0); sub ErrorReport{ print Win32::FormatMessage( Win32::GetLastError() ); }

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  • Understanding C++ pointers (when they point to a pointer)

    - by Stephano
    I think I understand references and pointers pretty well. Here is what I (think I) know: int i = 5; //i is a primitive type, the value is 5, i do not know the address. int *ptr; //a pointer to an int. i have no way if knowing the value yet. ptr = &i; //now i have an address for the value of i (called ptr) *ptr = 10; //go get the value stored at ptr and change it to 10 Please feel free to comment or correct these statements. Now I'm trying to make the jump to arrays of pointers. Here is what I do not know: char **char_ptrs = new char *[50]; Node **node_ptrs = new Node *[50]; My understanding is that I have 2 arrays of pointers, one set of pointers to chars and one to nodes. So if I wanted to set the values, I would do something like this: char_ptrs[0] = new char[20]; node_ptrs[0] = new Node; Now I have a pointer, in the 0 position of my array, in each respective array. Again, feel free to comment here if I'm confused. So, what does the ** operator do? Likewise, what is putting a single * next to the instantiation doing (*[50])? (what is that called exactly, instantiation?)

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  • Just 2 free months to learn or improve my skills

    - by microspino
    On the 30 of June I will leave my every day work to start as freelance developer. I'd like to set a period of 2 months apart to improve my dev skills. At work I code in C# and during my spare time I enjoyed building Ruby on Rails web applications and creating some Arduino prototypes. I'm something more than junior but I don't feel really a senior developer because I never had a big corporate project built and designed by me with help of other juniors (although I don't think this is really a good definiton of a "senior", It helps describing my feelings). Using a scale from 0 (ignorant) to 10 (proficient like a "samurai") the list below describes my skills that I would like to improve with just 2 months. I've already bought some nice and updated books on all the subjects hereunder: The order doesn't matter C = 1 C# & .Net = 6 Arduino & Processing = 2 Ruby = 5 Rails = 5 HTML/XHTML/CSS = 9 Javascript = 6 Objective-C/iPhone dev = 2 Python = 4 Django = 4 Desing Patterns = 3 Algorythms = 3 Git = 5 I haven't included SQL or Databases in general nor Networking because I spent 10 years working in the past with them and I feel pretty solid for now. As an aside, I've made up some interest in Redis, Node.js, HTML5 reading about them on the web. After two months, since I have to pay my bills, I could go searching for some new job. If learning and developing were really good maybe I could also invest on something I gave birth during them. Can You give me some piece of advice on which you think It's better to improve or develop a learning project on (something like a "summer of code" thing)? The all point Is to see my weaknesses and work on them.

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  • Problem with reading and writing to binary file in C++

    - by Reem
    I need to make a file that contains "name" which is a string -array of char- and "data" which is array of bytes -array of char in C++- but the first problem I faced is how to separate the "name" from the "data"? newline character could work in this case (assuming that I don't have "\n" in the name) but I could have special characters in the "data" part so there's no way to know when it ends so I'm putting an int value in the file before the data which has the size of the "data"! I tried to do this with code as follow: if((fp = fopen("file.bin","wb")) == NULL) { return false; } char buffer[] = "first data\n"; fwrite( buffer ,1,sizeof(buffer),fp ); int number[1]; number[0]=10; fwrite( number ,1,1, fp ); char data[] = "1234567890"; fwrite( data , 1, number[0], fp ); fclose(fp); but I didn't know if the "int" part was right, so I tried many other codes including this one: char buffer[] = "first data\n"; fwrite( buffer ,1,sizeof(buffer),fp ); int size=10; fwrite( &size ,sizeof size,1, fp ); char data[] = "1234567890"; fwrite( data , 1, number[0], fp ); I see 4 "NULL" characters in the file when I open it instead of seeing an integer. Is that normal? The other problem I'm facing is reading that again from the file! The code I tried to read didn't work at all :( I tried it with "fread" but I'm not sure if I should use "fseek" with it or it just read the other character after it. Forgive me but I'm a beginner :(

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  • Is it true that in most Object Oriented Programming Languages, an "i" in an instance method always r

    - by Jian Lin
    In the following code: <script type="text/javascript"> var i = 10; function Circle(radius) { this.r = radius; this.i = radius; } Circle.i = 123; Circle.prototype.area = function() { alert(i); } var c = new Circle(1); var a = c.area(); </script> What is being alerted? The answer is at the end of this question. I found that the i in the alert call either refers to any local (if any), or the global variable. There is no way that it can be the instance variable or the class variable even when there is no local and no global defined. To refer to the instance variable i, we need this.i, and to the class variable i, we need Circle.i. Is this actually true for almost all Object oriented programming languages? Any exception? Are there cases that when there is no local and no global, it will look up the instance variable and then the class variable scope? (or in this case, are those called scope?) the answer is: 10 is being alerted.

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  • Update a portion UIView

    - by Brett
    Hi; I'm using -setNeedsDisplayinRect to update only a part of my UIView. However, all of my drawing done previously to calling this method is erased. Here is my code in the UIView subclass: -(void)drawRect:(CGRect)rect{ CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetRGBFillColor(context, r, g, b, 1); CGContextSetRGBStrokeColor(context, r, g, b, 1); CGRect arect = CGRectMake(x,y,1,1); CGContextFillRect(context, arect); NSLog(@"drawing"); } and in the view controller: -(void)drawView{ drawingView = [[DrawingView alloc]init]; x=10; y=10; r=0; g=0; b=0; [drawingView setNeedsDisplayInRect:CGRectMake(x, y, 1, 1)]; x=20; y=20; r=0; g=0; b=0; [drawingView setNeedsDisplayInRect:CGRectMake(x, y, 1, 1)]; } I end up with a screen where there is only one pixel at 20,20. Any help with this is so much appreciated. I am a beginner with XCode and am trying to complete a class project asap.

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  • odd url, and difficulty in following the php page flow

    - by sdfor
    I'm trying to understand code that I bought so I can modify it. In the index.php there are picture links: <a href="test10,10"><img title="" border=1 src="makethumb.php?pic=product_images/test101.jpg&amp;w=121&amp;sq=N" / ></a> I don't understand the href since it is not pointing to a page. test10 is an id of a picture. I assumed it was going back to the index.php and the code would extract the test10,10 from the url, but it's not. I know that because I put in trace code as the first line. The question is, where is the link going to? I know it that it somewhere in the process it executes a page called profile.php, but nowhere in the source code (doing a global search) is there an explicit call to profile.php. As a related question, is there a way to profile the code to see what pages it's calling without using xdebug, which for the life of me I can't get working after many hours of trying every suggestion I found here and else where. (I'm using xampp) thanks

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  • adding elements in to the doubly linked list

    - by user329820
    Hi this is my code for main class and doubly linked class and node class but when I run the program ,in the concole will show this"datastructureproject.DoublyLinkedList@19ee1ac" instead of the random numbers .please help me thanks! main class: public class Main { public static int getRandomNumber(double min, double max) { Random random = new Random(); return (int) (random.nextDouble() * (max - min) + min); } public static void main(String[] args) { int j; int i = 0; i = getRandomNumber(10, 10000); DoublyLinkedList listOne = new DoublyLinkedList(); for (j = 0; j <= i / 2; j++) { listOne.add(getRandomNumber(10, 10000)); } System.out.println(listOne); } } doubly linked list class: public class DoublyLinkedList { private Node head ; private Node tail; private long size = 0; public DoublyLinkedList() { head= new Node(0, null, null); tail = new Node(0, head, null); } public void add(int i){ head.setValue(i); Node newNode = new Node(); head.setNext(newNode); newNode.setPrev(head); newNode = head; } } and the node class is like the class that you have seen before (Node prev,Node next,int value)

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